> It thus appears that the PIC16F876A is having trouble acting as an I2C > slave. I have tried multiple PIC16F876A chips, but all have the same > problem. I am hoping someone here may know what the problem is before I > start doing some serious debugging work. Are there any known I2C > problems with the PIC16F876A chips? I did check the Microchip website > and found no meantion of any problems. I have also consulted the > PIC16F876 to PIC16F876A guide. Has anyone had a similar experience? I don't know about the A version of these chips, but the older versions have the nasty habit of sampling the ACK bit on the wrong edges of SCK in master mode. This causes a race condition with a few pF or nS one way or the other making a difference in whether the master sees the ACK or not. I had a case where it worked with a scope probe attached but not without. There are also other gotchas in the MSSP implementation that Microchip seems reluctant to admit to. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads