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_______________________________________________________________ maxim integrated products 1 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxims website at www.maxim-ic.com. max3107 spi/i 2 c uart with 128-word fifos 19-5014; rev 3; 8/11 + denotes a lead(pb)-free/rohs-compliant package. * ep = exposed pad. /v denotes an automotive qualified part. t = tape and reel. functional diagram appears at end of data sheet. general description the max3107 is an advanced universal asynchronous receiver-transmitter (uart) with 128 words each of receive and transmit first-in/first-out (fifo) that can be controlled through i 2 c or high-speed spi?. the 2x and 4x rate modes allow a maximum of 24mbps data rates. a phase-locked loop (pll), prescaler, and fractional baud-rate generator allow for high-resolution baud-rate programming and minimize the dependency of baud rate on reference clock frequency. autosleep and shutdown modes help reduce power consumption during periods of inactivity. a low 640a (typ) supply current and tiny 24-pin tqfn (3.5mm x 3.5mm) package make the max3107 ideal for low-power portable devices. integrated logic-level translation on the controller and transceiver (rx/tx and rts / cts ) interfaces enable use with a wide selection of rs-232/rs-485 transceivers. automatic hardware and software flow control with selectable fifo interrupt triggering offloads low-level activity from the host controller. automatic half-duplex transceiver control with programmable setup and hold times allow the max3107 to be used in high-speed appli - cations, for example profibus-dp. the max3107 is ideal for use in portable devices, industrial applications, and automotive applications. the max3107 is available in a 24-pin ssop package and a 24-pin tqfn package. it is specified over the -40 n c to +85 n c extended ambient temperature range. applications portable devices industrial control systems fieldbus networks automotive infotainment systems medical systems point-of-sale systems hvac or building control features s 24-pin, lead-free tqfn (3.5mm x 3.5mm) and 24-pin, lead-free ssop packages s 24mbps (max) data rate s integrated pll and divider s fractional baud-rate generator s spi up to 26mhz clock rate s auto transceiver direction control s half-duplex echo suppression s auto rts/cts and xon/xoff flow control s special character detection s gpio-based character detection s 9-bit multidrop-mode data filtering s sir- and mir-compliant irda encoder/decoder s +2.35v to +3.6v supply range s logic-level translation on the controller and transceiver interfaces (down to 1.7v) s four flexible gpios s line noise indication s shutdown and autosleep modes s low 640a (typ) supply current at 1mbaud and 20mhz clock s low 20a (typ) shutdown power ordering information spi is a trademark of motorola, inc. evaluation kit available part temp range pin-package max3107eag+t -40 n c to +85 n c 24 ssop max3107etg+t -40 n c to +85 n c 24 tqfn-ep* max3107etg/v+t -40 n c to +85 n c 24 tqfn-ep*
2 ______________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos table of contents absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 package thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 dc electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 ac electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 test circuits/timing diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 typical operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 pin configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 register map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 register set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 receive and transmit fifos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 transmitter operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 receiver operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 line noise indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 clocking and baud-rate generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 crystal oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 external clock source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 pll and predivider . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 fractional baud-rate generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2x and 4x rate modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 multidrop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 auto data filtering in multidrop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 auto transceiver direction control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 echo suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 auto hardware flow control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 autorts control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 autocts control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 auto software (xon/xoff) flow control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 transmitter flow control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 receiver flow control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 fifo interrupt triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 low-power standby modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 forced sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 autosleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 shutdown mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
_______________________________________________________________________________________ 3 max3107 spi/i 2 c uart with 128-word fifos power-up and irq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 interrupt structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 interrupt enabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 interrupt clearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 detailed register descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 serial controller interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 spi interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 spi single-cycle access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 spi burst access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 i 2 c interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 start, stop, and repeated start conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 slave address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 bit transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 single-byte write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 burst write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 single-byte read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 burst read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 applications information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 startup and initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 low-power operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 interrupts and polling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 logic-level translation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 connector pin sharing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 rs-232 5x3 application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 typical application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 chip information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 functional diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 table of contents ( continued )
4 ______________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos list of figures figure 1. i 2 c timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 figure 2. spi timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 figure 3. transmit fifo signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 figure 4. receive data format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 figure 5. midbit sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 figure 6. receive fifo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 figure 7. clock selection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 figure 8. 2x and 4x baud rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 figure 9. auto transceiver direction control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 figure 10. setup and hold times in auto transceiver direction control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 figure 11. half-duplex with echo suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 figure 12. echo suppression timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 figure 13. simplified interrupt structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 figure 14. pll signal path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 figure 15. spi single-cycle read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 figure 16. spi single-cycle write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 figure 17. i 2 c start, stop, and repeated start conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 figure 18. write byte sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 figure 19. burst write sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 figure 20. read byte sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 figure 21. burst read sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 figure 22. acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 figure 23. startup and initialization flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 figure 24. logic-level translation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 figure 25. connector sharing with a usb transceiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 figure 26. rs-232 application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 figure 27. rs-485 half-duplex application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 list of tables table 1. stopbits truth table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 table 2. length[1:0] truth table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 table 3. swflow[3:0] truth table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 table 4. pllfactor[1:0] selection guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 table 5. i 2 c address map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
_______________________________________________________________________________________ 5 max3107 spi/i 2 c uart with 128-word fifos list of registers rhrreceiver hold register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 thrtransmit hold register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 irqenirq enable register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 isrinterrupt status register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 lsrintenline status register interrupt enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 lsrline status register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 spclchrintenspecial character interrupt enable register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 spclcharintspecial character interrupt register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 stsintensts interrupt enable register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 stsintstatus interrupt register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 mode1 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 mode2 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 lcrline control register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 rxtimeoutreceiver timeout register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 hdplxdelay register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 irda register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 flowlvlflow level register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 fifotrglvlfifo interrupt trigger level register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 txfifolvltransmit fifo level register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 rxfifolvlreceive fifo level register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 flowctrlflow control register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 xon1 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 xon2 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 xoff1 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 xoff2 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 gpioconfggpio configuration register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 gpiodatagpio data register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 pllconfigpll configuration register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 brgconfigbaud-rate generator configuration register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 divlsbbaud-rate generator lsb divisor register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 divmsbbaud-rate generator msb divisor register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 clksourceclock source register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 revidrevision identification register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
6 ______________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. (voltages referenced to agnd.) v l , v a , v ext , xin ................................................ -0.3v to +4.0v v 18 , xout .................................................. -0.3v to (v a + 0.3v) rst , irq , din/a1, cs /a0, sclk/scl, dout/sda, ldoen, i 2 c /spi .................. -0.3v to (v l + 0.3v) tx, rx, rts /clkout, cts , gpio_ ....... -0.3v to (v ext + 0.3v) dgnd .................................................................. -0.3v to +0.3v continuous power dissipation (t a = +70 n c) tqfn (derate 15.4mw/ n c above +70 n c) ................. 1229mw ssop (derate 12.3mw/ n c above +70 n c) ................... 988mw operating temperature range ........................ -40 n c to +85 n c junction temperature ................................................... +150 n c storage temperature range ........................... -65 n c to +150 n c lead temperature (soldering, 10s) ................................ +300 n c soldering temperature (reflow) ...................................... +260 n c dc electrical characteristics (v a = +2.35v to +3.6v, v l = +1.71v to +3.6v, v ext = +1.71v to +3.6v, t a = -40 n c to +85 n c, unless otherwise noted. typical values are at v a = +2.8v, v l = +1.8v, v ext = +2.5v, t a = +25 n c.) (note 2) absolute maximum ratings tqfn junction-to-ambient thermal resistance ( b ja ) .......... 65 n c/w junction-to-case thermal resistance ( b jc ) ............... 15 n c/w ssop junction-to-ambient thermal resistance ( b ja ) ........... 81 n c/w junction-to-case thermal resistance ( b jc ) ............... 32 n c/w note 1: package thermal resistances were obtained using the method described in jedec specification jesd51-7, using a four- layer board. for detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial . package thermal characteristics (note 1) parameter symbol conditions min typ max units digital interface supply voltage v l 1.71 3.6 v analog supply voltage v a 2.35 3.6 v uart interface logic supply voltage v ext 1.71 3.6 v logic supply voltage v 18 1.65 1.80 1.95 v current consumption v a supply current i a 1.8mhz crystal oscillator active, pll dis - abled, v ldoen = v l, spi/i 2 c interface idle 220 500 f a baud rate = 1mbps, external clock, spi frequency is 8mhz, external loopback pll disabled, v ldoen = v l (note 3) 0.65 1.3 ma v a shutdown supply current i a, shdn shutdown mode, v ldoen = 0v, v rst = 0v, all inputs and outputs are idle 20 35 f a v a sleep supply current i a, sleep sleep mode, v ldoen = v l , v rst = v l, all inputs and outputs are idle 45 100 f a v l supply current i l all logic inputs are at v l or v ext or 0v 4 15 f a v ext supply current i ext all logic inputs are at v l or v ext or 0v 5 10 f a v 18 input power-supply current in shutdown mode i 18shdn v ldoen = 0v (v 18 is powered by an exter - nal 1.85v voltage source), static power consumption 7 50 f a
