>Has anyone got any simple code that I can 'borrow' to make a '84 wake up
>from sleep mode when an input changes state? I also want some code to put
>the device back into sleep mode.

        ORG     H'000'          ;Reset vector for 16C84 PIC's
        btfsc   STATUS,_PD      ;
        goto    Star1
        goto    Star2

        ORG     H'004'          ;Interrupt vector
        goto    ISR

        ORG     H'005'
Star1   btfsc   STATUS,_TO
        goto    PwrUp           ;Power-up condition, TO & PD = 1
        goto    X_Init          ;WDT time-out, not sleep T0=0, PD=1
Star2   btfss   STATUS,_TO
        goto    Wake_up         ;WDT time-out, sleep T0=0, PD=0

Wake_up sleep

Check page 2-543 of the 94 databook for explanation of the TO and PD Status
bits., and the "SLEEP" instruction. PortB and INT interrupts will wakeup the
processor as well as a watch-dog timer time-out. Execution may start at the
ISR vector H'004' or elsewhere, depending on how the interrupts are configured.