I'd like to thank each of you that responded to my I2C question. After reading the additional application notes suggested by Leo and replacing my I2C routines that used the integrated I2C functions of the 87LPC764, I still had no success.

Then I thought of something that I should have thought of earlier: perhaps it was the hardware?

It was... A continuity check quickly showed a short between SDA and SCL. Duh. I tracked down the problem, fixed it, and as soon as the short was resolved I was able to talk to the RTC part on the first try using Peter's I2C code--which I think I'll stick with. Peter's code is much tighter than the code that uses the 87LPC764's integrated I2C features and, as Peter mentioned, it works on any 8052. This was also a plus since I am now testing my code on an SBC (non-87LPC764) to which I can download my code via serial rather than having to burn (and throw out) an 87LPC764 for each iteration.

Thanks again for all your help.

Craig Steiner