I have a circuit that is well proven over the last 6 years and I have installed 8031 8051 and phillips 89c52 with no problem. I am now trying to use an atmel 89c52 and it will not work. This circuit uses an external rom monitor and external ram spce for debugging. but the Atmel will do nothing. I don't even see any activity on the adress/data lines. The device does not have any program flashed internally. I had a phillips 89c52 in the circuit and working then repaced it with the atmel and nothing put the phillips back in and it works fine. both devices are 24Mhz and both are new samples from the manufacturer.
Any ideas would be appreciated.
Thanks in Advance
Jim