fix esp32 timer resolution #63
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v2.3.0 Release merge from develop branch
Set the timer frequency to 1MHz to match expected microsecond resolution for the alarm value.
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Hi @sneakyaardvark , Good catch! thank you for reporting back and pull back. It is strange that the API makes timerBegin uses frequency but timeAlarm uses micro seconds. But to keep api compatibility we must convert init_clock to frequency instead of hardcode the value. Can you please add this change to the code? // convert micro seconds to frequency
uint32_t frequency_hz = 1000000 / period_us |
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Set the timer frequency to 1MHz to match expected microsecond resolution for the alarm value.
The issue: the ESP32 library timerBegin(frequency) function uses a frequency in Hz to set the resolution of the timer and the alarm value (in timerAlarm()). Currently both the frequency and alarm value are set to the BPM in microseconds, so the interrupt will always be every second (or a ratio, if the tempo is later changed, changing the alarm value but keeping the default resolution).
Solution: set the timer frequency to 1MHz to match the expectation the alarm value is in microseconds.