Hi Rona,

What I got from your post is that you were using 1.8MHz crystal on P89C51 and when you changed the chip, it gave you mere 1 Hz.

As far as clock frequency is concerned, I have observed that even if there is no software in a micro, it should produce correct clock.

Please check again that your crystal is connected to pin 20 & 21 (for PLCC package) or pin 14 & 15 (for LQFP) and also remember to add capacitors as advised in the datasheet of P89C664.

First the clock should be OK, then you might suspect the conversion you have done, if the software does not work.

Best of luck.

IA