Stable ADC readings

[dream-]

Well if I understood what the problem was I would not be asking here

The fact is that the ADCIN code gives me an oscillating reading, and the manual method gives me a stable value.

I don't know the reason, but I would like to know. This is a 16F688.

[mackrackit]

For what it is worth I agree with Steve.
I tried ADCIN a couple of times and did not like it. Others swear by it though. ..

Keep doing it the way you are.

[mister_e]

I would love to see the whole code with ADCIN. Sometime if you play with some ADC registers, and you place them Before or After the DEFINEs, it may end-up with unexpected results.

[Acetronics2]

Hi,

Found in the Datasheet ...

Note:

The GO/DONE bit should not be set in the
same instruction that turns on the ADC.
Refer to Section 8.2.5 “A/D Conversion

Procedure”.

a beginning of an explanation ???

Alain

[Bruce]

ADCIN doesn't work with port pin aliases. Use ADCIN 2,W0, or define PinProbe as a constant. PinProbe CON 2 would work.

Also ADCIN doesn't setup TRIS, ANSEL or ADCON1. So you end up with Fosc/2 for your A/D clock because ADCON1 defaults to all 0's. So you're way out of spec for a 4MHz osc. Fosc/8 would be a good one to use with 4MHz (see datasheet).

[Acetronics2]

Bruce ... 1K points ...

as always !!!...

Shame on me.

Alain

[mister_e]

Blonde moment here too

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