little more info. Took a picdem2 board, wired to the other master board (removed the PIC) and was able to talk to the I2C devices on it..confirming the wiring is correct. Put the master back in the original board, and proceeded to put the picdem PIC from master to slave. As soon as I load the CON1 register....it starts to hold the I2C lines ;initialize MSSP module bsf TRISC,3 bsf TRISC,4 movlw 0x80 ; initialize slave address movwf SSPADD ; and load to the address register bsf SSPSTAT,SMP ----------------------------------------> breaks here movlw b'00100110' movwf SSPCON1 Is there something fundamentally wrong that Im doing in setting the PIC as a slave? --------------------------------- Cheap Talk? Check out Yahoo! Messenger's low PC-to-Phone call rates. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist