I have tried to use the 2nd serial interface of the C166 I ve modified the hello-Program and created my own putchar.c but there is still no output in the 2nd serial window.
Your previous message does not give much for us to go on, a few things to check, Check the 2nd serial buffer for the characters your expecting. Put a breakpoint on the serial interrupt routine - check its being serviced. submit your code here and see if we can find a problem with it
Check your port DDR registers for correct initialisation Check also if the port is set into 'alternative' mode. If possible check with a scope for the baudrate, etc... Best Regards Paul
80C166 simulation is new in C166 V4.12. In this version all SFR including the 2nd serial interface are correctly simulated.