cpu/sam0_common/periph_adc: add work around for errata 2.1.6 #20994
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maribu
added
Type: bug
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Platform: ARM
dylad
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Nov 14, 2024
cpu/sam0_common/periph/adc.c
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| ztimer_sleep(ZTIMER_USEC, 1); | ||
| # else | ||
| /* let's rather be safe than sorry */ | ||
| busy_wait_us(100); |
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Any reason to wait 100 us here but 40 us with ztimer_usec ?
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The busy_wait_us() is just counting CPU cycles and not that precise. I make the comment above a bit more specific.
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I also reduced it two twice the specified amount. That turns out to work reliably on my "bad MCU" affected by the bug and there should be enough safety margin.
This adds a delay between enabling the ADC and starting to sample on the SAMD5x MCUs when the internal bandgap reference is used. Co-authored-by: Dylan Laduranty <[email protected]>
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dylad
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Nov 17, 2024
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Thx :) |
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Contribution description
This adds a delay between enabling the ADC and starting to sample on the SAMD5x MCUs when the internal bandgap reference is used.
Testing procedure
Before,
adc_sample()on one of the SAMD5x MCUs I have at hands got stuck when the internal bandgap reference was used by never leaving this loop:Now, it works also on the "special" MCU that got stuck before:
Issues/PRs references
None