how to write/ add a callback modules?

[synapticonashaikh]

Hello all,
I'm working on a project where I'm porting the Micropython stack on one of the SOC boards. As the support library of Micropython for the SOC (XMOS based) I'm using is not listed, I used the ports/minimal project. Now, module by module, I'm developing the modules that can provide access to the hardware layer. So, now moving further, I want to build a callback module which takes a user function and triggers based on the GPIO interrupt. In short, just like any ARM-based GPIO interrupt.

Therefore, I would like to request you all help me in creating a callback function based on interrupt.

Micopython sample code:

from machine import Pin
def callback(p):
    print('pin change', p)
p0 = Pin(0, Pin.IN)
p0.irq(trigger=Pin.IRQ_FALLING, handler=callback)
while True: 
    pass

[jimmo]

@synapticonashaikh You should look at how the other ports implement exactly this (e.g. for pin IRQs). ports/samd/machine_pin.c is a good example (but just about all ports do this). Let us know if you have any specific questions about how this is done.

[jimmo]

@synapticonashaikh

In val=gpio.pirq(handler=Func, trigger=IRQ_FALLING|IRQ_RISING, hard=False)

you are using the IRQ_FALLING and IRQ_RISING constants directly. You need to write gpio.IRQ_FALLING

[synapticonashaikh]

After replacing the IRQ_FALLING with gpio.IRQ_FALLING, I'm getting the following error. Rest everything is same

Traceback (most recent call last):
  File "<stdin>", in <module>
TypeError: argument num/types mismatch

[jimmo]

You have copied the argument handling code from a function that has a self argument, and so it's offsetting the arguments by one:

mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);

Your method is just directly on the module, not on a class, so it has no self argument. Remove the two - 1 and it should work.

[synapticonashaikh]

I practically tried all the combinations, but the result was the same.
I removed self from the script, and in n_args - 1, pos_args + 1 removed -1, +1. Likewise did all the combinations.
I notice that printf("in the gpiopin_irq function \n\r"); is not executing, which might mean that due to syntactical error, it is not entering the function at all.

[jimmo]

You have STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pin_irq_obj, 1, gpiopin_irq); whcih says this function must take one positional argument. But you're calling it with entirely keyword arguments. Change the 1 to a 0.