Is it possible that I am driving a stepper motor (bi-polar) from Port 3 of the uC (AT89S51) and at the same time I am sending and receiving data serially from the pins 3.0 and 3.1 (not simultaneously, but one after the other)? Actually I want to send the data to some register from the PC using RS232 and then according to that data I want to drive the motor using L293D Driver connected to the same port (i.e. 3)...
what is the requirement. Are you running short of port pins. how many pins are you using. give more details. for stepper motor you connect driver for that, and parallely do you connect max232. How do you connect them.