Hi,

Thanks very much! Your help is much appreciated. I've got everything working
now and I was trying to see what i could do in asm so here's the new code
below that does the same thing, but i think is a bit neater.

-Peter


Code--------

;Setup
 list P=16F877
 include "c:\P16F877.inc"
 errorlevel -302
 __CONFIG _CP_OFF & _HS_OSC & _WDT_OFF & _PWRTE_OFF & _BODEN_OFF & _LVP_OFF
;Declarations
 Cblock 20h
CounterA
CounterB
CounterC
LEDPos
 Endc
 org 0
 goto  Start

Bank1 Macro   ;bank switching macros
 bsf STATUS,RP0
 bcf STATUS,RP1
 bcf STATUS,IRP
 Endm

Bank0 Macro
 bcf STATUS,RP0
 bcf STATUS,RP1
 bcf STATUS,IRP
 Endm

Init Bank1
 movlw b'11110000' ;0,1,2,3 of porta are output
 movwf TRISA
 Bank0 ;bank 0
 movlw b'00000000' ;all porta low
 movwf PORTA
 movlw b'00000001'
 movwf LEDPos
 return


;PIC Time Delay = 1.0000006 s with Osc = 20.000000 MHz
Delay movlw D'26'
 movwf CounterC
 movlw D'119'
 movwf CounterB
 movlw D'85'
 movwf CounterA
 goto Delay_0

Delay_0 decfsz CounterA,1
 goto Delay_0
 decfsz CounterB,1
 goto Delay_0
 decfsz CounterC,1
 goto Delay_0
 return

ShowLED movf LEDPos,0 ;outputs f
 movwf PORTA
 call Delay
 movlw b'00000000'
 btfsc LEDPos,3 ;checks if at 00001000 and
 bsf STATUS,0 ;changes carry bit, etc
 btfsc LEDPos,3
 movwf LEDPos
 rlf LEDPos,1 ;shifts LEDPos left so i can ouput correct sequence
 goto ShowLED

Start call Init

Main call ShowLED
 goto Main
 End


----- Original Message -----
From: "Jinx" <joecolquitt@CLEAR.NET.NZ>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Friday, November 29, 2002 9:23 PM
Subject: Re: [PIC]: First ASM problems


> > work correctly but it look weird, so would it be better to leave 1
> > as high, and connect to LEDs to ground? If i don't change
> > anything it works, but instead of turning LEDs on, the default is
> > all 4 on, and turns 1 off in
>
> Doesn't really make a lot of difference. The PIC pins can sink or
> source about the same current. You might find it easier to work
> with non-inverted logic, ie BSF for on, BCF for off, in which case
> the LEDs can go to ground and you drive them
>
> TRIS registers set ports as inputs after reset. I should think an
> LED may be enough of a pull-down that you may not see a very
> brief flash before you explicitly set TRIS, although I've never
> actually looked
>
> --
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