File transfer via serial port

Question

I am trying to send a file via serial port. I tried sending picocom commands in a bash script. However the device writes out a menu of options. When it gets to the file transfer step - it writes out 'C' until a file is sent, after which it does the handshake and proceeds with the transfer. With the script I am not able to send the keystrokes 'C-a' and 'C-s' to get the '*** file:' prompt of picocom. I can do it manually. I even tried a combination of bash and python and pyautogui for the keystrokes, bash echo command to send the hex version of the keystrokes. I even tried sending 'sz' commands through the script and stty. All of these attempts were unsuccessful.

So I switched to python, and tried the xmodem library in python. I am supposed to use ymodem. I thought the 'YMODEM batch transmission session' in the library would do the job. The modem.send command always errors out with the file not being sent.

Read Byte: b'C'
Put Byte: 133
Read Byte: b'C'
send error: expected ACK; got b'C' for block 1
Put Byte: 133
Read Byte: b'C'
send error: expected ACK; got b'C' for block 1

How can i get around this?

Answer 1

Finally ended up using a combination of python and bash - python for serial communication and for parsing the file names of the binaries, and, bash stty and sb commands for transferring the binaries.