Help with ADC code

[nigelb]

Hi....could someone please just tell me if the following code is ok....it seems very simple to me and so I don't trust that I'm going about this the right way!

The declares are in the section above the start section, where dims and symbols are etc. The sampling code is obviously in its own section within the main code.

I have set up the adc port and ADCON0/1 registers ok so I'm not worried about them.

sample1/2/3 are byte, adcvalue is a float.

I am assuming (hoping) that the ADIN command takes care of the MSB/LSB malarky and Bob's your uncle....help! lol

DECLARE ADIN_RES 10     ;Using 10bit ADC
DECLARE ADIN_STIME 50   ;Allow 50us sample time

;Get first sample and store
    sample1 = ADIN 0       ;Place the conversion into variable
    DELAYUS 1

;Get second sample
   sample2 = ADIN 0
    DELAYUS 1
    
;Get third sample
    sample3 = ADIN 0
    DELAYUS 1

;Calculate average
   adcvalue = sample1 + sample2 + sample3

Many thanks in advance

Nigel

[dmTulsa]

I think Sample 1/2/3 should be words since your reading in 10 bits. I believe that its right justified by default. I didn't run the sample but it looks ok if you change Sample to a word.

I did a write up about ADC readings http://www.picbasic.org/forum/showthread.php?t=12798 This is a much better way than averaging

Doug

[nigelb]

Code should read additionally as follows for all 3 samples and final calc

Sorry to be so messy, but the edit option for the firt post has disappeared !

;Get first sample and store
    GO_DONE = 1              ;Start conversion
    WHILE GO_DONE = 1 : WEND  ;' Poll the GO_DONE flag for completion
    sample1 = ADIN 0       ;Place the conversion into variable
    DELAYUS 1


;Calculate average
   adcvalue = (sample1 + sample2 + sample3) / 3

Thanks again

Nigel

[nigelb]

Dear all......it's tough being an idiot

After trying all manner of code variations to get something out of the ADC and onto my 7seg display I finally discovered the problem........

While working on a bit of my program I had switched 'off' the anode transistors in a section of the code then, when writing in the ADC code with a jump to another section to flash the segments at a certain ADC value (for test purposes), I had missed the point that the anodes where not powered up......GOOD GRIEF.....

Powered up the anodes and bingo....result !!

It's always the simple things that get you.....grrrrrr !!

Nigel