Adam,
I haven't gone through your code but check your ADCON1
settings.  Use the chip datasheet as a reference and NOT the
Microchip Mid-range Reference manual.  The A/D bits for
selecting right/left justification are wrong in that doccument.

Cheers,
Andrew


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---- On    , Adam Cooper (adam@PULSARINFORMATICS.COM) wrote:

> Hi,
>
> When I do an A/D conversion I get funny results.  If I use
right
> justified,
> ADFM = 1 and try and read 5V... I get something like (011-
1000111).
> However as soon as I switch to left justified, ADFM = 0,  I
get all 1's
> (16
> of them)... including the extra 6 bits that should be set to
0..
> (11111111-11111111) - should be (1111111-111000000)
>
> Any Ideas / Help?
>
>
> bsf          STATUS, RP0     ; Select bank 1
> movlw     0x0FF                  ; RA5-0 inputs,
> movwf     TRISA
> movlw     0x02                   ; set all of port E
> movwf     ADCON1           ; to Digital I/O, port A to analog
> clrf          STATUS               ; select bank 0
> movlw       B'11000001'       ;RC osc [7-6], A/D ch0 [5-3],
a/d on [0]
>  movwf       ADCON0
>                                         ; need to wait the
proper
> acquisition time ~20us
>                                         ;  20us = overhead +
(loop time
> *
> loop count)
>                                         ;  20us = 2us  + (3us
* loop
> count)
>                                          ;   loop count = 6
>
> ADStart:
> movlw     0x06                              ; 1 us
> movwf     DELAY                         ; 1 us
>
> ADConv_Acquisition:                    ; ----loop-----
> decfsz     DELAY, f                          ; 1 us   -
> goto       ADConv_Acquisition          ; 2 us   -
>                                                     ; ----
loop-----
>
>
> banksel  ADCON0                       ; additional 2 us...
padding
> bsf         ADCON0, GO
>
>
> btfss     ADCON0, GO
> goto     ADReady
> goto    $-2
>
>
> ADReady... just displays the value and goto's ADStart
>
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