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Problem in synchronizing transmit section with receive section in p1021 QE

Question asked by Amanaganti VinodKumar on Feb 5, 2016
Latest reply on Feb 9, 2016 by alexander.yakovlev

Hi Alexander, All,


We are using P1021 rdb in our ISDN gateway. We are debugging V.35 interface, where we have to start sending data after start of reception.

We are using QE's UCC in transparent mode with NMSI configuration. As per QE reference manual by setting TXSY bit ensures that data transmission happens only after receive section starts taking data, but we are noticing that transmission happens as soon as it get CTS signal from other end party (even before CD is asserted). We probed the RTS, CTS, CD TXD and RXD lines with respect to clock signals and confirm the same.


We have few doubts on the GUMR register options.

1) Is there any option to invert the receive clock?

There is an option (tci) for inverting the Transmit clock, but no option available to invert the receive clock, how can we achieve this, could you please let us know whether it is possible or not?


2) CD and CTS lost error recovery

if we use CD and CTS in envelope mode, will UCC recovers itself after CD and CTS lost errors or need to configure Tx and Rx paths for next transmit and receive?


3) Doubt in CTSS, CDS options

According to me CTS, CD will be sampled on raising edge of the clock by UCC.


As per reference manual

if CDS is 0, the CD input is assumed to be asynchronous with the data. The UCC synchronizes it internally before data is received. (This mode is illegal in transparent mode when SYNL = 0b00.) Why is it illegal when SYNL= 0, could you please explain


if CTSS is 0, the CTS input is assumed to be asynchronous with the data. When it is internally synchronized by the UCC, data is sent after no more than two serial clock delays.


If UCC is sending at variable clocks (in between 0-2 clocks ) after CTS is asserted, how the other end party synchronize the data (without bit shift) that we are sending, Could you give an application example where this mode is used and how other end party synchronous with our transmission


We are using CTS, CD as asynchronous signals in our V.35 application and facing bit shifting issues, what is the combination that we should use for CDP, CDS, CTSP, and CTSS