_______________________________________________________________________________________ 7 max3107 spi/i 2 c uart with 128-word fifos dc electrical characteristics ( continued ) (v a = +2.35v to +3.6v, v l = +1.71v to +3.6v, v ext = +1.71v to +3.6v, t a = -40 n c to +85 n c, unless otherwise noted. typical values are at v a = +2.8v, v l = +1.8v, v ext = +2.5v, t a = +25 n c.) (note 2) parameter symbol conditions min typ max units sclk/scl, dout/sda dout/sda output low voltage in i 2 c mode v ol,i2c i load = -3ma, v l > 2v 0.4 v i load = -3ma, v l < 2v 0.2 x v l v dout/sda output low voltage in spi mode v ol,spi i load = -2ma 0.4 v dout/sda output high voltage in spi mode v oh,spi i load = 2ma v l - 0.4 v input low voltage v il spi and i 2 c mode 0.3 x v l v input high voltage v ih spi and i 2 c mode 0.7 x v l v input hysteresis v hyst spi and i 2 c mode 0.05 x v l v input leakage current i il v in = 0 to v l, spi and i 2 c mode -1 +1 f a input capacitance c in_i2c_spi spi and i 2 c mode 5 pf i2c /spi, cs /a0, din/a1 inputs input low voltage v il spi and i 2 c mode 0.3 x v l v input high voltage v ih spi and i 2 c mode 0.7 x v l v input hysteresis v hyst spi and i 2 c mode 50 mv input leakage current i il v in = 0 to v l, spi and i 2 c mode -1 +1 f a input capacitance c in_i2c_spi spi and i 2 c mode 5 pf irq output (open drain ) output low voltage v ol i load = -2ma 0.4 v output leakage i lk v irq = 0 to v l, irq is not asserted -1 +1 f a ldoen and rst inputs input low voltage v il 0.3 x v l v input high voltage v ih 0.7 x v l v input hysteresis v hyst 50 mv input leakage current i in v in = 0 to v l -1 +1 f a rts /clkout and tx outputs output low voltage v ol i load = -2ma 0.4 v output high voltage v oh i load = 2ma v ext - 0.4 v input leakage current i in output three-stated, v in = 0 to v ext -1 +1 f a input capacitance c in_irstb high-z mode 5 pf rx, cts inputs input low voltage v il 0.3 x v ext v input high voltage v ih 0.7 x v ext v input hysteresis v hyst 50 mv cts input leakage current i in_ cts v in = 0 to v ext -1 +1 f a rx pullup current i in_rx v in = 0v 0.3 1.5 3 f a input capacitance c in_iuart 5 pf gpio_ outputs and inputs output low voltage v ol i load = -2ma, push-pull or open drain 0.4 v output high voltage v oh i load = 2ma, push-pull v ext - 0.4 v
8 ______________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos dc electrical characteristics ( continued ) (v a = +2.35v to +3.6v, v l = +1.71v to +3.6v, v ext = +1.71v to +3.6v, t a = -40 n c to +85 n c, unless otherwise noted. typical values are at v a = +2.8v, v l = +1.8v, v ext = +2.5v, t a = +25 n c.) (note 2) ac electrical characteristics (v a = +2.35v to +3.6v, v l = +1.71v to +3.6v, v ext = +1.71v to +3.6v, t a = -40 n c to +85 n c, unless otherwise noted. typical values are at v a = +2.8v, v l = +1.8v, v ext = +2.5v, t a = +25 n c.) (note 2) parameter symbol conditions min typ max units input low voltage v il configured as an input 0.4 v input high voltage v ih configured as an input 2/3 x v ext v pulldown current i pd gpio_ = v ext 0.25 1 2.5 f a input capacitance c in_iuart configured as an input 5 pf xin input low voltage v il 0.3 v input high voltage v ih 1.2 v a v input capacitance c xi 16 pf xout input capacitance c xo 16 pf parameter symbol conditions min typ max units uart clocking external crystal frequency f xosc 1 4 mhz external clock frequency f clk 0.5 35 mhz external clock duty cycle (note 3) 45 55 % baud-rate generator clock input f ref (note 3) 96 mhz i 2 c bus: timing characteristics (see figure 1) scl clock frequency f scl standard mode 100 khz fast mode 400 bus free time between a stop (p) and start (s) condition t buf standard mode 4.7 f s fast mode 1.3 hold time for start (s) condition and repeated start (sr) condition (note 3) t hd:sta standard mode 4.0 f s fast mode 0.6 low period of the scl clock t low standard mode 4.7 f s fast mode 1.3 high period of the scl clock t high standard mode 4.0 f s fast mode 0.6 data hold time t hd:dat standard mode 0 0.9 f s fast mode 0 0.9
_______________________________________________________________________________________ 9 max3107 spi/i 2 c uart with 128-word fifos ac electrical characteristics ( continued ) (v a = +2.35v to +3.6v, v l = +1.71v to +3.6v, v ext = +1.71v to +3.6v, t a = -40 n c to +85 n c, unless otherwise noted. typical values are at v a = +2.8v, v l = +1.8v, v ext = +2.5v, t a = +25 n c.) (note 2) note 2: all devices are production tested at t a = +25 n c. specifications over temperature are guaranteed by design. note 3: not production tested. guaranteed by design. note 4: when v 18 is powered by an external voltage regulator, the external power supply must have current capability above or equal to i 18 . note 5: c b is the total capacitance of either the clock or data line of the synchronous bus in pf. parameter symbol conditions min typ max units data setup time t su:dat standard mode 250 ns fast mode 100 setup time for repeated start (sr) condition t su:sta standard mode 4.7 f s fast mode 0.6 rise time of sda and scl signals receiving t r standard mode (0.3 x v l to 0.7 x v l ) (note 5) 20 + 0.1c b 1000 ns fast mode (0.3 x v l to 0.7 x v l ) (note 5) 20 + 0.1c b 300 fall time of sda and scl signals t f standard mode (0.7 x v l to 0.3 x v l ) (note 5) 20 + 0.1c b 300 ns fast mode (0.7 x v l to 0.3 x v l ) (note 5) 20 + 0.1c b 300 setup time for stop (p) condition t su:sto standard mode 4.7 f s fast mode 0.6 capacitive load for sda and scl (note 3) c b standard mode 400 pf fast mode 400 i/o capacitance (scl, sda) c i/o 10 pf pulse width of spike suppressed t sp 50 ns spi bus: timing characteristics (see figure 2) sclk clock period t ch+cl 38.4 ns sclk pulse-width high t ch 16 ns sclk pulse-width low t cl 16 ns cs fall to sclk rise time t css 0 ns din hold time t dh 3 ns din setup time t ds 5 ns output data propagation delay t do 20 ns dout rise and fall times t ft 10 ns cs hold time t csh 32 ns
10 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos test circuits/timing diagrams figure 1. i 2 c timing diagram figure 2. spi timing diagram sda start condition (s) start condition (s) repeated start condition (sr) stop condition (p) scl t hd:sta t su:dat t su:sta t hd:dat t hd:sta t su:sto t r t f t buf t high t low t r t f cs sclk din dout t csh t css t cl t ds t dh t ch t do t csh
______________________________________________________________________________________ 11 max3107 spi/i 2 c uart with 128-word fifos typical operating characteristics (v a = 2.5v, v l = 2.5v, v ext = 2.5v, ldoen = v l , t a = +25 n c, unless otherwise noted.) gpio_ output low voltage vs. sink current (open drain) max3107 toc07 v ol (v) i sink (ma) 2 1 5 10 15 20 25 30 35 0 0 3 v ext = 3.3v v ext = 2.5v gpio_ output high voltage vs. source current (push-pull) max3107 toc06 v oh (v) i source (ma) 3.0 2.5 2.0 1.5 1.0 0.5 5 10 15 20 25 30 35 0 0 3.5 v ext = 3.3v v ext = 2.5v i a supply current vs. pll frequency max3107 toc05 pll frequency (mhz) i a (ma) 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 5.25 5.50 5.75 2.00 10 100 pll = x48 pll = x96 pll = x144 i a supply current vs. temperature max3107 toc04 temperature (c) i a (a) 60 35 10 -15 20 40 60 80 100 120 140 0 -40 85 external 3.6mhz clock baud rate = 115kbps v a = 3.3v v a = 2.5v i a supply current vs. v a voltage (external crystal, pll enabled) max3107 toc03 v a (v) i a (ma) 3.35 3.10 2.60 2.85 0.925 0.950 0.975 1.000 1.050 1.025 1.075 1.100 0.900 2.35 3.60 3.686mhz ext. crystal baud rate = 115kbps 6x pll mult.factor ldoen = v l ldoen = agnd 1.8v applied to v 18 i a supply current vs. v a voltage (external clock, pll enabled) max3107 toc02 v a (v) i a (ma) 3.35 3.10 2.85 2.60 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 2.0 2.35 3.60 external 614khz clock baud rate = 115kbps 6x pll mult.factor ldoen = v l ldoen = agnd 1.8v applied to v 18 i a supply current vs. v a voltage (external clock, pll disabled) max3107 toc01 v a (v) i a (a) 3.35 3.10 2.85 2.60 20 40 60 80 100 120 140 0 2.35 3.60 external 3.6mhz clock baud rate = 115kbps ldoen = v l ldoen = agnd 1.8v applied to v 18
12 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos pin configurations pin descriptions tqfn (3.5mm 3.5mm) max3107 19 20 21 22 1 2 3 4 5 6 18 17 16 15 14 13 23 24 12 11 10 9 8 7 tx xout v ext xin v a + v 18 i2c/spi ldoen dout/sda sclk/scl cs/a0 rx gpio3 gpio2 gpio1 agnd *ep *connect ep to agnd. gpio0 v l dgnd rst din/a1 irq cts top view 24 23 22 21 20 19 17 1 2 3 4 5 6 8 xout v ext tx rx v 18 v a agnd xin max3107 cts gpio2 sclk/scl ldoen 18 7 gpio3 dout/sda 15 10 gpio0 din/a1 16 9 gpio1 cs/a0 13 12 v l rst 14 11 dgnd irq i2c/spi ssop + rts/clkout rts/clkout pin name function tqfn-ep ssop 1 4 v 18 internal 1.8v ldo output and 1.8v logic supply input. bypass v 18 with a 1 f f ceramic capacitor to dgnd. keep v18 powered in shutdown mode. 2 5 i2c /spi spi or active-low i 2 c selector input. drive i2c /spi high to enable spi. drive i2c /spi low to enable i 2 c. 3 6 ldoen ldo enable input. drive ldoen high to enable the internal 1.8v ldo. drive ldoen low to disable the internal ldo. power v18 with an external 1.8v supply when ldoen is low. 4 7 dout/sda serial-data output. when i2c /spi is high, dout/sda functions as the dout spi serial-data output. when i2c /spi is low, dout/sda functions as the sda i 2 c serial- data input/output. 5 8 sclk/scl serial-clock input. when i2c /spi is high, sclk/scl functions as the sclk spi serial- clock input (up to 26mhz). when i2c /spi is low, sclk/scl functions as the scl i 2 c serial-clock input (up to 400khz). 6 9 cs /a0 active-low chip-select and address 0 input. when i2c /spi is high, cs /a0 functions as the cs spi active-low chip select. when i2c /spi is low, cs /a0 functions as the a0 i 2 c device address programming input. connect cs /a0 to dgnd or v l .
______________________________________________________________________________________ 13 max3107 spi/i 2 c uart with 128-word fifos pin descriptions (continued) pin name function tqfn-ep ssop 7 10 din/a1 serial-data and address 1 input. when i2c /spi is high, din/a1 functions as the din spi serial-data input. when i2c /spi is low, din/a1 functions as the a1 i 2 c device address programming input and connects to din/a1 dgnd or v l . 8 11 irq active-low interrupt open-drain output. irq is asserted when an interrupt is pending. 9 12 rst active-low reset input. drive rst low to force the uart into hardware reset mode. in hardware reset mode, the oscillator and the internal pll are shut down; there is no clock activity. 10 13 v l digital interface logic-level supply. v l powers the internal logic-level translators for rst , irq , din/a1, cs /a0, sclk/scl, dout/sda, ldoen, and i2c /spi. bypass v l with a 0.1 f f ceramic capacitor to dgnd. v l must be powered in all modes. 11 14 dgnd digital ground 12 15 gpio0 general-purpose input/output 0. gpio0 is user programmable as an input or output (push-pull or open drain). gpio0 has a weak pulldown resistor to ground. 13 16 gpio1 general-purpose input/output 1. gpio1 is user programmable as an input or output (push-pull or open drain). gpio1 has a weak pulldown resistor to ground. 14 17 gpio2 general-purpose input/output 2. gpio2 is user programmable as an input or output (push-pull or open drain). gpio2 has a weak pulldown resistor to ground. 15 18 gpio3 general-purpose input/output 3. gpio3 is user programmable as an input or output (push-pull or open drain). gpio3 has a weak pulldown resistor to ground. 16 19 cts active-low clear-to-send input. cts is a flow-control input. 17 20 rts /clkout active-low request-to-send output. rts /clkout can be set high or low by pro - gramming bit 7 ( rts ) of the lcr register. 18 21 rx receive input. serial uart data input. rx has an internal weak pullup resistor to v ext . 19 22 tx transmit output. serial uart data output. 20 23 v ext transceiver interface level supply. v ext powers the internal logic-level translators for rx, tx, rts , cts, and gpio_. bypass v ext with a 0.1 f f ceramic capacitor to dgnd. 21 24 xout crystal output. when using an external crystal, connect one end of the crystal to xout and the other to xin. when using an external clock source, leave xout unconnected. 22 1 xin crystal/clock input. when using an external crystal, connect one end of the crystal to xin and the other one to xout. when using an external clock source, drive xin with the external clock. 23 2 agnd analog ground 24 3 v a analog supply. v a powers the pll and internal ldo. bypass v a with a 0.1 f f ceram - ic capacitor to agnd. ep exposed paddle. connect ep to agnd. ep is not intended as an electrical connec - tion point. only for tqfn-ep package.
