Running two concurrent threads

[jickster]

If you only had enough time to fully finish executing the “compute the beat” code or “flash leds”, I think you would put priority on “compute the beat” because at least you could record that a beat happened.

Is my assumption correct?


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[hdsjulian]

right. but even if i do it that way i can only sample 1000 times per second, right?

[jickster]

right. but even if i do it that way i can only sample 1000 times per second, right?

No.

One thing you have to understand is documentation is terribly incomplete.

The documentation says you can only do interrupts down to 1ms but the uPy source code shows you can do it much faster.

ports/esp32/machine_timer.c

It shows there’s a freq argument that you can use instead of the period argument.

There’s another issue: interrupt jitter.
You’re sampling audio so sampling exactly every X ms is critical.

Unfortunately the implementation of the timer isr does not call the uPy callback in the isr.
Instead, it uses mp_sched_schedule to schedule it to be executed “as soon as possible” which will introduce jitter.

What interface are you using to sample the microphone?



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[hdsjulian]

true. but this won't keep me from only sampling 1000 inputs per second?

[jickster]

true. but this won't keep me from only sampling 1000 inputs per second?

No


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[hdsjulian]

sorry my second comment was useless. don't know how i double posted this

[hdsjulian]

using the ADC interface. it's a max4466 electret microphone