In my project i use a 8051 (exactly C505) and a 16C550 external Uart but it did'nt work.

I write a testprogram and send some data to Pc and from PC to MCU -- this works without problems.

I foundout that in the install.a51 of the mon file the generated Bauddiv Value for the external Uart was 0, because the parser can't handle values bigger then 65535.

OK -- i correct this -- at this time Bauddiv has the correct value -- but nothing works again.

Has someone a tip or had have equal problems and know a solution?

I produce the mon51.hex with the install.bat 6 F6 80

mon51 works without problems if i use the internal uart.

I hope someone can help me to find a solution


Best regards
Paco


Ps.:
IO-Space for Uart is 0xE400 - 0xE7FF
P32(INT0) is for intrpt - pin used