Timeline for Arduino fast ADC sampling--which burst control is best?
Current License: CC BY-SA 4.0
10 events
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| Jan 15, 2022 at 0:07 | history | edited | Dave X | CC BY-SA 4.0 |
Switch code to Timer-controlled pulse and achieve 6.5us sampling.
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| Jan 11, 2022 at 15:44 | comment | added | Dave X |
... The pulse length control is sloppy because the pulse is started out of sync with the sampling, and finishes in sync with the sampling. I like the end synchronization with the samples for my particular application, but it would be nicer to configure a timer as a one-shot and trigger it in the ISR when the sample == 0, then you could get higher resolution pulse lengths with both the start and end of the pulse synced with the sampling. Maybe it could reach 6.5us/sample with 8-9 bit resolution.
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| Jan 11, 2022 at 15:36 | history | edited | Dave X | CC BY-SA 4.0 |
Edit logic based on EdgarBonet's suggestion.
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| Jan 11, 2022 at 15:30 | comment | added | Dave X |
@EdgarBonet -- With the ADIF=1 trick, ADCSRA |= bit(ADIF) | bit(ADIE) would clear any pending interrupt and enable future interrupts. Sounds good. I could then use the ADCSRA & bit(ADIE) instead of burst as my "sampling" state variable and save a test. I've been tweaking things to get down to the 13us/sample threshold that I can get for the ADPS2:0=0b100 /16 1MKz speed that has full 10bit accuracy, but I haven't trimmed the ISR down enough for the /8 clock. I like the pulse control in the ISR for the sync in my use case, but it's sloppy. Maybe pulse on sample vs micros() state var?
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| Jan 10, 2022 at 19:39 | comment | added | Edgar Bonet |
Re "I left free-running automatic ADC enabled and switched the data recording on and off.": I think you could do that by toggling just ADIE, without touching ADSC. Maybe clear the interrupt flag when setting ADIE, to avoid getting an interrupt from the last conversion of the previous burst.
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| Jan 9, 2022 at 21:33 | history | edited | Dave X | CC BY-SA 4.0 |
Update code
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| Jan 7, 2022 at 14:01 | vote | accept | Dave X | ||
| Dec 8, 2021 at 3:56 | history | edited | Dave X | CC BY-SA 4.0 |
added 270 characters in body
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| Dec 8, 2021 at 3:50 | history | edited | Dave X | CC BY-SA 4.0 |
added 270 characters in body
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| Dec 8, 2021 at 3:23 | history | answered | Dave X | CC BY-SA 4.0 |