Hi Anbar,

Your problem is that your "__CONFIG" statement does not have "_LVP_OFF" as
one of your parameters.  This screwed me up too when I found out that it was
required in PIC16F87x parts.

The statement should be:

 __CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_OFF & _XT_OSC &
_WRT_ENABLE_OFF & _LVP_OFF

myke

----- Original Message -----
From: <anbarsystem@ZAZ.COM.BR>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, February 07, 2000 11:00 AM
Subject: First Project with PIC16F87x doesn't work


> Hi All,
> My first project with the PIC16F87X doesn't work. I am simply trying to do
a
> conversion A/D in the PORTA0 and show it  in PORTB with leds.Also a led
> blinking in the PORTC6 using TMRO overflow. I'm using a 4MHZ cristal.
>
> See my Codes below.
>
> #DEFINE LED     PORTC6
>
>         list p=16f873
>
>         include "p16f873.inc"
>
>
>          __CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_OFF & _XT_OSC &
> _WRT_ENABLE_OFF
>
> ;----------------------------------------------------
> ; Start at the reset vector
>         org 0x000
>
>
> Start:
>         clrf PORTA
>         clrf PORTB
>         clrf PORTC
>         bsf STATUS,RP0
>         movlw B'00000111'     ;TMR0 prescaler, 1:256
>         movwf OPTION_REG
>         movlw b'00000001'     ;PA0=IN
>         movwf TRISA
>         movlw b'00000000'
>         movwf TRISB                 ;PB=OUT
>         movlw b'00000000'       ;PC=OUT
>         movwf TRISC
>         movlw b'00001110'     ;VREF+ VDD E VREF- VSS, PORTA0  A/D IN
>         movwf ADCON1
>         bcf STATUS,RP0      ;Fosc/8, A/D ON
>         movlw b'01000001'
>         movwf ADCON0
>
>
>
> MAIN:
>         clrf TMR0
>         btfss INTCON,T0IF     ;Wait for Timer0 to timeout
>         goto $-1
>         bcf INTCON,T0IF
>         btfss LED
>         goto LED_ON
>         bcf LED
>         goto SET_AD
>
> LED_ON:
>         bsf LED
>
> SET_AD:
>         bsf ADCON0,GO     ;Start A/D conversion
>
> Wait:
>         btfss PIR1,ADIF     ;Wait for conversion to complete
>         goto $-1
>
>         movf ADRESH,W     ;Write A/D result to PORTB
>         movwf PORTB
>         goto MAIN
>
> I would appreciate it if someone could make a suggestion.
>
> Thanks in advanced.
> Anbar.
>