What is this: Unhandled exception in interrupt handler TypeError: 'str' object is not callable

  • It occures when an interrupt is triggered after a Timer.Alarm invoked for the first time.
    The code running inside the ISR handler is something like P += 1.

    Any help is appreciated.

  • No, the callback handler can be inside a class. But then the handler must have self as first additional argument. Example (ESP8266 one, but principle should work) with ISR fucntion sample.

    class acquire:
        def __init__(self):
            self.adc_read = machine.ADC(0).read
            self.data = array.array("L", [0] * _BUFFERSIZE)
            self.index_put = 0
        def sample(self, x):
            self.data[self.index_put] = self.adc_read()
            self.index_put = (self.index_put + 1) % _BUFFERSIZE
            self.irq_busy = False

  • @robert-hh Maybe I found the problem. I was initializing the callback handler for the Pin inside a class. The call back method was a class method. I realized that callback handlers must be single functions.

  • Do you have more insight to your code, especially the statement where yoe set up the timer alarm and the interrupt handler itself?

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