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DGR.1
DGR.1
Associate
February 28, 2020
Question

Am facing problem while receiving file from PC as YMODEM protocol

  • February 28, 2020
  • 14 replies
  • 4291 views

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

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14 replies

DGR.1
DGR.1Author
Associate
February 28, 2020

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
Tesla DeLorean
Guru
February 28, 2020

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.

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Bob S
Bob S
Super User
February 28, 2020

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
DGR.1Author
Associate
March 2, 2020

UART is working fine

Pavel A.
Pavel A.
February 28, 2020

Do you use Teraterm?

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DGR.1
DGR.1Author
Associate
March 2, 2020

I have tried with both Teraterm and Hyper terminal

Pavel A.
Pavel A.
March 2, 2020

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
DGR.1Author
Associate
March 2, 2020

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
DGR.1Author
Associate
March 5, 2020

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

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