Erik

"NOTE: most (all I know) '51s generate the TI interrupt/flag in the middle of the stop bit. It is ESSENTIAL to wait a bit of time (depending on transfer rate) before clearing DE. "


Didn't realise why the last byte was always corrupted, I have spent hours trying to find the cause of the problem and in the end just appended another character after my CRC and then ignored it at the other end (Modified Modbus Protocol so I know how long the message is), I will now go and fix this up - thanks for the tip

Marshall