MD-7EM application note 1. module features -bluetooth v1.2 compliant -dual uart port -16-bit audio codec 2. specification -operating conditions supply voltage: 2.4 ? 3.6v temperature range: -20 ~ 70 -radio characteristics receiver sensitivity: -87dbm(typical) transmitter power: +16dbm(typical) 3. applications -stereo headphones -echo cancellation -automotive hands free kits -high performance telephony personal -enhanced audio applications 4. features -size (30 x 16.2 x 1.72 mm) -surface mountable -support pcm interface for sco -support kalimba dsp 5. descriptions MD-7EM is class 1 bluetooth stereo audio module for high perfor mance telephony headsets, enhanced audio applications, other a/v applications. it is designed to be used as a universal bluetooth module of bluetooth specification version 1.2 which can be deployed to implement versatile wireless applications such a s voice communications. the band-pass filt er and balun are integrated i nto the substrate.
6. block diagram 7. electrical characteristics absolute maximum ratings parameter min max unit temperature -20 70 supply voltage(v_pa) 3.2 3.4 v supply voltage(vdd) 2.4 3.6 v recommended operating conditions parameter min max unit supply voltage(v_pa 3.3 v supply voltage(vdd) 2.6 3.3 v
9. pin description pin no pin name description pad type 1 gnd common ground vss 2 v_pa power amp power supply v_pa 3 pio_2 programmable input/ou tput line bi-directional 4 pio_3 programmable input/ou tput line bi-directional 5 pio_8 programmable input/ou tput line bi-directional 6 pio_9 programmable input/ou tput line bi-directional 7 pio_10 programmable input/ou tput line bi-directional 8 pio_11 programmable input/ou tput line bi-directional 9 aio_1 programmable input/ou tput line bi-directional 10 aio_0 programmable input/ou tput line bi-directional 11 aud_out_lp speaker output po sitive (left channel) analogue 12 aud_out_ln speaker output ne gative(left channel) analogue 13 aud_out_rn speaker output nega tive(right channel) analogue 14 aud_out_rp speaker output posi tive(right channel) analogue 15 aud_in_lp audio signal input positive(left channel) analogue 16 aud_in_ln audio signal input n egative(left channel) analogue 17 aud_in_rp audio signal input positive(right channel) analogu e 18 aud_in_rn audio signal input negative(right channel) analogu e 19 vdd module power supply vdd 20 reset module reset input. reset if high>5ms to cause cmos in put 21 usb_dn usb data minus bi-directional 22 usb_dp usb data plus bi-directional 23 uart_rts uart request to s end active low cmos output 24 uart_cts uart clear to s end active low cmos input 25 uart_rx uart data input cmos input 26 uart_tx uart data output cmos output 27 pcm_in pulse code modulation synchronous data input cmos inp ut 28 pcm_sync pulse code modulation synchronous data sync bi-dire ctional 29 pcm_clk pulse code modulation s ynchronous data clk bi-direct ional 30 pcm_out pulse code modulation s ynchronous data output pcm ou tput 31 spi_mosi serial peripheral interface data input cmos input 32 spi_miso serial peripheral interface data output cmos output 33 spi_csb chip select for synchronous serial interface cmos in put
34 spi_clk serial peripheral in terface data clock cmos input 35 pio_7 programmable input/ou tput line bi-directional 36 pio_6 programmable input/ou tput line bi-directional 37 pio_5 programmable input/ou tput line bi-directional 38 pio_4 programmable input/ou tput line bi-directional 39 rf_in connect to antenna(for rf signal) analogue 40 gnd common ground vss 41 gnd common ground vss 42 gnd common ground vss 43 aio_3 programmable input/ou tput line bi-directional 44 gnd common ground vss 45 gnd common ground vss 46 gnd common ground vss 47 gnd common ground vss 10. uart interface MD-7EM is universal asynchronous receiver transmitter (uart) in terface provides a simple mechanism for communicating with other serial device u sing the rs232 standard. when MD-7EM is connected to another digital device, uart_rx and uart_tx transfer data between the two devices. the remaining two signal s, uart_cts, uart_rts, can be used to implement rs232 hardware flow control control where both are active low indicators. all uart connections are implemented using cmos technology and have signaling levels of 0v and vdd
11. pcm interface pulse code modulation (pcm) is a standard method used to digiti ze human voice patterns for transmission over digital communication channel. t hrough its pcm interface, MD-7EM has hardware support for continual transmissi on reception of pcm data, thus reducing processor overhead for wireless application . MD-7EM offers a bi- directional digital audio interf ace that route directly into th e baseband layer of the module firmware. it does not pas s through the hci protocol laye r. hardware on MD-7EM allows the data to be sent to the received f rom a sco connection. MD-7EM can be configured as pcm interface master generating an output clock of 128, 256 or 512khz. when configured as pcm interface slave it c an operated with input clock up to 2048khz. MD-7EM is compatible with a variety of clock formats, including long frame sync, short frame sync and gci timing envi ronments. it supports 13-bit or 16-bit liner, 8-bit u-law or a-law compan ied sample formats at 8k samples/s and can receive and transmit on any selection of t he first four slots following pcm_sync.
12. usb interface MD-7EM usb devices contain a full speed (12mbit/s) usb inter face that is capable of driving of a usb cable directly. no external usb transceiver is required. the device operates as s usb peripheral, responding to requests from a mas ter host controller such as a pc. both the ohci and uhci standards supported. the s et of the usb endpoints implemented behave as specification v1.2. as usb is master/slave oriented system (in common with other us b peripheral), md- 7em only supports usb slave operation. MD-7EM features an internal usb pull-up resistor. this pulls th e usb+ pin weakly high when MD-7EM is ready to enumerate. it signals to the pc th at it is a full speed (12mbit/s) usb device. 13. audio interface the audio interface circuit consists of audio codec, dual audi o inputs and outputs, and a pcm, i2s or spdif configurable interface v1.2. the codec supports stereo playback and recording of audio signa ls at multiple sample rates with a resolution of 16-bit. the adc and the dac of the c odec each contain two independent channels. any adc or dac channel can be run at its won independent sample rate. pcm interface spdif interface i2s interface pcm_out spdif_out sd_out pcm_in spdif_in sd_in pcm_sync ws pcm_clk sck
< alternative functions of the digital audio bus interface on the pcm interface> the audio input circuitry consists of a dual audio input that can be configured to be either single ended or fully differential and programmed for ei ther microphone or line input. it has a programmable gain stage for optimization of dif ferent microphones. the digital audio bus supports various digital bus standard, wh ich include i2s, and the interfaces contained within the iec 60958 specification such as spdif and aes3. 14. stereo audio interface . the main features of the interface are: -16-bit resolution, standard, sample rates of 8khz, 11.025khz, 16khz, 22.050khz, 32khz, 44.1khz and 48khz(dac only) -dual adc and dac for stereo audio. -integrated amplifiers for driving microphone and speakers with minimum external components -stereo and mono analogue input for voice band and audio band -stereo and mono analogue output f or voice band and audio band -support for stereo digital audi o bus standards such as i2s -support for iec-60958 standard stereo digital bus standards i. e. s/pdif and aes3ebu -support for pcm interfaces including pcm master codec that req uire an external system clock.
the stereo audio codec uses a fully differential architecture i n the analogue signal path, which results in low noise sensitivity and good power sup ply rejection while effectively doubling the signal amplitude. it operates from a s ingle power-supply of 1.8v and uses a minimum of external components. 14. pin map top view
15. dimension
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