ADC readings off on Itsy Bitsy M4

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Bekar_T
 
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Joined: Wed Apr 21, 2021 12:41 am

Re: ADC readings off on Itsy Bitsy M4

Post by Bekar_T »

Nope, actually, cancel that.

2% is an expression of the sum of ADC and DAC errors. ADC alone has a very consistent 5% error when readings are taken in reference with the external source.

I'm assuming I'll find a DAC error to be about 3% and "in an opposite direction", resulting in 2% net error when they are tied with a jumper wire.

If that can't be addressed at least to some extent, I think it should at least mentioned somewhere because when a description says:

Dual 1 MSPS 12 bit true analog DAC
Dual 1 MSPS 12 bit ADC

A beginner like myself (who, as we've established, these boards are targeted at) would not assume there could be an unspoken assumption that 5% error in readings is not an odd thing to happen.

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Bekar_T
 
Posts: 22
Joined: Wed Apr 21, 2021 12:41 am

Re: ADC readings off on Itsy Bitsy M4

Post by Bekar_T »

Wellp, now I'm confused.

DAC output has barely 0.5% error when measured independently.

So main source of error is ADC and it varies A LOT depending on . . . I don't know what.

Does this mean that even if I go through the labors of calibrating and compensating for the error in ADC, it will still need adjusting in every specific circuit configuration?

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