Please do post the host side code. In particular, have you set the port to raw mode? It may be cooking your data hence losing bytes. Try "stty -F /dev/ttyACM0 sane raw" before running your code (look at the stty manpage for other options)
Please do post the host side code. In particular, have you set the port to raw mode? It may be cooking your data hence losing bytes. Try "stty -F /dev/ttyACM0 sane raw" before running your code (look at the stty manpage for other options)