Question on debug reporting re A/D in a 18f2450

[Tim_B]

Hi Isis team
I'm trying to sim my code in a 18f2450 and starting on the A/D conversions

I'm running this code

Code: Select all

    Device 18f2450
    XTAL 16
    Dim VAR1 As Word 

    ADCON0 = 0                                                  ; AD channel 0 is used
    ADCON1 = %00001110                                    ; Only Channel 0 is used and VRef- = VSS Vref+ = VDD
    ADCON2 = %10000011                                    ; FOSC/2, 6 TAD, Right justified
    ADCON0.0 = 1                                               ; Turn on the AD unit
 
While 1 = 1
    ADCON0.1 = 1                                                ; Start the conversion
    While ADCON0.1 = 1:Wend                             ; Wait until its stopped
    VAR1.BYTE0 = ADRESL                                   ; Read the data
    VAR1.BYTE1 = ADRESH
    DelayMS 200
Wend 

And I'm getting this debug error
Voltage references for ADC conversion yeald a 0V range (V+ = 0, V- = 0)

Does this mean that you have not implemented the A/D converter in this model or are you trying to say the config bits are set wrong? I have treble checked the Mchip data sheet and I'm sure its right.

BTW it's not returning the right result
Thanks

Tim

[Roshan]

set adcon1.7 before ad conversion & see result

[Tim_B]

ADCON1.7 is an unimplemented bit, if you thinking about right justification its on ADCON2.7

Besides my concern is with the A/D error messages unless you turn them off the sim grinds to a halt and that it produces 0 even if you tie it to 5v

[Ettore]

I'm looking at this. I'll contact you ASAP.