14 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos register map (all default reset values are 0x00, unless otherwise noted. all registers are r/w, unless otherwise noted.) * denotes nonzero default reset value: isr = 0x60, lcr = 0x05, fifotrglvl = 0xff, pllconfig = 0x01, divlsb = 0x01, clksource = 0x08, revid = 0xa1. ? denotes nonread/write value: rhr = r, thr = w, isr = cor, spclcharint = cor, stsint = r/cor, lsr = r, txfifolvl = r, rxfifolvl = r, revid = r. register addr bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 fifo data rhr ?* 0x00 rdata7 rdata6 rdata5 rdata4 rdata3 rdata2 rdata1 rdata0 thr ? 0x00 tdata7 tdata6 tdata5 tdata4 tdata3 tdata2 tdata1 tdata0 interrupts irqen 0x01 ctsien rxemtyien txemtyien txtrgien rxtrgien stsien spclchrien lsrerrien isr *? 0x02 ctsint rxemptyint txemptyint tfifotriglnt rfifotrigint stsint spcharint lsrerrint lsrinten 0x03 noiseinten rbreakien frameerrien parityien roverrien rtimoutien lsr *? 0x04 cts bit rxnoise rxbreak frameerr rxparityerr rxoverrun rtimeout spclchrinten 0x05 mltdrpinten breakinten xoff2inten xoff1inten xon2inten xon1inten spclcharint ? 0x06 multidropint breakint xoff2int xoff1int xon2int xon1int stsinten 0x07 sleepinten clkrdyinten gpi3inten gpi2inten gpi1inten gpi0inten stsint *? 0x08 sleepint clockready gpi3int gpi2int gpi1int gpi0int uart modes mode1 0x09 irqsel autosleep forcedsleep trnscvctrl rtshiz txhiz txdisabl rxdisabl mode2 0x0a echosuprs multidrop loopback specialchr rxemtyinv rxtriginv fiforst rst lcr * 0x0b rts txbreak forceparity evenparity parityen stopbits length1 length0 rxtimeout 0x0c timout7 timout6 timout5 timout4 timout3 timout2 timout1 timout0 hdplxdelay 0x0d setup3 setup2 setup1 setup0 hold3 hold2 hold1 hold0 irda 0x0e txinv rxinv mir sir irdaen fifo control flowlvl 0x0f resume3 resume2 resume1 resume0 halt3 halt2 halt1 halt0 fifotrglvl * 0x10 rxtrig3 rxtrig2 rxtrig1 rxtrig0 txtrig3 txtrig2 txtrig1 txtrig0 txfifolvl ? 0x11 txfl7 txfl6 txfl5 txfl4 txfl3 txfl2 txfl1 txfl0 rxfifolvl ? 0x12 rxfl7 rxfl6 rxfl5 rxfl4 rxfl3 rxfl2 rxfl1 rxfl0 flow control flowctrl 0x13 swflow3 swflow2 swflow1 swflow0 swflowen gpiaddr autocts autorts xon1 0x14 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 xon2 0x15 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 xoff1 0x16 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 xoff2 0x17 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 gpios gpioconfg 0x18 gp3od gp2od gp1od gp0od gp3out gp2out gp1out gp0out gpiodata 0x19 gpi3dat gpi2dat gpi1dat gpi0dat gpo3dat gpo2dat gpo1dat gpo0dat clock configuration pllconfig* 0x1a pllfactor1 pllfactor0 prediv5 prediv4 prediv3 prediv2 prediv1 prediv0 brgconfig 0x1b 4xmode 2xmode fract3 fract2 fract1 fract0 divlsb 0x1c div7 div6 div5 div4 div3 div2 div1 div0 divmsb 0x1d div15 div14 div13 div12 div11 div10 div9 div8 clksource * 0x1e clktorts - clocken pllbypass pllen crystalen revision revid *? 0x1f 1 0 1 0 0 0 0 1
______________________________________________________________________________________ 15 max3107 spi/i 2 c uart with 128-word fifos detailed description the max3107 uart is a bridge between an spi/ microwire? or i 2 c microprocessor bus and an asynchronous serial-data communication link, such as rs-485, rs-232, or irda. the max3107 contains an advanced uart, a fractional baud-rate generator, and four gpios. the max3107 is configured and monitored, and data is written and read from 8-bit registers through spi or i 2 c. these registers are organized by related function as shown in the register map . the host controller loads data into the transmit holding register (thr) through spi or i 2 c. this data is automati - cally pushed into the transmit fifo and sent out at tx. the max3107 adds start, stop, and parity bits to the data and sends the data out at the selected baud rate. the clock configuration registers determine the baud rate, clock source selection, and clock frequency prescaling. the receiver in the max3107 detects a start bit as a high-to-low rx transition. an internal clock samples this data. the received data is automatically placed in the receive fifo and can then be read out of the rxfifo through the rhr. register set the max3107 has a flat register structure without shad - ow registers. the registers are 8 bits wide. the max3107 registers have some similarities to the 16c550 registers. receive and transmit fifos the uarts receiver and the transmitter each have a 128-word deep fifo, reducing the intervals that the host processor needs to dedicate for high-speed, high-vol - ume data transfer. as the data rates of the asynchronous rx, tx interfaces increase and get closer to those of the host controllers spi/i 2 c data rates, uart management and flow control can make up a significant portion of the hosts activity. by increasing fifo size, the host is inter - rupted less often and can utilize spi/i 2 c burst data block transfers to/from the fifos. fifo trigger levels can generate interrupts to the host controller, signaling that programmed fifo fill levels have been reached. the transmitter and receiver trig - ger levels are programmed through fifotrglvl with a resolution of eight fifo locations. when a receive fifo trigger is generated, the host knows that the receive fifo has a defined number of words waiting to be read out or that a known number of vacant fifo locations are available and ready to be filled. the transmit fifo trig - ger generates an interrupt when the transmit fifo level is above the programmed trigger level. the host then knows to throttle data writing to the transmit fifo. the host can read out the number of words present in each of the fifos through the txfifolvl and rxfifolvl registers. transmitter operation figure 3 shows the structure of the transmitter with the txfifo. the transmit fifo can hold up to 128 words that are written to it through thr. the current number of words in the txfifo can be read out through the txfifolvl register. the transmit fifo can be programmed to generate an interrupt when a programmed number of words are present in the txfifo through the fifotrglvl register. the txfifo interrupt trigger level is selectable through fifotrglvl[3:0]. when the transmit fifo fill level reaches the programmed trig - ger level, the isr[4] interrupt is set. the transmit fifo is empty when isr[5]: txemtyint is set. isr[5] turns high when the transmitter starts transmit - ting the last word in the txfifo. hence, the transmitter is completely empty after isr[5] is set with an addi - tional delay equal to the length of a complete character (including start, parity, and stop bits). the contents of the txfifo and rxfifos are both cleared through mode2[1]: fiforst. figure 3. transmit fifo signals microwire is a trademark of national semiconductor corp. current fill level transmitter tx transmit fifo fifotrglvl[3:0] trigger isr[4] thr data from spi/i 2 c interface 128 3 2 1 level txfifolvl empty isr[5]
16 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos to halt transmission, set mode1[1]: txdisabl to 1. after mode1[1] is set, the transmitter completes transmission of the current character and then ceases transmission. the tx output logic can be inverted through irda[5]: txinv. if not stated otherwise, all transmitter logic described in this data sheet assumes irda[5] is 0. receiver operation the receiver expects the format of the data at rx to be as shown in figure 4. the quiescent logic state is a high and the first bit (the start bit) is logic-low. the receiver samples the data near the midbit instant (figure 4). the received words and their associated errors are depos - ited into the receive fifo. errors and status information are stored for every received word (figure 6). the host reads data out of the receive fifo through the receive holding register (rhr), oldest data first. the status information of the word previously read out of the rhr is located in the line status register (lsr). after a word is read out of the rhr, the lsr contains the status informa - tion for that word. the following three error conditions are determined for each received word: parity error, framing error, and noise on the line. line noise is detected by checking the consistency of the logic of the three samples (figure 5). the receiver can be turned off through mode1[0]: rxdisabl. when this bit is set to 1, the max3107 turns the receiver off immediately following the current word and does not receive any further data. the rx input logic can be inverted through irda[4]: rxinv. line noise indication when operating in standard (i.e., not 2x or 4x rate) mode, the max3107 checks that the binary logic level of the three samples per received bit are identical. if any of the three samples have differing logic levels, then noise on the transmission line has affected the received data and is considered to be noisy. this noise indication is reflected in the lsr[5]: rxnoise bit for each received byte. parity errors are another indication of noise, but are not as sensitive. clocking and baud-rate generation the max3107 can be clocked by an external crystal or an external clock source. figure 7 shows a simplified diagram of the clocking circuitry. when the max3107 is clocked by the crystal, the stsint[5]: clockready indicates when the clocks have settled and the baud-rate generator is ready for stable operation. the baud-rate clock can be routed to the rts /clkout output. the clock rate is 16x the baud rate in standard operating mode, and 8x the baud rate in 2x rate mode. in 4x rate mode, the clkout frequency is 4x the programmed baud rate. if the fractional portion of the baud-rate generator is used, the clock is not regular and exhibits jitter. figure 4. receive data format figure 5. midbit sampling received data lsb start d0 d1 d2 d3 d4 d5 d6 d7 parity stop stop msb midbit sampling 1 rx baud block 2 3 4 5 6 7 8 9 one bit period 10 11 majority center sampler 12 13 14 15 16 a
______________________________________________________________________________________ 17 max3107 spi/i 2 c uart with 128-word fifos crystal oscillator set clksource[4]: clocken to 1 and clksource[1]: crystalen to 1 to enable and select the crystal oscilla - tor. the on-chip crystal oscillator has load capacitances of 20pf integrated in both xin and xout. connect an external crystal or ceramic oscillator between xin and xout. external clock source when an external clock signal is used, this should be connected to xin. leave xout unconnected. set clksource[4]: clocken to 1 and clksource[1]: crystalen to 0 to select external clocking. pll and predivider the internal predivider and pll allow for a wide range of external clock frequencies and baud rates. the pll can be configured to multiply the input clock rate by a factor of 6, 48, 96, or 144 through pllconfig[7:6]. the predivider, located between the input clock and the pll, allows division of the input clock by a factor between 1 and 63 by writing to pllconfig[5:0]. see the pllconfig register description for more information. fractional baud-rate generator the internal fractional baud-rate generator provides a high degree of flexibility and high resolution in baud- rate programming. the baud-rate generator has a 16-bit integer divisor and a 4-bit word for the fractional divisor. the fractional baud-rate generator can be used with the external crystal or clock source. the integer and fractional divisors are calculated through the divisor, d: ref f d 16 baudrate = where f ref is the reference frequency input to the baud- rate generator and d is the ideal divisor. f ref must be less than 96mhz. in 2x and 4x rate modes, replace the divisor 16 by 8 or 4, respectively. the integer divisor portion, div, of the divisor, d, is obtained by truncating d: div = trunc(d) figure 6. receive fifo figure 7. clock selection diagram receive fifo fifotrglvl[7:4] trigger isr[3] word error 128 rxfifolvl 4 3 2 1 timeout empty errors overrun lsr[1] received data rhr receiver rx i 2 c/spi interface lsr[0] isr[6] lsr[5:2] current fill level crystal oscillator xout crystalen xin baud-rate generator clocken pllbyps pllen pll divider
18 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos div can be a maximum of 16 bits wide and is pro - grammed into the 2-byte-wide registers divmsb and divlsb. the minimum allowed for divlsb is 1. the fractional portion of the divisor, fract, is a 4-bit nibble, which is programmed into brgconfig[3:0]. the maximum value is 15, allowing the divisor to be pro - grammed with a resolution of 0.0625. fract is calcu - lated as: fract = round(16 x (d-div)) the following is an example of calculating the divisor. it is based on a required baud rate of 190kbaud and a reference input frequency of 28.23mhz and 1x (default) rate mode. the ideal divisor is calculated as: d = 28,230,000/(16 x 190,000) = 9.2861842105263157894736842105263 hence div = 9. fract = round(4.5789473684210526315789473684211) = 5 so that divmsb = 0x00, divlsb = 0x09, and brgconfig[3:0] = 0x05. the resulting (actual) baud rate can be calculated as: ref actual actual f br 16 d = for this example: d actual = 9 + 5/16 = 9.3125 where d actual = div + fract/16 and br actual = 28,230,000/(16 x 9.3125) = 189463.0872483221476510067114094 baud thus, the baud rate is within 0.28% of the ideal rate. 2x and 4x rate modes to support higher baud rates than possible with stan - dard (16x sampling) operation, the max3107 offers 2x and 4x rate modes. in this case, the reference clock rate only needs to be either 8x or 4x of the baud rate, respec - tively. the bits are only sampled once at the midbit instant instead of the usual three samples to determine the logic value of the bits. this reduces the tolerance to line noise on the received data. the 2x and 4x modes are selectable through brgconfig[5:4]. note that irda encoding and decoding does not operate in 2x and 4x modes. when 2x rate mode is selected, the actual baud rate is twice the rate programmed into the baud-rate genera - tor. if 4x rate mode is enabled, the actual baud rate on the line is quadruple that of programmed baud rate (figure 8). figure 8. 2x and 4x baud rates fractional rate generator f ref baud rate baudrateconfig[5:4] div[lsb] div[msb] note: irda does not work in 2x and 4x modes. fract 1x, 2x, 4x rate modes
