How to setup GPIO Level interrupts correctly

[u9357]

If i setup GPIO level interrupt as follows,

ret = gpio_pin_interrupt_configure_dt(&spiInterrupt, GPIO_INT_TRIG_LOW |GPIO_INT_MODE_LEVEL);

My gpio interrupt callback keeps on getting executed. My ISR only releases a semaphore, the SPI read operation is in main thread.
Until i read, the peripheral will keep the GPIO pin active. If i setup the pin as follows

ret = gpio_pin_interrupt_configure_dt(&spiInterrupt, GPIO_INT_TRIG_LOW);

then everything works correctly, I get only one interrupt call. But this call is wrong (or is it?) and if compiled with CONFIG_ASSERT
it will fail with assertion "Must either enable or disable interrupts"

Whats the right way to setup GPIO interrupts for my case where an interrupt should release a semaphore and the main thread can then
read from SPI.I cannot use edge triggers because of Errata 153.

[Håkon Alseth]

Hi,

 

The function requires that you either enable or disable interrupt via the GPIO_INT_* flag.

If you are using an external pin that is active low, you can pass the flag "GPIO_INT_LEVEL_INACTIVE"

 

Do you have a pull resistor on this line?

You can configure that like this:

ret = gpio_pin_configure_dt(&spiInterrupt, GPIO_INPUT | GPIO_PULL_UP);

 

Kind regards,

Håkon

[u9357]

Im trying to enable interrupts here with "GPIO_INT_TRIG_LOW | GPIO_INT_MODE_LEVEL". But the ISR keeps getting executed as long as the PIN is low. For the PIN to rise back up, i need to make a SPI read operation with the peripheral that the pin is connected to. The code for the read operation is in main() which never gets executed.

[u9357]

Håkon Alseth said:

Do you have a pull resistor on this line?

The gpio pin is being actively driven by the SPI peripheral, a pull up won't help here.