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CDC USB receive with XMODEM

PKraj.1
Associate II

I'm using STM32F745. I would like to use the CDC USB to receive data from Tera Term using the XMODEM protocol. I can configure CDC_Receive_FS() to receive data for blocks of 64 bytes or less.  The procedure for this is well documented. XMODEM packets are 133 bytes. I can only reliably receive the first 64 bytes. It won't communicate at all if CDC_DATA_FS_MAX_PACKET_SIZE is increased beyond 64. How can I facilitate this?

4 REPLIES 4
Pavel A.
Evangelist III

CDC_DATA_FS_MAX_PACKET_SIZE is a constant, 64. It cannot be increased. Instead receive several packets.

PKraj.1
Associate II

The problem is that the subsequent packets are the same as the first. They never update.

If you type characters in teraterm, do you receive them correctly on stm32 side?

PKraj.1
Associate II

Yes, for the first 64 bytes.