PIC18F2553 ADC and VREF

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alanwms
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PIC18F2553 ADC and VREF

Postby alanwms » Sat Mar 30, 2019 7:30 pm

Hello Ben. I have the zipped patches in my FC7 file but still having an issue specifically with analog3 on the pic18f2553. I have a temp sensor connected to AN3, and I have a voltage emanating from the pin. The voltage should be .7v and it is actually around 3.5v

I'm not sure but it looks to me like the Vref pin is switched on and I have settings indicating it should be off. I have tried a few tricks but have not succeeded in getting rid of this voltage.

I have a jpeg of the details attachedm- Can you confirm that the FC7 is handling the vref stuff correctly for me?
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Analog Issue 1.jpg
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Re: PIC18F2553 ADC and VREF

Postby Benj » Tue Apr 16, 2019 11:56 am

Hello Alan,

I've moved your post into a new topic.

Have you tried changing the conversion speed? 24MHz is probably a bit on the fast side. Might be worth trying to increase the acquisition time property too?

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Re: PIC18F2553 ADC and VREF

Postby alanwms » Mon May 13, 2019 4:24 pm

Hmmm - The chip is running internal 8mhz oscillator. But good thoughts regarding acq time and speed.