______________________________________________________________________________________ 19 max3107 spi/i 2 c uart with 128-word fifos multidrop mode in multidrop mode, also known as 9-bit mode, the word length is 8 bits and a 9th bit is used for distinguishing between an address and a data word. multidrop mode is enabled through mode2[6]: multidrop. parity checking is disabled and an spclcharint[5]: multidropint interrupt is generated when an address (9th bit set) is received. it is up to the host processor to filter out the data intend - ed for its address. alternatively, the auto data-filtering mode can be used to automatically filter out the data intended for the stations specific 9-bit mode address. auto data filtering in multidrop mode in multidrop mode, the max3107 can be configured to automatically filter out data that is not meant for its address. the address is user-definable either by pro - gramming a register value or a combination of a register values and gpio hardware inputs. use either xoff2 or xoff2[7:4] in combination with gpio_ to define the address. enable multidrop mode by setting mode2[6]: multidrop to 1 and enable auto data filtering by setting mode2[4]: specialchr to 1. when using register bits in combination with gpio_ to define the address, the msb of the address is written to xoff2[7:4] register bits, while the lsbs of the address are defined through the gpios. to enable this mode, set flowctrl[2]: gpiaddr, mode2[4]: specialchr, and mode2[6]: multidrop to 1. gpio_ is automatically read when flowctrl[2]: gpiaddr is set to 1, and the address is updated on logic changes at gpio_. in the auto data-filtering mode, the max3107 auto - matically accepts data that is meant for its address and places this into the receive fifo, while it discards data that is not meant for its address. the received address word is not put into the fifo. auto transceiver direction control in some half-duplex communication systems, the trans - ceivers transmitter must be turned off when data is being received so as not to load the bus. this is the case in half-duplex rs-485 communication. similarly in full-duplex multidrop communication, like rs-485 or rs-422/v.11, only one transmitter can be enabled at any one time and the others must be disabled. the max3107 can automatically enable/disable a transceivers trans - mitter and/or receiver. this relieves the host processor of this time-critical task. the rts /clkout output is used to control the transceiv - ers transmit enable input and is automatically set high when the max3107s transmitter starts transmission. this occurs as soon as data is present in the transmit fifo. auto transceiver direction control is enabled through mode1[4]: trnscvctrl. figure 9 shows a typical max3107 connection in a rs-485 application. the rts /clkout output can be set high in advance of tx transmission by a programmable time period called the setup time (figure 10). the setup time is pro - grammed through hdplxdelay[7:4]. similarly, the rts / clkout signal can be held high for a programmable period after the transmitter has completed transmission. the hold time is programmed through hdplxdelay[3:0]. figure 9. auto transceiver direction control max3107 max13431 transmitter tx b a d rts/clkout rx txfifo receiver auto transceiver control rxfifo di ro re de r
20 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos echo suppression the max3107 can suppress echoed data, sometimes found in half-duplex communication (e.g., rs-485 and irda). if the transceivers receiver is not turned off while the transceiver is transmitting, copies (echoes) are received by the uart. the max3107s receiver can block the reception of this echoed data by enabling echo suppression. set mode2[7]: echosuprs to 1 to enable echo suppression. the max3107 receiver can block echoes with a long round trip delay. the transmitter can be configured to remain enabled after the end of transmission for a programmable period of time: the hold time delay. the hold time delay is set by the hdplxdelay[3:0] register. see the hdplxdelay description in the detailed register descriptions section for more information. auto transceiver direction control and echo suppression can operate simultaneously. auto hardware flow control the max3107 is capable of auto hardware ( rts and cts ) flow control without the need for host proces - sor intervention. when autorts control is enabled, the max3107 automatically controls the rts hand - shake without the need for host processor intervention. autocts flow control separately turns the max3107s transmitter on and off based on the cts input. autorts and autocts flow control are independently enabled through flowctrl[1:0]. autorts control autorts flow control ensures that the receive fifo does not overflow by signaling to the far-end uart to stop data transmission. the max3107 does this automati - cally by controlling rts /clkout. autorts flow control is enabled through flowctrl[0]: autorts. the halt and resume levels determine the threshold levels at which rts /clkout is asserted and deasserted. halt and figure 10. setup and hold times in auto transceiver direction control figure 11. half-duplex with echo suppression tx first character last character rts/clkout setup hold max3107 max13431 transmitter tx b a d rx txfifo receiver echo suppression rxfifo di ro re de r rts/clkout
______________________________________________________________________________________ 21 max3107 spi/i 2 c uart with 128-word fifos resume are programmed in flowlvl. with differing halt and resume levels, hysteresis can be defined for the rts /clkout transitions. when the rxfifo fill level reaches the halt level (flowlvl[3:0]), the max3107 deasserts rts /clkout. rts /clkout remains deasserted until the rxfifo is emptied and the number of words falls to the resume level. interrupts are not generated when the halt and resume levels are reached. this allows the host control - ler to be completely disengaged from rts flow control management. autocts control when autocts flow control is enabled, the uart auto - matically starts transmitting data when the cts input is logic-level low and stops transmitting when cts is logic- high. this frees the host processor from managing this timing-critical flow-control task. autocts flow control is enabled through flowctrl[1]: autocts. during autocts flow control the cts interrupt works normally. set the irqen[7]: ctsinten to 0 to disable cts interrupts; then isr[7]: ctsint is fixed to logic 0 and the host does not receive interrupts from cts. if cts is set high during transmission, the max3107 completes transmission of the current word and halts transmission afterwards. turn the transmitter off by setting mode1[1] to 1 before enabling autocts control. auto software (xon/xoff) flow control when auto software flow control is enabled, the max3107 recognizes and/or sends predefined xon/xoff charac - ters to control the flow of data across the asynchronous serial link. auto flow works autonomously and does not involve host intervention, similar to auto hardware flow control. to reduce the chance of receiving corrupted data that equals a single-byte xon or xoff character, the max3107 allows for double-wide (16-bit) xon/xoff char - acters. xon and xoff are programmed into the xon1, xon2 and xoff1, xoff2 registers. flowctrl[7:3] are used for enabling and configuring auto software flow control. an isr[1] interrupt is generated when xon or xoff are received and details are found in spclcharint. the irq can be masked by setting irqen[1]: spclchrien to 0. software flow control consists of transmitter control and receiver overflow control, which can operate indepen - dently of each other. figure 12. echo suppression timing tx rx di to ro propagation delay hold delay stop bit rts/clkout
22 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos transmitter flow control if auto transmitter control (flowctrl[5:4]) is enabled, the receiver compares all received words with the xoff and xon characters. if a xoff is received, the max3107 halts its transmitter from sending further data. the receiver is not affected and continues reception. upon receiving an xon, the transmitter restarts sending data. the received xon and xoff characters are filtered out and are not put into the receive fifo, as they do not have significance to the higher layer protocol. an interrupt is not generated. turn the transmitter off (mode1[1]) before enabling transmitter control. receiver flow control if auto receiver overflow control (flowctrl[7:6]) is enabled, the max3107 automatically sends xoff and xon con - trol characters to the far-end uart to avoid receiver overflow. xoff1/xoff2 are sent when the receive fifo fill level reaches the halt value set in the flowlvl regis - ter. when the host controller reads data from the receive fifo to a level equal to the resume level programmed into the flowlvl register, xon1/xon2 are automatically sent to the far-end station to signal it to resume data transmission. if dual-character (xon1 and xon2/xoff1 and xoff2) flow control is selected, xon1/xoff1 are transmitted before xon2/xoff2. fifo interrupt triggering receive and transmit fifo fill-dependent interrupts are generated if fifo trigger levels are defined. when the number of words in the fifos reach or exceed a trigger level, as programmed in fifotrglvl, an isr[3] or isr[4] interrupt is generated. there is no relationship between the trigger levels and the halt or resume levels. the fifo trigger level can, for example, be used for a block data transfer, since it gives the host an indication when a given block size of data is available for readout in the teceive fifo or available for transfer to the transmit fifo. low-power standby modes the sleep and shutdown modes reduce power con - sumption during periods of inactivity. in both sleep and shutdown modes, the uart disables specific functional blocks to reduce power consumption. forced sleep mode in forced sleep mode, all uart-related on-chip clocking is stopped. the following are inactive: the crystal oscilla - tor, the pll, the predivider, the receiver, and the transmitter. the spi/i 2 c interface and the registers remain active. thus, the host controller can access the resisters. to enter sleep mode, set mode1[5] to 1. to wake up, set mode1[5] to 0. autosleep mode the max3107 can be configured to operate in autosleep mode by setting mode1[6] to 1. in autosleep mode, the max3107 automatically enters sleep mode when all the following conditions are met: ? both fifos are empty. ? there are no pending irq interrupts. ? there is no activity on any input pins for a period equal to 65,536 uart characters lengths. the max3107 exits autosleep mode as soon as activity is detected on any of the gpio_, rx, or cts inputs. to manually wake up the max3107, set mode1[6] to 0. after wake-up is initiated, the internal clock starts up and a period of time is needed for clock stabilization. the stsint[5]: clockready bit indicates when the clocks are stable. if an external clock source is used, the stsint[5] bit does not indicate clock stability. shutdown mode shutdown mode is the lowest power consumption mode. in shutdown mode, all the max3107 circuitry is off. this includes the i 2 c/spi interface, the registers, the fifos, and clocking circuitry. the ldo is kept on. to enter shut - down mode, connect rst to dgnd. when the rst input is toggled high, the max3107 exits shut - down mode. when the max3107 sets irq to logic-high, the chip initialization is completed. the max3107 needs to be reprogrammed following a shutdown. keep v18 powered by the internal ldo or an external 1.8v supply during shutdown. power-up and irq irq has two functions. during normal operation (mode1[7] is 1), irq operates as a hardware interrupt output, where - by the irq is active when an interrupt is pending. an irq interrupt is only produced during normal operation, if at least one of the irqen interrupt enable bits are enabled. during power-up or following a reset, irq has a differ - ent function. it is held low until the max3107 is ready for programming following an initialization delay. once irq goes high, the max3107 is ready to be programmed. the mode1[7]: irqsel bit should then be set in order to enable normal irq interrupt operation. in polled mode, the revid register can be polled to check whether the max3107 is ready for operation. if the controller gets a valid response from revid, then the max3107 is ready for operation.
