Am facing problem while receiving file from PC as YMODEM protocol

[DGR.1]

Am facing problem while receiving file from PC as YMODEM protocol, Am just using ymodem.c an d ymodem.h file fromIAP library i have modified the code, but am not receiving Header packet only(SOH or STX), please help as soon as possible am struck here, currently am not writing data into flash as of now i just commented to verify the data first.

We are using STM32L431 MCU

please find the following code

[DGR.1]

Please any one faced same issue please reply as soon as possible, am not even getting first byte as SOH i have verified by step execution

[Tesla DeLorean]

Perhaps you can use winmerge or diff and figure out how to unfsk the code?

Code needs to be sending a periodic character, usually a 'C' or whatever, to indicate it is waiting for the source to initiate the transfer.

[Bob S]

Are you saying that you never receive ANY bytes? Or only that you never receive the SOH byte (but can receive other data)? You don't show your UART configuration code, and you don't say if this is custom hardware of one of ST's NUCLEO/DISCO boards (or some other commercial board). Have you verified that your UART works at all? Strip out the YModem code and just echo incoming UART data back out the UART. Does that work? If not, you've got UART config issues or hardware issues.

[DGR.1]

UART is working fine

[Pavel A.]

Do you use Teraterm?

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[DGR.1]

I have tried with both Teraterm and Hyper terminal

[Pavel A.]

AFAIK, Teraterm has a bug in Ymodem protocol. I could not make Ymodem examples provided by ST to work as is.

But you seem to have a more low-level issue.

-- pa

[DGR.1]

Hi Bob,

UART is working fie because first i have verified normal UART Rx TX operation from terminal, Am using custom design board not any dev or Nucleo board

[DGR.1]

Hello all,

Thank you for your response and your answers, am able to resolve the issue, the main thing is i missed the CRC poinomial and initial value initialization

thanks to all