Hi Marc,

perhaps you could try this..


> Marc D. Spencer wrote:
>
> > What am I doing wrong? this should be the simplest start...turn all port b
> > pins on.
> >
> > Code:
> >
> > 0000    MOVLW   00
> >         MOVWF   0A

No need to clear the PCLATH register because it automatically resets to
0 on reset.

> >         GOTO    005
> >         NOP
> >         NOP

If you are not using interrupts, you can keep writing code in these
locations.

> > 0005    CLRF    04
> >         CLRF    03

Don't know why you are clearing the FSR and status registers ???
However, there is no need to do this.

Status resets to a known value, the main thing to note is the RP0 bit
which is set to RAM Page 0.
The value in FSR does not matter because you are not using it.

> >         MOVLW   07
> >         MOVWF   1F

This needs to be done to disconnect the comparators from porta inputs.

> > 0009    BSF     03,5
> >         CLRF    06
> >         MOVLW   FF
> >         BCF     03,5
> >         MOVWF   06
> >         GOTO    009

You do not need to go back to '0009' because you code has already done
what you wanted it to do. You can just sit in a closed loop afterwards.


> > Using a 16C622, wired trivially:
> >
> > pin 4 1K to Vcc, .1uF to Gnd

You can use the POR reset to eliminate the external .1uF cap if you
like. That means that you can also hard wire the MCLR pin to 5V to save
a resistor.
To enable the POR timer, the PWRTE bit should be set to 1.
Your programmer should have a visible selector for this.
Also, make sure the WDT is disabled.

> > pin 5 gnd

ok

> > pin 14 to TTL clock module, 10MHz

Your clock input should be pin 16 (Osc1) not pin 14.

> > pin 12 to +5

Pin 14 is Vdd and should be at +5V. Pin 12 is portb pin RB6.

> >
> > looking at pins 6-13...all have about .25 v on them, but won't sink an LED
> > (with 1K res).

Probably confusing to you, but your chip is not set up properly.

> > Help?

Try this code.

Title "Activate Port B"
;
list p=16c622,                  ; processor type
;
status  equ 3h                  ; these definitions help you understand
rp0 equ 5h                      ; your code a little easier
porta   equ 5h
portb   equ 6h
trisa   equ 85h
trisb   equ 86h
CmCon   equ 1fh
;
; -------------
; PROGRAM START
; -------------
;
        org 000h

        movlw 7h                ; set comparator inputs as digital
        movwf CmCon

        bsf status,rp0          ; Ram Page 1 to access tris registers
        clrf trisa              ; porta = all outputs (stops floating inputs)
        clrf trisb              ; portb = all outputs
        bcf status,rp0          ; back to Ram Page 0

        movlw 0xff
        movwf portb             ; set all PortB pins = 5 Volt

here    goto here               ; finished, stay here forever

        end

> > (I don't have a scope, but im pretty sure the power is clean - 7805 with
> > appropriate filtering off a wall wart)

Good idea for a beginner to have a fixed 5V supply. It's very easy to
connect the wrong voltage with a 'Lab' type supply.

--
Best regards

Tony

Multimedia 16F84 Beginners PIC Tools.
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