J. Ian LindsayThe OSHPark projects for this breakout were just updated, as was the source repository.
Note about the input filtering
This board is based on Microchip's reference schematic, complete with RC low-pass filters at each input pin. This filters everything above about 16kHz.
Note about part change
Microchip released a new version of the MCP356x last year. All documentation has been updated, and both the Arduino demo driver, and the non-blocking driver written around CppPotpourri have been updated to work with both versions of the part.
The new version has support for an internal Vref of 2.4V (which also outputs on the REF+ pin. To make matters worse, that internal reference is enabled out of reset. So the driver was extended in such a way as to achieve the old part's behavior (external Vref) unless the flag is passed to use the internal Vref. Why did you select a rail-to-rail ADC to throw away 33% of the range? Oh well....
Discussions
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You can still use the rail-to-rail range. It just isn't the default out of reset.
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OOF... I was just looking at possibly integrating a few of these into a project of mine. Now I have to rethink things.
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FWIW, you'll still get the full resolution. Just not the full range. That is: The ADC will carve up the 2.4V range into 24-bit slices when using the internal Vref.
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Agree, seems a shame to waste half of the most significant bit because of this limitation. I wonder what the reason for this limitation is.
Now I need to wrangle with the question of whether I consider a very low noise Vref (i.e. internal Vref) to be more desirable than achieving the full resolution, vs. accepting noise on a Vref signal I provide... better get my head into the datasheet SNR graphs... *sigh*
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