I am trying to connect 89S52 and PICAXE18 using RS-232.
I can simulate connection with windows hyperterminal at 2400bps and both microcotrollers respond correctly but when I connect them together 89S52 sends a command but PICAXE18 does not respond. Why?
One possible reason can be that clocks of both microcontrtollers "don't match" and they both, or one of them - in this case PICAXE, can not read properly 2400bps strings ..
As PICAXE is clocked by internal RC-based generator you can use CALIBFREQ command and try to correct it ..
You will have +/-31 numbers to play with, where 0 is the default value ..