Peter,

I thanks for the info, but I don't see why the code should wait like that. I might as well be switching the IO line myself if I am going to all that trouble.

My point was, with the DJNZ the value sent on the serial port was different from when I didn't have DJNZ - and that the DJNZ should not make any different.

Aslo isn't you macro reliant on a specific clock speed? And why doesn't it set IT1 back again at the end?

Chris Brooks