cpu/sam0_common: adc: implement 16 bit mode by oversampling #19165
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dylad
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Overall changes looks good to me.
But using tests/periph_adc with RES set to ADC_RES_16BIT doesn't work as expected.
Works fine as long as the ADC line is below VCC_REF / 2 but it returns an error when we're above VCC_REF / 2.
I guess this is because this variable is set as int16_t
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Good catch! |
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Works as expected now ! |
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Contribution description
The precision of measurements can be increased by taking multiple measurements.
For this, the ADC implements an summation/averaging mode in hardware.
The best way I found to expose this in our ADC API is via the 16 bit resolution mode.
We can take up to 16 samples without exceeding the internal ADC register (after which 'automatic right shifts' happen - the result gets truncated).
Testing procedure
Issues/PRs references