______________________________________________________________________________________ 23 max3107 spi/i 2 c uart with 128-word fifos bits 7C0: rdata[7:0] the rhr is the bottom of the receive fifo and is the register used for reading data out of the receive fifo. it contains the oldest (first received) character in the receive fifo. rhr[0] is the lsb of the character received at the rx input. it is the first data bit of the serial-data word received by the receiver. interrupt structure the structure of the interrupt is shown in figure 13. there are four interrupt source registers: isr, lsr, stsint, and spclcharint. the interrupt sources are divided into top- level and low-level interrupts. the top-level interrupts typically occur more often and can be read out directly through the isr. the low-level interrupts typically occur less often and their specific source can be read out through the lsr, stsint, or spclchar registers. the three lsbs of the isr point to the low-level interrupt registers that contain the source detail of the interrupt source. interrupt enabling every interrupt bit of the four interrupt registers can be enabled or masked through an associated interrupt enable register bit. these are the irqen, lsrinten, spclchrinten and stsinten registers. interrupt clearing when an isr interrupt is pending (i.e., any bit in isr is set) and the isr is subsequently read, the isr bits and irq are cleared. both the spclcharint and the stsint registers also are clear on read (cor). the lsr bits are only cleared when the source of the interrupt is removed, not when lsr is read. detailed register descriptions the max3107 has a flat register structure, without shad - ow registers, that makes programming and code simple and efficient. all registers are 8 bits wide. figure 13. simplified interrupt structure rhrreceiver hold register 7 6 5 4 3 2 1 0 isr 8 [7] irq power-up done mode1[7]: irqsel [0] low-level interrupts top-level interrupts 7 6 5 4 3 2 1 0 spclchrint 8 7 6 5 4 3 2 1 0 stsint 8 7 6 5 4 3 2 1 0 lsr 8 address: 0x00 mode: r bit 7 6 5 4 3 2 1 0 name rdata7 rdata6 rdata5 rdata4 rdata3 rdata2 rdata1 rdata0 reset x x x x x x x x
24 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos bits 7C0: tdata[7:0] the thr is the register that the host controller writes data to for subsequent uart transmission. this data is deposited in the transmit fifo. thr[0] is the lsb. it is the first data bit of the serial-data word that the transmitter sends out, right after the start bit. the irqen is used to enable the irq physical interrupt. any of the eight isr interrupt sources can be enabled to gener - ate an irq . the irqen bits only influence the irq output and do not have any effect on the isr contents or behavior. every one of the irqen bits operates on an isr bit. bit 7: ctsien the ctsien bit enables irq interrupt generation when the ctsint interrupt bit is set in the isr. set ctsien bit low to disable irq generation from ctsint. bit 6: rxemtyien the rxemtyien bit enables irq interrupt generation when the rxemtyint interrupt bit is set in the isr. set rxemtyien bit low to disable irq generation from rxemtyint. bit 5: txemtyien the txemtyien bit enables irq interrupt generation when the txemptyint interrupt bit is set in the isr. set txemtyien bit low to disable irq generation from txemptyint. bit 4: txtrgien the txtrgien bit enables irq interrupt generation when the tfifotrigint interrupt bit is set in the isr. set txtrgien bit low to disable irq generation from tfifotrigint. bit 3: rxtrgien the rxtrgien bit enables irq interrupt generation when the rfifotrigint interrupt bit is set in the isr. set rxtrgien bit low to disable irq generation from rfifotrigint. bit 2: stsien the stsien bit enables irq interrupt generation when the stsint interrupt bit is set in the isr. set stsien bit low to disable irq generation from stsint. bit 1: spclchrlen the spclchrien bit enables irq interrupt generation when the spcharint interrupt bit is set in the isr. set spclchrien bit low to disable irq generation from spcharint. thrtransmit hold register irqenirq enable register address: 0x00 mode: w bit 7 6 5 4 3 2 1 0 name tdata7 tdata6 tdata5 tdata4 tdata3 tdata2 tdata1 tdata0 address: 0x01 mode: r/w bit 7 6 5 4 3 2 1 0 name ctsien rxemtyien txemtyien txtrgien rxtrgien stsien spclchrien lsrerrien reset 0 0 0 0 0 0 0 0
______________________________________________________________________________________ 25 max3107 spi/i 2 c uart with 128-word fifos bit 0: lsrerrlen the lsrerrien bit enables irq interrupt generation when the lsrerrint interrupt bit is set in the isr[0]. set lsrerrien low to disable irq generation from lsrerrint. the isr provides an overview of all interrupts generated in the max3107. these interrupts are cleared on reading the isr. when the max3107 is operated in polled mode, the isr can be polled to establish the uarts status. in interrupt- driven mode, irq interrupts are enabled through the appropriate irqen bits. the isr contents give direct information on the cause for the interrupt or point to other registers that contain more detailed information. bit 7: ctsint the ctsint is set when a logic state transition occurs at the cts input. this bit is cleared after isr is read. the current logic state of the cts input can be read out through the lsr[7]: cts bit. bit 6: rxemptyint the rxemptyint is set when the receive fifo is empty. this bit is cleared after isr is read. its meaning can be inverted by setting the mode2[3]: rxemtyinv bit. bit 5: txemptyint the txemptyint bit is set when the transmit fifo is empty. this bit is cleared once isr is read. bit 4: tfifotriglnt the tfifotrigint bit is set when the number of characters in the transmit fifo is equal to or greater than the transmit fifo trigger level defined in fifotrglvl[3:0]. tfifotrigint is cleared when the transmit fifo level falls below the trigger level or after the isr is read. it can be used as a warning that the transmit fifo is nearing overflow. bit 3: rfifotriglnt the rfifotrigint bit is set when the receive fifo fill level reaches the receive fifo trigger level, as defined in the fifotrglvl[7:4]. this can be used as an indication that the receive fifo is nearing overrun. it can also be used to report that a known number of words are available which can be read out in one block. the meaning of rfifotrigint can be inverted through mode2[2]. rfifotrigint is cleared when isr is read. bit 2: stsint the stsint bit is set high when any bit in the stsint register that is enabled through a stsinten bit is high. the stsint bit is cleared on reading isr. bit 1: spcharlnt the spcharint bit is set high when a special character is received, a line break is detected, or an address character is received in multidrop mode. the cause for the spcharint interrupt can be read from the spclcharint register, if enabled through the spclchrinten bits. the spcharint interrupt is cleared when the isr is read. bit 0: lsrerrlnt the lsrerrint bit is set high when any lsr bits, which are enabled through the lsrinten, are set. this bit is cleared after the isr is read. isrinterrupt status register address: 0x02 mode: cor bit 7 6 5 4 3 2 1 0 name ctsint rxemptyint txemptyint tfifotrigint rfifotrigint stsint spcharint lsrerrint reset 0 1 1 0 0 0 0 0
26 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos the lsrinten allows routing of lsr interrupt bits to the isr[0]. bits 7 and 6: no function bit 5: noiseinten set the noiseinten bit high to enable routing the rxnoise interrupt to lsr[0]. if noiseinten is set low, rxnoise is not routed to lsr[0]. bit 4: rbreaklen set the rbreakien bit high to enable routing the rxbreak interrupt to lsr[0]. if rbreakien is set low, rxbreak is not routed to lsr[0]. bit 3: frameerrlen set the frameerrien bit high to enable routing the frameerr interrupt to lsr[0]. if frameerrien is set low, frameerr is not routed to lsr[0]. bit 2: paritylen set the parityien bit high to enable routing the rxparityerr interrupt to lsr[0]. if parityien is set low, rxparityerr is not routed to the lsr[0]. bit 1: roverrlen set the roverrien bit high to enable routing the rxoverrun interrupt to lsr[0]. if roverrien is set low, rxoverrun is not routed to lsr[0]. bit 0: rtimoutlen set the rtimoutien bit high to enabled routing the rtimeout interrupt to lsr[0]. if rtimoutien is set low, the rtimeout is not routed to lsr[0]. lsrintenline status register interrupt enable address: 0x03 mode: r/w bit 7 6 5 4 3 2 1 0 name noiseinten rbreakien frameerrien parityien roverrien rtimoutien reset 0 0 0 0 0 0 0 0
______________________________________________________________________________________ 27 max3107 spi/i 2 c uart with 128-word fifos the lsr shows all errors related to the word previously read out of the rxfifo. the lsr bits are not cleared upon a read; these bits stay set until the character with errors is read out of the rhr. the lsr also reflects the current state of the cts input. bit 7: cts bit the cts bit reflects the current logic state of the cts input. this bit is cleared when the cts input is low. following a power-up or reset, the logic state of the cts bit depends on the cts input. bit 6: no function bit 5: rxnoise if noise is detected on the rx input during reception of a character, the rxnoise bit is set for that character. the rxnoise bit indicates that there was noise on the line while the character most recently read from the rhr was received. the rxnoise flag can generate an isr[0] interrupt, if enabled through lsrinten[5]. bit 4: rxbreak if a line break (rx input low for a period longer than the programmed character duration) is detected, a break character is put in the rxfifo and the rxbreak bit is set for this character. a break character is represented by an all-zeros data character. the rxbreak bit distinguishes a regular character with all zeros from a break character. lsr[4] corresponds to the character most recently read from the rhr. the rxbreak flag can generate an isr[0] inter - rupt, if enabled through lsrinten[4]. bit 3: frameerr the frameerr bit is set high when the received data frame does not match the expected frame format in length. frameerr corresponds to the frame error of the character most recently read from the rhr. a frame error is related to errors in expected stop bits. the frameerr flag can generate an isr[0] interrupt, if enabled, through lsrinten[3]. bit 2: rxparityerr if the parity computed on the character being received does not match the received characters parity bit, the rxparityerr bit is set for that character. rxparityerr indicates a parity error for the word most recently read from the rhr. in 9-bit multidrop mode (mode2[6] = 1) the receiver does not check parity and the rxparityerr represents the 9th (i.e., address or data) bit. the rxparityerr flag can generate an isr[0] interrupt, if enabled through lsrinten[2]. bit 1: rxoverrun if the receive fifo is full and additional data is received that does not fit into the receive fifo, the rxoverrun bit is set. the receive fifo retains the data in it and discards all new data that does not fit into it. the rxoverrun indication is cleared after the lsr is read or the rxfifo level falls below its maximum. the rxoverrun flag can generate an isr[0] interrupt, if enabled through lsrinten[1]. lsrline status register address: 0x04 mode: r bit 7 6 5 4 3 2 1 0 name cts bit rxnoise rxbreak frameerr rxparityerr rxoverrun rtimeout reset x 0 0 0 0 0 0 0
28 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos bit 0: rtimeout the rtimeout bit indicates that stale data is present in the receive fifo. rtimeout is set when the youngest character resides in the rxfifo for longer than the period programmed into the rxtimeout register. the timeout counter restarts when at least one character is read out of the rxfifo or a new character is received by the rxfifo. if the value in rxtimeout is zero, rtimeout is disabled. rtimeout is cleared when a word is read out of the rxfifo or a new word is received. the rtimeout flag can generate an isr[0] interrupt, if enabled through lsrinten[0]. bits 7 and 6: no function bit 5: mltdrpinten the mltdrpinten bit enables routing the spclcharint[5]: multidropint interrupt to isr[1]. if mltdrpinten is set low (default), the multidropint is not routed to the isr[1]. bit 4: breakinten the breakinten bit enables routing the spclcharint[4]: breakint interrupt to isr[1]. if breakinten is set low (default), the breakint is not routed to the isr[1]. bit 3: xoff2inte the xoff2inten bit enables routing the spclcharint[3]: xoff2int interrupt to isr[1]. if xoff2inten is set low (default), the xoff2int is not routed to the isr[1]. bit 2: xoff1inten the xoff1inten bit enables routing the spclcharint[2]: xoff1int interrupt to isr[1]. if xoff1inten is set low (default), the xoff1int is not routed to the isr[1]. bit 1: xon2inten the xon2inten bit enables routing the spclcharint[1]: xon2int interrupt to isr[1]. if xon2inten is set low (default), the xon2int is not routed to the isr[1]. bit 0: xon1inten the xon1inten bit enables routing the spclcharint[0]: xon1int interrupt to isr[1]. if xon1inten is set low (default), the xon1int is not routed to the isr[1]. spclchrintenspecial character interrupt enable register address: 0x05 mode: r/w bit 7 6 5 4 3 2 1 0 name mltdrpinten breakinten xoff2inten xoff1inten xon2inten xon1inten reset 0 0 0 0 0 0 0 0
______________________________________________________________________________________ 29 max3107 spi/i 2 c uart with 128-word fifos bits 7 and 6: no function bit 5: multidropint the multidropint interrupt is set when the max3107 receives an address character in 9-bit multidrop mode (mode2[6] is 1). this bit is cleared when spclcharint is read. the spclcharint bit can be routed to isr[1] by enabling spclchrinten[5]. bit 4: breakint the breakint interrupt is set when a line break (rx low for longer than one character length) is detected by the receiver. this bit is cleared after spclcharint is read. the breakint interrupt can be routed to isr[1] by enabling spclchrinten[4]. bit 3: xoff2int the xoff2int interrupt bit is set when an xoff2 special character is received and special character detection is enabled, through mode2[4]. this interrupt is cleared upon reading spclcharint. the xoff2int interrupt can be routed to the isr[1] interrupt bit, if enabled through spclchrinten[3]. bit 2: xoff1int the xoff1int interrupt bit is set when an xoff1 special character is received and special character detection is enabled, through mode2[4]. this interrupt is cleared upon reading spclcharint. the xoff1int interrupt can be routed to the isr[1] interrupt bit, if enabled through spclchrinten[2]. bit 1: xon2int the xon2int interrupt bit is set when an xon2 special character is received and special character detection is enabled, through mode2[4]. this interrupt is cleared upon reading spclcharint. the xon2int interrupt can be routed to the isr[1] interrupt bit, if enabled through spclchrinten[1]. bit 0: xon1int the xon1int interrupt bit is set when an xon1 special character is received and special character detection is enabled, through mode2[4]. this interrupt is cleared upon reading spclcharint. the xon1int interrupt can be routed to the isr[1] interrupt bit, if enabled through spclchrinten[0]. spclcharintspecial character interrupt register address: 0x06 mode: cor bit 7 6 5 4 3 2 1 0 name multidropint breakint xoff2int xoff1int xon2int xon1int reset 0 0 0 0 0 0 0 0
30 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos bits 7 and 4: no function bit 6: sleepinten set the sleepinten bit high to route the sleepint status bit to the isr[2]: stsint. if set low, the stsinten masks the isr[2] bit from sleepint. bit 5: clkrdyinten set the clkrdyinten bit high to route the clockready status bit to the isr[2]: stsint bit. if set low, the clkrdyinten masks the isr[2] bit from the clockready status. bits 3C0: gpi[3:0]inten the gpi[3:0]inten bits that are set high route the associated stsint[3:0]: gpi[3:0]int bits to the isr[2] interrupt. gpi[3:0] inten bits that are set low, mask the isr[2] interrupt from the associated gpi[3:0]int bit. bits 7 and 4: no function bit 6: sleepint the sleepint bit is set when the max3107 enters sleep mode. the sleepint bit is cleared when the max3107 exits sleep mode. this status bit is cleared when the clock is disabled and cannot be cleared upon reading. the sleepint bit can generate an isr[2]: stsint interrupt, if enabled through stsinten[6]. bit 5: clockready the clockready bit is set high when the clock, the divider, and the pll have settled, and the max3107 is ready for data communication. the clockready bit only works with the crystal oscillator. it does not work with external clocking through xin. the clockready status bit is cleared when the clock is disabled and is not cleared upon read. this bit can generate an isr[2]: stsint interrupt, if enabled through stsinten[5]. bits 3C0: gpi[3:0]int the gpi[3:0]int interrupts are set high when a change of logic state occurs on the associated gpio_ input. gpi[3:0]int is cleared upon reading. these interrupts can be selectively routed to the isr[2] interrupt bit through the stsinten[3:0]. stsintensts interrupt enable register stsintstatus interrupt register address: 0x07 mode: r/w bit 7 6 5 4 3 2 1 0 name sleepinten clkrdyinten gpi3inten gpi2inten gpi1inten gpi0inten reset 0 0 0 0 0 0 0 0 address: 0x08 mode: r/cor bit 7 6 5 4 3 2 1 0 name sleepint clockready gpi3int gpi2int gpi1int gpi0int reset 0 0 0 0 0 0 0 0
