I was using Keil to program a Philips 89c51 chip last week to transmit data at 19200 bps. It was working perfectly, i got the data on the PC. I could also see the actual 0V - 5V waveforms on the TXD pin. This week I switched the chip to an Atmel 89c51 33 MHz one..using the same program but can't see thevoltages on the TXD pin. Tried putting a load resistor to ground, then I can see the voltages but the chip is now not speaking to my PC. Do I need to be doing something different..? thanks for all help..
ONCE MORE since you did not bother to state the whole derivative names Your question can not be answered based on generic names. Erik