Hi Stewart


It's ok with you example. But I didn't understand why I can't read the Port B
and make a operation like xor with it.

regards


Stewart Pye a ˇcrit :

> Hi Michel
>
> Your problem is portb is configured as an output. You then try to move
> portb to w and xor it with b'01000010'. That's why you get both leds on.
> There is a much simpler way to do this any way. From your first call alum:
>  (this asumes the leds are active high)
>
> repeat
>                 btfsc   porta,0         ;is ra = 0.....
>                 goto    rb6on           ;
> rb1on
>                 clrf            portb           ;yes
>                 bsf             portb,1         ;turn on rb1
>                 goto    repeat
> rb6on
>                 clrf            portb           ;no
>                 bsf             portb,6         ;turn on rb6
>                 goto    repeat
>                 end
>
> This should work, though you would normally debounce the switch by waiting
> 5ms after the test to check that it is still in the same position.
>
> Regards,
>
> Stewart Pye
> At 07:52 7/05/99 +0200, Michel Mermin wrote:
> >Hi
> >
> >I'm a beginners with the pic 16F84 and I've got a problem. With a switch
> >connected to RA0, I'm trying to switch on a led connected to RB1 and
> >switch off another one connected to RB6 for a switch position ans switch
> >Off RB1 and siwtch on rb6 for the other position.
> >
> >The case where RB1 is on and RB6 if off is ok, but the other case the 2
> >leds are on with a voltage of 2v5 instead on 5v.
> >
> >
> > title  "MM1"
> >;
> >;  fait clignoter PB1
> >;
> >  LIST P=16F84
> >  errorlevel 0,-305
> >  INCLUDE "P16F84.inc"
> >
> >;  Registers
> > __CONFIG _CP_OFF & _WDT_OFF & _XT_OSC & _PWRTE_ON
> >
> >;  Mainline of PROG16
> >
> >temp  equ 1
> >
> > org  0
> >Debut
> > clrf PORTB
> > bsf STATUS,RP0
> > movlw b'00000000'
> > movwf TRISB
> > movlw 0xFF
> > movwf TRISA
> > bcf STATUS,RP0
> > call  Alum
> ;********
> >
> >Repeat movf PORTA,w
> > andlw b'00000001'
> > btfss STATUS,Z
> > goto ZNUL
> > call Etein
> > goto  Repeat
> >ZNUL call  Alum
> > goto Repeat
> >
> >Alum    movlw b'00000010'
> > movwf PORTB
> > return
> >
> >Etein movf PORTB,w
> > xorlw b'01000010'
> > movwf PORTB
> > return
> > end
> >