______________________________________________________________________________________ 31 max3107 spi/i 2 c uart with 128-word fifos bit 7: irqsel depending on the logic level of the irqsel bit, irq has different meanings. after a hardware or software (mode2[0]) reset, the irqsel bit is set low and after a short delay, the irq output signals the end of the max3107s power-up sequence. the irq is low during power-up and transitions to high when the max3107 is ready to be programmed. irqsel can then be set high. in this case, irq becomes a regular interrupt output that signals pending interrupts, as indicated in the isr. details of the irqsel are described in the power-up and irq section. bit 6: autosleep set the autosleep bit high to set the max3107 to automatically enter low-power sleep mode after a period of no activ - ity (see the autosleep mode section). a stsint[6]: sleepint interrupt is generated when the max3107 goes to sleep or wakes up. bit 5: forcedsleep set the forcedsleep bit high to force the max3107 into low-power sleep mode (see the sleep mode section). the cur - rent sleep or wake state can be read out through this forcedsleep bit, even when the uart is in sleep mode. bit 4: trnscvctrl this bit enables the automatic transceiver direction control. set trnscvctrl high so that rts /clkout automatically controls the transceivers transmit/receive enable/disable inputs. setting trnscvctrl high sets rts /clkout low so that the transceiver is in receive mode. when the txfifo contains data available for transmission, the auto direction control sets rts /clkout high before the transmitter sends out the data. when the transmitter is empty, rts /clkout is automatically forced low again. setup and hold times of rts /clkout with respect to the tx output can be defined through the hdplxdelay register. a transmitter empty interrupt isr[5] is generated when the transmitter is empty. bit 3: rtshiz set the rtshiz bit high to three-state rts /clkout. bit 2: txhiz set the txhiz bit high to three-state the tx output. bit 1: txdisabl set the txdisabl bit high to disable transmission. if the txdisabl bit is set high during transmission, the transmitter com - pletes sending out the current character and then ceases transmission. data still present in the transmit fifo remains in the txfifo. the tx output is set to logic-high after transmission. bit 0: rxdisabl set the rxdisabl bit high to disable the receiver so that the receiver stops receiving data. all data present in the receive fifo remains in the rxfifo. mode1 register address: 0x09 mode: r/w bit 7 6 5 4 3 2 1 0 name irqsel autosleep forcedsleep trnscvctrl rtshiz txhiz txdisabl rxdisabl reset 0 0 0 0 0 0 0 0
32 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos bit 7: echosuprs set the echosuprs bit high so that the max3107s receiver gates any data it receives when its transmitter is busy transmitting. in half-duplex communication (like irda and rs-485) this allows blocking of the locally echoed data. the receiver can block data for an extended time after the transmitter ceases transmission by programming a hold time in hdplxdelay[3:0] bits. bit 6: multidrop set the multidrop bit high to enable the 9-bit multidrop mode. if this bit is set, parity checking is not performed by the receiver and parity generation is not done by the transmitter. the parity error bit, lsr[2], has a different meaning in this case. the parity error bit represents the 9th bit (address/data indication) that is received with each 9-bit character. bit 5: loopback set the loopback bit high to enable internal local loopback mode. this internally connects tx to rx and also rts / clkout to cts . in local loopback mode, the tx output and the rx output are disconnected from the internal transmit - ter and receiver. the tx output is in three-state. the rts output remains connected to the internal logic and reflects the logic state programmed in lcr[7]. the cts input is disconnected from rts and the internal logic. cts thus remains in a high-impedance state. bit 4: specialchr the specialchr bit enables special character detection. the receiver can detect up to four special characters, as selected in flowctrl:[5:4] and defined in the xon1, xon2, xoff1 and/or xoff2 registers, possibly in combination with gpio_ inputs, enabled through flowctrl[2]: gpiaddr. when a special character is received it is put into the rxfifo and a special character detect interrupt isr[1] is generated. special character detection can be used in addition to auto xon/xoff flow control, if enabled through flowctrl[3]. in this case xon/off flow control is then limited to single character xon and xoff and only two special characters can then be defined (in xon2 and xoff2). bit 3: rxemtyinv the rxemtyinv bit inverts the meaning of the receiver empty interrupt: isr[6]: rxemtyint. if rxemtyinv is set low (default state), the isr[6] interrupt is generated when the receive fifo is empty. if the rxemtyinv is set high, the isr[6] interrupt is generated when data is put into the empty receive fifo. bit 2: rxtriginv the rxtriginv bit inverts the meaning of the rxfifo triggering. when set, an isr[3]: rfifotrigint is generated when the rxfifo is emptied to the trigger level: fifotrglvl[7:4]. if the rxtrginv bit is low (default state), the isr[3] interrupt is generated when the rxfifo fill level that starts from a level below fifotrglvl[7:4] is filled up to the trigger level programmed into fifotrglvl[7:4]. bit 1: fiforst set the fiforst bit high to clear both the receive and transmit fifos of all data contents. after the fifo reset, the fiforst bit must then be set back to 0 to continue normal operation. bit 0: rst set the rst bit high to reset the max3107. the spi/i 2 c bus stays active during this reset, therefore, communication with the max3107 is possible. all register bits are reset to their reset state and all fifos are cleared. once set high, the rst bit must be cleared by writing a 0 to rst. mode2 register address: 0x0a mode: r/w bit 7 6 5 4 3 2 1 0 name echosuprs multidrop loopback specialchr rxemtyinv rxtriginv fiforst rst reset 0 0 0 0 0 0 0 0
______________________________________________________________________________________ 33 max3107 spi/i 2 c uart with 128-word fifos bit 7: rts the rts bit gives direct control of the rts /clkout output logic. if the rts bit is set high, then rts /clkout is set to logic-high. the rts bit only works if the clksource[7]:clktorts is not set high. bit 6: txbreak set txbreak to 1 to generate a line break whereby the tx output is held low until txbreak is set to 0. bit 5: forceparity forceparity enables forced parity, as used in 9-bit multidrop communication. set both lcr[3] and forceparity to use forced parity. the parity bit is forced high by the transmitter if lcr[4] low. the parity bit is forced low if lcr[4] is high. bit 4: evenparity set evenparity high to enable even parity. if evenparity is set low odd parity generation/checking is used. bit 3: parityen the parityen bit enables the use of a parity bit on the tx and rx interfaces. when parityen is low, then parity usage is disabled. when parityen is set to 1, the transmitter generates the parity bit as defined in lcr[4] and the receiver checks the received parity bit. bit 2: stopbits this defines the number of stop bits and depends on the length of the word programmed in lcr[1:0] (table 1). when stopbits is high and the word length is 5, the transmitter generates a word with a stop bit length equal to 1.5. under these conditions, the receiver recognizes a stop bit length greater than a 1-bit duration. bits 1 and 0: length[1:0] the length[1:0] bits configure the length of the words that the transmitter generates and the receiver checks for at the asynchronous tx and rx interfaces (table 2). lcrline control register table 1. stopbits truth table table 2. length[1:0] truth table address: 0x0b mode: r/w bit 7 6 5 4 3 2 1 0 name rts txbreak forceparity evenparity parityen stopbits length1 length0 reset 0 0 0 0 0 1 0 1 lcr[2] word length stop bit length 0 5, 6, 7, 8 1 1 5 1C1.5 1 6, 7, 8 2 length1 length0 word length 0 0 5 0 1 6 1 0 7 1 1 8
34 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos bits 7C0: timout[7:0] the receive data timeout bits allow programming a time delay after the last (newest) character in the receive fifo was received until a receive data timeout lsr[0] interrupt is generated. the duration is measured in character intervals and is dependent on the character length, parity, and stop bit setting and is inversely proportional to the baud rate. if the rxtimeout value equals zero, a timeout interrupt is not generated. the hdplxdelay register allows programming setup and hold times between rts /clkout and the tx output in auto transceiver direction control mode: mode1[4] is 1. the hold[3:0] time can also be used for echo suppression in half- duplex communication. hdplxdelay also functions in the 2x and 4x rate modes. bits 7C4: setup[7:4] the setupx bits define a setup time for rts /clkout to transition high before the transmitter starts transmission of its first character in auto transceiver direction control mode: mode1[4]. this allows the max3107 to account for skew dif - ferences of the external transmitters enable delay and propagation delays. setup[7:4] can also be used to fix a stable state on the transmission line prior to start of transmission. the unit of the hdplxdelay setup time delay is a 1-bit interval, making this delay baud-rate dependent. the maximum delay is 15-bit intervals. bits 3C0: hold[3:0] the hold[3:0] bits define a hold time for rts /clkout to be held stable (high) after the transmitter ends transmission of its last character in auto transceiver direction control mode: mode1[4]. rts /clkout turns low after the last stop bit was sent with a hold[3:0] delay. this keeps the external transmitter enabled during the hold duration. the second factor that the hold[3:0] bits define, is a delay in echo suppression mode, mode2[7]. see the echo suppression section for more information. the unit of the hdplxdelay hold time delay is a 1-bit interval, making the delay baud-rate dependent. the maximum delay is 15-bit intervals. rxtimeoutreceiver timeout register hdplxdelay register address: 0x0c mode: r/w bit 7 6 5 4 3 2 1 0 name timout7 timout6 timout5 timout4 timouto3 timout2 timout1 timout0 reset 0 0 0 0 0 0 0 0 address: 0x0d mode: r/w bit 7 6 5 4 3 2 1 0 name setup3 setup2 setup1 setup0 hold3 hold2 hold1 hold0 reset 0 0 0 0 0 0 0 0
______________________________________________________________________________________ 35 max3107 spi/i 2 c uart with 128-word fifos the irda allows selection of irda sir and mir-compliant pulse shaping at the tx and rx interfaces. it also allows inversion of the tx and rx logic, independently of whether irda is enabled or not. bits 7 and 6: no function bit 5: txinv set the txinv bit high to invert the logic at the tx output. this is independent of irda operation. bit 4: rxinv set the rxinv bit high to invert the logic state at the rx input. this is independent of irda operation. bit 3: mir set the mir and irdaen bits high to select irda 1.1 (mir) with 1/4 period pulse widths. bit 2: no function bit 2 must be kept logic 0. bit 1: sir set the sir bit and the irdaen bits high to select irda 1.0 pulses (sir) with 3/16th period pulses. bit 0: irdaen set the irdaen bit high so that irda-compliant pulses are produced at the tx output and the max3107 receiver expects such pulses at its rx input. if irdaen is set to low (default), normal (nonirda) pulses are generated and expected at the receiver. irdaen must be used in conjunction with the sir or mir select bits. flowlvl is used for selecting the rxfifo threshold levels used for software (xon/xoff) and hardware ( rts / cts ) flow control. bits 7C4: resume[7:4] resume[7:4] sets the transmit fifo threshold at which an xon is automatically sent or rts /clkout is automati - cally set low. this signals the far-end station to start transmission. the actual threshold level is calculated as 8 times resume[7:4]. the resulting level is in the range of 0 to 120. bits 3C0: halt[3:0] halt[3:0] sets a receive fifo threshold level at which an xoff is automatically sent or rts /clkout is automatically set high, depending on whether auto software or hardware flow control is enabled. this signals the far-end station to halt transmission. the actual threshold level is calculated as 8 times halt[3:0]. hence, the selectable threshold granularity is eight. the resulting level is in the range of 0 to 120. irda register flowlvlflow level register address: 0x0e mode: r/w bit 7 6 5 4 3 2 1 0 name txinv rxinv mir sir irdaen reset 0 0 0 0 0 0 0 0 address: 0x0f mode: r/w bit 7 6 5 4 3 2 1 0 name resume3 resume2 resume1 resume0 halt3 halt2 halt1 halt0 reset 0 0 0 0 0 0 0 0
36 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos bits 7C4: rxtrig[3:0] these 4 bits allow definition of the receive fifo threshold level at which an isr[3] interrupt is generated. this can be used to signal that the receive fifo is nearing overflow or that a predefined number of fifo locations are available for being read out in one block. the actual fifo trigger level is 8 times rxtrig[7:4], hence, the selectable threshold granularity is eight. bits 3C0: txtrig[3:0] these 4 bits allow definition of the transmit fifo threshold level at which the max3107 generates an isr[4] interrupt. this can be used to manage data flow to the transmit fifo. for example, if the trigger level is defined near the bottom of the txfifo, the host knows that a predefined number of fifo locations are available for being written to in one block. alternatively, if the trigger level is set near the top of the fifo, the host is warned when the transmit fifo is nearing overflow, if written to on a word-by-word basis. the actual fifo trigger level is 8 times txtrig[3:0], hence, the selectable threshold granularity is eight. bits 7C0: txfl[7:0] the txfifolvl register represents the current number of words in the transmit fifo. bits 7C0: rxfl[7:0] the rxfifolvl register represents the current number of words in the receive fifo. fifotrglvlfifo interrupt trigger level register txfifolvltransmit fifo level register rxfifolvlreceive fifo level register address: 0x10 mode: r/w bit 7 6 5 4 3 2 1 0 name rxtrig3 rxtrig2 rxtrig1 rxtrig0 txtrig3 txtrig2 txtrig1 txtrig0 reset 1 1 1 1 1 1 1 1 address: 0x11 mode: r bit 7 6 5 4 3 2 1 0 name txfl7 txfl6 txfl5 txfl4 txfl3 txfl2 txfl1 txfl0 reset 0 0 0 0 0 0 0 0 address: 0x12 mode: r bit 7 6 5 4 3 2 1 0 name rxfl7 rxfl6 rxfl5 rxfl4 rxfl3 rxfl2 rxfl1 rxfl0 reset 0 0 0 0 0 0 0 0
