Hi,
look at my comment in the program text.
I hope this helps.
Imre


On Mon, 7 Jun 1999, Andreas Magnusson wrote:

> Hello!
>
> I have a problem.... I have programmed a "test program" for a robot I have
> built (PIC16F84 used). The program controlls a stepmotorcard. Everything
> seems to work exept one thing RB3 pin is allways high... The pin should
> pulse like the other ones. I have checed the circuitboard and also tested
> with two different MCU:s. I programmed a small program to only clear portb
> it worked. I cant really understund why the pin allways is high....
>
>
> /Andreas Magnusson
>
>
> LIST P=16F84
>  INCLUDE "P16C84.INC"
> ;*************************
> RAM ORG 0x0C
> CNT RES 1
> CN1 RES 1
> CN2 RES 1
> TEMP RES 1
> M3 RES 1
>
> ORG 0
>  GOTO START
> ORG 0X30
> ;*************************
> START
>  BSF STATUS,RP0
>  CLRF TRISA
>  CLRF TRISB
>
>  BCF STATUS,RP0
>  CLRF PORTA
>  CLRF PORTB
>
>
> M3A
>          CLRF PORTA
>          BSF PORTB,6
>          BCF PORTB,7
>          CALL KORTM3                    ;porta works as a adressbuss and
> select Motorcard 3
>          CLRF M3
> M3TABLE
>          MOVF M3,W
>          CALL FTABLE
>          MOVWF PORTB
>          NOP
>          BCF PORTB,6                        ;clocking in the value from
> ftable into a data latch on the stepmotorcard
>          NOP
>          BSF PORTB,6
>          MOVLW .130
>          CALL DELAY
>          INCF M3
>          MOVLW .7
>          XORWF M3

!!! If you want to compare M3 with 7 here, the please do not forget:
        XORWF M3, W

        otherwise M3 contains BULLSHIT !!!

>          BTFSC STATUS,Z
>          CLRF M3
>          GOTO M3TABLE
>
> ;*****************************
> FTABLE ADDWF PCL
>  RETLW B'01001111'
>  RETLW B'01001001'
>  RETLW B'01110001'
>  RETLW B'01000001'
>  RETLW B'01000110'
>  RETLW B'01000000'
>  RETLW B'01111000'
>  RETLW B'01001100'
>
> ;*****************************
> KORTM3 BSF STATUS,RP0
>  CLRF TRISA
>  CLRF TRISB
>
>  BCF STATUS,RP0
>  MOVLW 06h
>  MOVWF PORTA
>  RETURN
>
> ;*****************************
> DELAY MOVWF   CN2
> LOOP    MOVWF   CN1
> AGAIN   NOP
>  NOP
>  NOP
>  NOP
>  DECFSZ  CN1,F
>  GOTO    AGAIN
>  DECFSZ  CN2,F
>  GOTO    LOOP
>  RETURN
> ;********************************************************
> end
>
>