application note mk5025 nrz to nrzi conversion the sgs-thomson mk5025 link level controller is a versatile device providing complete link level data communication control conforming to the 1984 version of ccitt x.25. the mk5035 also supports x .32 and x.75 as well as single channel lapd for isdn with its ui frames and extended addressing capabilities. the mk5025 also fea- tures a transparent mode of operation for imple- mentation of customized protocols using hdlc framing. the mk5025 serial interface consists of pins 25 - 27 and 29 - 31 (tclk, dtr/rts, rclk, and td, dsr/cts, rd respectively). the transmit data (td) is nrz encoded and the receive data (rd) is nrz decoded. to interface to other line code formats some conversion is necessary. the fol- lowing figure shows one method for doing nrz to nrzi conversion so that the mk5025 may be able to transmit and receive nrzi encoded data. it should be noted that the receive clock would typically be extracted from the received nrzi data, using a phase locked loop approach. AN492/0592 dq dff ck td (nrz) tclk transmit data (nrzi) d q dff ck d q dff ck received data (nrzi) receive clock [note: receive clock typically extracted from nrzi data] rd (nrz) rclk figure 1: nrz to nrzi conversion 1/2
information furnished is believed to be accurate and reliable. however, sgs-thomson microelectronics assumes no responsibility for the consequences of use of such information nor for any inf ringement of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any pat ent or patent rights of sgs-thomson microelectronics. specifications men- tioned in this p ubli cation are subject to change without notice. this publication supersedes and replaces all information previously supplied. sgs-thomson microelectronics products are not authorized for use as critical components in life support devices or systems without ex- press written approval of s gs-thomson microelectronics. ? 1995 sgs-thomson microelectronics - all rights reserved sgs-thomson microelectronics group of companies australia - brazil - france - germany - hong kong - italy - japan - korea - malaysia - malta - morocco - the netherlands - sing apore - spain - sweden - switzerland - taiwan - thaliand - united kingdom - u.s.a. application note 2/2
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