______________________________________________________________________________________ 37 max3107 spi/i 2 c uart with 128-word fifos bits 7C4: swflow[3:0] the swflow[3:0] bits configure auto software flow control and/or special character detection in combination with the characters defined in the xon1, xon2, xoff1 and/or xoff2 registers. see table 3. flowctrl[5:4] select which of the xon1, xon2, xoff1 or/and xoff2 characters are used for special character detec - tion and/or auto flow control. if auto receiver flow control is enabled through swflowen and flowctrl[7:6], the xon and xoff characters that the max3107 receives are filtered out and are not put into the rxfifo. set the swflowen bit to 0 and set mode2[4] to 1 to only enable special character detection. under these conditions, auto flow transmit flow control is not active. if both special character detection (mode2[4]) and auto software flow control (flowctrl[3]) are to be enabled, xon1 and xoff1 define the auto flow control characters, while xon2 and xoff2 define the special character detection characters. bit 3: swflowen the swflowen bit enables auto software flow control. the characters used for auto software flow control are selected in swflow[7:4]. if special character detection (mode2[4] set to 1) is used in addition to auto software flow control, xon1 and xoff1 are used for flow control, while xon2 and xoff2 define the special characters. bit 2: gpiaddr the gpiaddr bit, when set, enables that the four gpio_ inputs are used in conjunction with xoff2 for the definition of a special character. this can be used, for example, for defining the address of a rs-485 slave device through hardware. the gpio_ inputs logic levels, which define the 4 lsbs of the special character, while the 4 msbs are defined by the xoff2[7:4] bits. if gpiaddr is set, the contents of the xoff2[3:0] bits are neglected. in this case, the xoff2[3:0] bits, when read, also do not reflect the logic on gpio_. bit 1: autocts the autocts bit enables auto cts flow control by which the transmitter stops and starts sending data depending on the logic state at the cts input. see the auto hardware flow control section for a description of autocts flow con - trol. logic changes at the cts input result in an isr[7]: ctsint interrupt. the transmitter must be turned off by setting mode1[1] to 1 before autocts is enabled. bit 0: autorts the autorts bit enables auto rts flow control by which the max3107 sets its rts /clkout output dependent on the receive fifo fill level. the fifo thresholds at which rts /clkout changes state are set in flowlvl. see the auto hardware flow control section for more information. flowctrlflow control register address: 0x13 mode: r/w bit 7 6 5 4 3 2 1 0 name swflow3 swflow2 swflow1 swflow0 swflowen gpiaddr autocts autorts reset 0 0 0 0 0 0 0 0
38 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos the xon1 and xon2 register contents define the xon characters used for auto xon/xoff flow control and/or the special characters used for special character detection. see details in the flowctrl register description. bits 7C0: bit[7:0] these bits define the xon1 character if single-character xon auto software flow control is enabled in flowcntrl[7:4]. if double-character flow control is selected in flowcntrl[7:4], these bits constitute the lsb of the xon character. if special character detection is enabled in mode2[4] and auto flow control is not enabled, these bits define a special character. if special character detection and auto software flow control are enabled, xon1 defines the xon flow con - trol character. xon1 register table 3. swflow[3:0] truth table x = dont care address: 0x14 mode: r/w bit 7 6 5 4 3 2 1 0 name bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 reset 0 0 0 0 0 0 0 0 swflow3 swflow2 swflow1 swflow0 description receiver flow control transmitter flow control/special character detection 0 0 0 0 no flow control/no character detection. 0 0 x x no receiver flow control. 1 0 x x transmitter generates xon1, xoff1. 0 1 x x transmitter generates xon2, xoff2. 1 1 x x transmitter generates xon1, xon2, xoff1, and xoff2. x x 0 0 no transmitter flow control. x x 1 0 receiver compares xon1 and xoff1 and controls the transmitter accordingly. xon1 and xoff1 special character detection. x x 0 1 receiver compares xon2 and xoff2 and controls the transmitter accordingly. xon2 and xoff2 special character detection. x x 1 1 receiver compares xon1, xon2, xoff1, and xoff2 and controls the transmitter accordingly. xon1, xon2, xoff1, and xoff2 special character detection.
______________________________________________________________________________________ 39 max3107 spi/i 2 c uart with 128-word fifos the xon1 and xon2 register contents define the xon characters for auto xon/xoff flow control and/or the special characters used in special character detection. see details in the flowctrl register description. bits 7 C 0: bit[7:0] these bits define the xon2 character if single-character auto software flow control is enabled in flowcntrl[7:4]. if dou - ble-character flow control is selected in flowcntrl[7:4], these bits constitute the msb of the xon character. if special character detection is enabled in mode2[4], and auto software flow control is not enabled, these bits define a special character. if both special character detection and auto software flow control are enabled (mode2[4] and flowcntrl[3]), these bits define a special character. the xoff1 and xoff2 register contents define the xoff characters for auto xon/xoff flow control and/or the special characters used in special character detection. see details in the flowctrl register description. bits 7C0: bit[7:0] these bits define the xoff1 character if single-character xoff auto software flow control is enabled in flowcntrl[7:4]. if double character flow control is selected in flowcntrl[7:4], these bits constitute the lsb of the xoff character. if special character detection is enabled in mode2[4] and auto software flow control is not enabled, these bits define a special character. if special character detection and software flow control are both enabled, xoff1 defines the xoff flow control character. xon2 register xoff1 register address: 0x15 mode: r/w bit 7 6 5 4 3 2 1 0 name bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 reset 0 0 0 0 0 0 0 0 address: 0x16 mode: r/w bit 7 6 5 4 3 2 1 0 name bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 reset 0 0 0 0 0 0 0 0
40 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos the xoff1 and xoff2 register contents define the xoff characters for auto xon/xoff flow control and/or special characters used in special character detection. see details in the flowctrl register description. bits 7C0: bit[7:0] these bits define the xoff2 character if auto software flow control is enabled in flowcntrl[7:4]. if double-char - acter flow control is selected in flowcntrl[7:4], these bits constitute the msb of the xoff character. if special character detection is enabled in mode2[4] and auto flow control is not enabled, these bits define a special character. if both special character detection and auto flow control are enabled (mode2[4] and flowcntrl[3]), these bits define a special character. the four gpios can be configured as inputs or outputs and can be operated in push-pull or open-drain mode. the reference clock has to be active for the gpios to work. bits 7C4: gp[3:0]od set the gp[3:0]od bits to 1 to configure open-drain output or input operation. if gp[3:0]od are 0 (default), the gpio_are push-pull outputs, if configured as outputs in gpioconfg[3:0]. if configured as inputs in gpioconfg[3:0], the gpio_ are high-impedance inputs with weak pulldowns. bits 3C0: gp[3:0]out the gp[3:0]out bits configure the gpio_ to be inputs or outputs. set the gp[3:0]out bits high to configure the associ - ated gpio_ as outputs. the gp[3:0]out bits which are set low, are configured to be inputs. bits 7C4: gpi[3:0]dat the gpi[3:0]dat bits reflect the logic on gpio_ when configured as inputs through gpioconfg[3:0]. bits 3C0: gpo[3:0]dat the gpo[3:0]dat bits allows programming the logic state of the gpio_, when these are configured as outputs through gpioconfg[3:0]. for open-drain operation, pullup resistors are needed on gpio_. xoff2 register gpioconfggpio configuration register gpiodatagpio data register address: 0x17 mode: r/w bit 7 6 5 4 3 2 1 0 name bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 reset 0 0 0 0 0 0 0 0 address: 0x18 mode: r/w bit 7 6 5 4 3 2 1 0 name gp3od gp2od gp1od gp0od gp3out gp2out gp1out gp0out reset 0 0 0 0 0 0 0 0 address: 0x19 mode: r/w bit 7 6 5 4 3 2 1 0 name gpi3dat gpi2dat gpi1dat gpi0dat gpo3dat gpo2dat gpo1dat gpo0dat reset 0 0 0 0 0 0 0 0
______________________________________________________________________________________ 41 max3107 spi/i 2 c uart with 128-word fifos bits 7 and 6: pllfactor[1:0] the two pllfactor[1:0] bits allow programming the plls multiplication factor. the input and output frequencies of the pll have to be limited to the ranges shown in table 4. enable the pll through clksource[2]. bits 5C0: prediv[5:0] the six prediv[5:0] bits allow programming the divisor of the plls predivider. the divisor must be chosen such that the output frequency of the predivider, which equals the plls input frequency, is limited to the ranges shown in table 4. the input frequency of xin is f clk; f pllin = f clk /prediv (figure 4). prediv is an integer that must be in the range of 1 to 63. pllconfigpll configuration register table 4. pllfactor[1:0] selection guide figure 14. pll signal path predivider f clk pll f pllin f ref fractional baud-rate generator address: 0x1a mode: r/w bit 7 6 5 4 3 2 1 0 name pllfactor1 pllfactor0 prediv5 prediv4 prediv3 prediv2 prediv1 prediv0 reset 0 0 0 0 0 0 0 1 pllfactor1 pllfactor0 multiplication factor f pllin f ref min max min max 0 0 6 500khz 800khz 3mhz 4.8mhz 0 1 48 850khz 1.2mhz 40.8mhz 56mhz 1 0 96 425khz 1mhz 40.8mhz 96mhz 1 1 144 390khz 667khz 56mhz 96mhz
42 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos bits 7 and 6: no function bit 5: 4xmode when the 4xmode bit is set high, the max3107 baud rate is quadruple the regular (16x sampling) baud rate. the 2xmode bit should be set low if 4xmode is enabled. see the 2x and 4x rate modes section for more information. bit 4: 2xmode when the 2xmode bit is set high, the max3107 baud rate is double the regular (16x sampling) baud rate. see the 2x and 4x rate modes section for a detailed description. bits 3C0: fract[3:0] this is the fractional portion of the baud-rate generator divisor. set fract[3:0] to zero if not used. see the fractional baud-rate generator section for calculations. divlsb and divmsb define the baud-rate generator integer divisors. the minimum value is 1. see the fractional baud rate generator section for more information. bits 7C0: div[7:0] div[7:0] are the 8 lsbs of the integer divisor portion (div) of the baud-rate generator. bits 7C0: div[15:8] div[15:8] is the msb portion of the integer divisor (div). brgconfigbaud-rate generator configuration register divlsbbaud-rate generator lsb divisor register divmsbbaud-rate generator msb divisor register address: 0x1b mode: r/w bit 7 6 5 4 3 2 1 0 name 4xmode 2xmode fract3 fract2 fract1 fract0 reset 0 0 0 0 0 0 0 0 address: 0x1c mode: r/w bit 7 6 5 4 3 2 1 0 name div7 div6 div5 div4 div3 div2 div1 div0 reset 0 0 0 0 0 0 0 1 address: 0x1d mode: r/w bit 7 6 5 4 3 2 1 0 name div15 div14 div13 div12 div11 div10 div9 div8 reset 0 0 0 0 0 0 0 0
