On Mon, 27 Nov 1995, Mike Barrett wrote:

>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.

This is sample code: " how to sleep and wake-up with portB"

Port B is able to wake up from sleep mode on a change state on its pin:
 PB4, PB.5, PB.6 or PB.7,


There is to way to get out from sleep mode:
    - by an interrupt routine (GIE=3D1)
    - by an event (GIE=3D0)

1=B0/ Just configure PB4..PB7 as input for example:=20
        PB4 and PB.7, PB.5 and PB.6 are output

2=B0/ Make a read of port B to latch value,

3=B0/ Set RBIF bit to enable interrupt on portB change

4=B0/ go in sleep mode


--------------------------------
*** A/ Wake-up with interrupt

; before, be sure RBIF is not active, RBIE is not set, bank 0 is activated
; don't forget RBPU bit to set pull-up on or off (depend your hardware)

       org 0            ; RESET VECTOR
       goto start

       org 4            ; INTERRUPT VECTOR
       bcf INTCON,RBIE
       movf PORTB,W
       bcf INTCON,RBIF
       retfie


start: bsf   STATUS,RP0 ; STATUS address =3D 03h (or 83h), RP0 =3D STATUS.5
                        ; SWITCH to bank 1 (register 80h to FFh)
       movlw 090h       ; PB7 PB6 PB5 PB4 PB3 PB2 PB1 PB0
                        ;  in  out out in out out out out
       movwf TRISB      ; TRISB address =3D 86h

       bcf   STATUS,RP0 ; STATUS address =3D 03h (or 83h), RP0 =3D STATUS.5
                        ; SWITCH to bank 0 (register 00h to 7Fh)

       movf  PORTB,W    ; Read PORTB (PortB address =3D 03h)

       movlw 088h       ; GIE =3D 1 and RBIE =3D 1
       movwf INTCON     ; INTCON address =3D 0Bh

       sleep            ; ENTER SLEEP MODE, low power, no oscillator =20
       nop              ; after sleep instruction, at the wake up the next
instruction is executed before jumping to the INT vector

;   .... program will continue after wake-up and interrupt
       goto start

--------------------------------
*** B/ Wake-up without interrupt

; Another way is to skeep interrupt routine and use only PORTB wakeup
       org 0            ; RESET VECTOR
       goto start


start: bsf   STATUS,RP0 ; STATUS address =3D 03h (or 83h), RP0 =3D STATUS.5
                        ; SWITCH to bank 1 (register 80h to FFh)
       movlw 090h       ; PB7 PB6 PB5 PB4 PB3 PB2 PB1 PB0
                        ;  in  out out in out out out out
       movwf TRISB      ; TRISB address =3D 86h

       bcf   STATUS,RP0 ; STATUS address =3D 03h (or 83h), RP0 =3D STATUS.5
                        ; SWITCH to bank 0 (register 00h to 7Fh)

       movf  PORTB,W    ; Read PORTB (PortB address =3D 03h)

       movlw 008h       ; GIE =3D 0 and RBIE =3D 1, NO INTERRUPT
       movwf INTCON     ; INTCON address =3D 0Bh

       sleep            ; ENTER SLEEP MODE, low power, no oscillator =20
       nop              ; after sleep instruction, at the wake up
                        ; no interrupt is fetched due to GIE=3D0

       bcf INTCON,RBIE  ; clear no match  condition
       movf PORTB,W
       bcf INTCON,RBIF


;   .... program will continue after wake-up=20
       goto start



Regards,  =20
             Philippe.