______________________________________________________________________________________ 43 max3107 spi/i 2 c uart with 128-word fifos bit 7: clktorts set the clktorts bit to 1 to route the baud-rate generator (16x baud rate) output clock to rts /clkout. the clock frequency is a factor of 16x, 8x, or 4x of the baud rate, depending on the brgconfig[5:4] settings. bits 6 and 5: no function bit 4: clocken set the clocken bit high to enable an external clocking (crystal or clock generator at xin). set the clocken bit to 0 to disable clocking. bit 3: pllbypass set the pllbypass bit high to enable bypassing the internal pll and predivider. bit 2: pllen set the pllen bit high to enable the internal pll. if pllen is set low, the internal pll is disabled. bit 1: crystalen set the crystalen bit high to enable the crystal oscillator. when using an external clock source at xin, crystalen must be set low. bit 0: no function always keep bit 0 at logic 0. bit 7C0: bit[7:0] the revid register indicates the revision number of the max3107 silicon, starting with 0xa1. this can be used during software development. clksourceclock source register revidrevision identification register address: 0x1e mode: r/w bit 7 6 5 4 3 2 1 0 name clktorts clocken pllbypass pllen crystalen reset 0 0 0 0 1 0 0 0 address: 0x1f mode: r bit 7 6 5 4 3 2 1 0 name bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 reset 1 0 1 0 0 0 0 1
44 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos serial controller interface the max3107 can be controlled through spi or i 2 c as defined by the logic on i2c /spi. see the pin configurations for further details. spi interface the spi supports both single-cycle and burst-read/write access. the spi master must generate clock and data signals in spi mode0 (i.e., with clock polarity cpol = 0 and clock phase cpha = 0). spi single-cycle access figure 15 shows a single-cycle read and figure 16 shows a single-cycle write. spi burst access burst access allows writing and reading in one block by only defining the initial register address in the spi com - mand byte. multiple characters can be loaded into the transmit fifo by using the thr (0x00) as the initial burst read address. similarly, multiple characters can be read out of the receiver fifo by using the rhr (0x00) as the spis burst read address. if the spi burst address is dif - ferent to 0x00, the max3107 automatically increments the register address after each spi data byte. efficient programming of multiple consecutive registers is thus possible. chip select, cs /a0, must be kept low during the whole cycle. the sclk/scl clock continues clocking throughout the burst access cycle. the burst cycle ends when the spi master pulls cs /a0 high. for example, writing 128 bytes into the txfifo can be achieved by a burst write access through the following sequence: ? pull cs /a0 low ? send spi write command ? send 128 byes ? release cs /a0 this takes a total of (1 + 128) x 8 clock cycles. i 2 c interface the max3107 contains an i 2 c-compatible interface for data communication with a host processor (scl and sda). the interface supports a clock frequency up to 400khz. scl and sda require pullup resistors that are connected to a positive supply. figure 15. spi single-cycle read figure 16. spi single-cycle write cs r a6 a5 a4 a3 a2 a1 a0 d7 d6 d5 d4 d3 d2 d1 d0 sclk sdi sdo a_ = register address d_ = 8-bit register contents cs w a6 a5 a4 a3 a2 a1 a0 d7 d6 d5 d4 d3 d2 d1 d0 sclk sdi a_ = register address d_ = 8-bit register contents
______________________________________________________________________________________ 45 max3107 spi/i 2 c uart with 128-word fifos start, stop, and repeated start conditions when writing to the max3107 using i 2 c, the master sends a start condition (s) followed by the max3107 i 2 c address. after the address, the master sends the register address of the register that is to be pro - grammed. the master then ends communication by issuing a stop condition (p) to relinquish control of the bus, or a repeated start condition (sr) to communicate to another i 2 c slave. see figure 17. slave address the max3107 includes a 7-bit slave address. the first 5 bits (msbs) of the slave address are factory-programmed and always 01011. these slave addresses are unique device ids. connect a1, a0 to ground or v l to set the i 2 c slave address (table 5). the address is defined as the 7 msbs followed by the read/write bit. set the read/ write bit to 1 to configure the max3107 to read mode. set the read/write bit to 0 to configure the max3107 to write mode. the address is the first byte of information sent to the max3107 after the start condition. bit transfer one data bit is transferred during each scl clock cycle. the data on sda must remain stable during the high period of the scl clock pulse. changes in sda while scl is high and stable are considered control signals (see the start, stop, and repeated start conditions section). both sda and scl remain high when the bus is not active. single-byte write with this operation the master sends an address and 1 or 2 data bytes to the slave device (figure 18). the write byte procedure is as follows: 1) the master sends a start condition. 2) the master sends the 7-bit slave id plus a write bit (low). 3) the addressed slave asserts an ack on the data line. 4) the master sends the 8-bit register address. 5) the active slave asserts an ack on the data line only if the address is valid (nack if not). 6) the master sends the 8-bit data byte. 7) the slave asserts an ack on the data line. 8) the master generates a stop condition. burst write with this operation the master sends an address and multiple data bytes to the slave device (figure 19). the burst write procedure is as follows: 1) the master sends a start condition. figure 17. i 2 c start, stop, and repeated start conditions table 5. i 2 c address map scl sda s sr p din/a1 cs /a0 read/ write i 2 c address 0 0 w 0x58 r 0x59 0 1 w 0x5a r 0x5b 1 0 w 0x5c r 0x5d 1 1 w 0x5e r 0x5f
46 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos 2) the master sends the 7-bit slave id plus a write bit (low). 3) the addressed slave asserts an ack on the data line. 4) the master sends the 8-bit register address. 5) the slave asserts an ack on the data line only if the address is valid (nack if not). 6) the master sends 8 bits of data. 7) the slave asserts an ack on the data line. 8) repeat steps 6 and 7 n - 1 times. 9) the master generates a stop condition. single-byte read with this operation the master sends an address and receives 1 or 2 data bytes from the slave device (figure 20). the read byte procedure is as follows: 1) the master sends a start condition. 2) the master sends the 7-bit slave id plus a write bit (low). 3) the addressed slave asserts an ack on the data line. 4) the master sends the 8-bit register address. 5) the active slave asserts an ack on the data line only if the address is valid (nack if not). 6) the master sends a repeated start (sr). figure 19. burst write sequence figure 20. read byte sequence figure 18. write byte sequence s device slave address - w a 8 data bits - 1 burst write a register address a 8 data bits - n a 8 data bits - 2 a from master to stave from slave to master p s sr device slave address - w a device slave address - r read single byte a register address a 8 data bits na from master to stave from slave to master p s p device slave address - w a 8 data bits from master to stave write single byte from slave to master a register address a
______________________________________________________________________________________ 47 max3107 spi/i 2 c uart with 128-word fifos 7) the master sends the 7-bit slave id plus a read bit (high). 8) the addressed slave asserts an ack on the data line. 9) the slave sends 8 data bits. 10) the master asserts a nack on the data line. 11) the master generates a stop condition. burst read with this operation the master sends an address and receives multiple data bytes from the slave device (figure 21). the burst read procedure is as follows: 1) the master sends a start condition. 2) the master sends the 7-bit slave id plus a write bit (low). 3) the addressed slave asserts an ack on the data line. 4) the master sends the 8-bit register address. 5) the slave asserts an ack on the data line only if the address is valid (nack if not). 6) the master sends a repeated start condition. 7) the master sends the 7-bit slave id plus a read bit (high). 8) the slave asserts an ack on the data line. 9) the slave sends 8 bits of data. 10) the master asserts an ack on the data line. 11) repeat steps 9 and 10 n - 1 times. 12) the master generates a stop condition. acknowledge data transfers are acknowledged with an acknowledge bit (ack) or a not-acknowledge bit (nack). both the master and the max3107 generate ack bits. to gener - ate an ack, pull sda low before the rising edge of the 9th clock pulse and keep it low during the high period of the 9th clock pulse (see figure 22). to generate a nack, leave sda high before the rising edge of the 9th clock pulse and keep it high for the duration of the 9th clock pulse. monitoring for nack bits allows for detection of unsuccessful data transfers. applications information startup and initialization the max3107 can be initialized following power-up or a hardware or software reset as shown in figure 23. to verify that the max3107 is ready for operation after a power-up or reset, check the irq output if interrupt driven operation is employed. in polled mode, repeatedly read a known register until the expected contents are returned. note that the con - tents of the revid change if new revisions of the product are released. if reading revid, it is recommended to only check for the most significant 4 bits: ah. figure 21. burst read sequence figure 22. acknowledge s sr device slave address - w a device slave address - r burst read a register address a 8 data bits - 1 a a 8 data bits - 3 8 data bits - 2 a 8 data bits - n a from master to stave from slave to master p not acknowledge acknowledge 1 2 8 9 sda scl s
48 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos low-power operation to reduce the power consumption during normal opera - tion, the following techniques can be adopted: ? do not use the internal pll. this saves the most power of the options listed here. disable and bypass the pll. with the pll enabled, the current to the v a supply is in the range of a few ma (depending on clock and multiplication factor), while it drops to below 1ma if disabled. ? keep the internal clock rates as low as possible. ? use low voltage on the v a supply. ? use an external 1.8v supply. this saves the power dissipated in the internal 1.8v linear regulator for the 1.8v logic supply. connect the external 1.8v supply to v 18 and disable the internal regulator by connecting ldoen to dgnd. interrupts and polling the host controller can manage and control the max3107 through polling and/or through interrupts. in polled mode, the irq physical interrupt output is not used and the host controller polls the isr register at frequent inter - vals to establish the state of the max3107. alternatively, the max3107s physical irq interrupt can be used to interrupt the host controller at specified events, making polling unnecessary. the irq output is an open-drain output that requires a pullup resistor to v l . logic-level translation the max3107 can be directly connected to transceivers and controllers that have different supply voltages. the v l input defines the logic voltage levels of the control - ler interface while the v ext voltage defines the logic of the transceiver interface. this ensures flexibility when selecting a controller and transceiver. figure 24 is an example of a setup when the controller, transceiver, and the max3107 are powered by three different supplies. figure 23. startup and initialization flowchart power-up/ rst input pulled high/ rst bit set low is irq high? or revid read successfully y n configure clocking configure modes configure fifo control configure flow control configure gpios start communication enable interrupts
______________________________________________________________________________________ 49 max3107 spi/i 2 c uart with 128-word fifos connector pin sharing the tx and rts /clkout outputs can be programmed to be high impedance. this can be used in cases where the max3107 shares a common connector with other communication devices. set the output of the max3107 to high impedance when the other communication devices are active. program mode1[2]: txhiz high to set tx to a high-impedance state. program mode1[3]: rtshiz high to set rts /clkout to a high-impedance state. figure 25 shows an example of connector sharing with a usb transceiver. rs-232 5x3 application the four gpios can be used to implement the other flow- control signals defined in itu v.24. figure 26 shows how the gpios create the dsr, dtr, dcd, and ri signals found on some rs-232/v.28 interfaces. set flowctrl[1:0] high to enable auto hardware rts / cts flow control. typical application circuit figure 27 shows the max3107 being used in a half- duplex rs-485 application. the microcontroller, the rs-485 transceiver, and the max3107 are powered by 3.3v. spi is used as the controllers communication interface. the max14840 receiver is continually enabled so that echoing occurs. enable auto echo suppression in the max3107 uart by setting mode2[7]: echosuprs to 1. set mode1[4]: transcvctrl high to enable auto trans - ceiver direction control to automatically control the de input of the transceiver. chip information process: bicmos figure 24. logic-level translation figure 25. connector sharing with a usb transceiver max3107 tx rx rts/clkout agnd dgnd v l v a v ext rst irq spi/i 2 c max3078 transceiver v cc di de ro v dd 2.5v 1.8v 3.3v microcontroller max3107 tx rx max13481e d+ d- oe tx/d+ rx/d- shared connector
50 _____________________________________________________________________________________ max3107 spi/i 2 c uart with 128-word fifos figure 26. rs-232 application figure 27. rs-485 half-duplex application max3107 tx rx tx rx spi/i 2 c max3245 t1in r1out microcontroller rst ldoen irq rts/clkout cts rts cts t2in r2out gpio0 gpio1 dtr dsr t3in r3out gpio2 gpio3 dcd ri r4out r5out max14840 a b di ro re de max3107 tx rx xout agnd v18 dgnd 100nf v ext v a v l irq spi/i 2 c ldoen rst xin spi 3.3v microcontroller clock rts 10k? 1 f 100nf
______________________________________________________________________________________ 51 max3107 spi/i 2 c uart with 128-word fifos functional diagram package information for the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages . note that a +, #, or - in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. max3107 logic-level translation spi/i 2 c tx and fifo ldo pll flow control logic-level translation registers and control rx and fifo fractional baud-rate generator gpio gpio0 rx cts gpio1 gpio2 gpio3 crystal oscillator tx v 18 v a dgnd agnd v ext v l ldoen i2c/spi din/a1 dout/sda cs/a0 sclk/scl rst irq xin xout divider rts/clkout package type package code outline no. land pattern no. 24 ssop a24+1 21-0056 90-0110 24 tqfn-ep t243a3+1 21-0188 90-0122
maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 52 maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ? 2011 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. max3107 spi/i 2 c uart with 128-word fifos revision history revision number revision date description pages changed 0 10/09 initial release 1 4/10 changed the maximum number for the external clock frequency specification from 30mhz to 35mhz in the ac electrical characteristics table 8 replaced the text in the spi burst access section 44 2 4/10 increased the maximum v il specification for the xin clock input in the electrical characteristics from 0.2v to 0.3v. 8 3 8/11 removed internal oscillator and updated register information; v18 capacitor increased to 1 f f; keep supplies powered during shutdown 1, 2, 6, 8, 11C18, 22, 24, 27, 30, 32, 35, 41, 43, 48C51

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