Trying to define 2 interrupt handlers for the same pin, one for up one for down

RE: Trying to define 2 interrupt handlers for the same pin, one for up one for down

mtsunstrum — Wed, 27 May 2020 21:11:58 GMT

I am not so sure nrfx_gpiote is doing exactly what we think it should be doing ...

I am working thru some issues now ... so not 100% sure on all of this.

But here is my findings: SDK 16.0.0

For @ziv123 question, possibly one might expect you can code it as follows:

// Set up to use more accurate PIN events, not PORT events ...
// Detect both rising/falling edges ...
nrfx_gpiote_in_config_t signal_intr_config = NRFX_GPIOTE_CONFIG_IN_SENSE_TOGGLE(true);

// Set up Pin 22 as a GPIOTE input, with interrupt handler ...
// ... understand we cannot have separate isr for rising / falling edge ... OK
err_code = nrfx_gpiote_in_init(22, &signal_intr_config, isr_my_input_signal_handler);
APP_ERROR_CHECK(err_code);

// Set Pin 22 to generate event when it goes from Lo to Hi level
nrf_gpiote_event_configure(0, 22, NRF_GPIOTE_POLARITY_LOTOHI);

// Set Pin 22 to generate event when it goes from Hi to Lo level
nrf_gpiote_event_configure(1, 22, NRF_GPIOTE_POLARITY_HITOLO);

// Enable GPIOTE Pin 22 to generate event(s), enable interrupts.
nrfx_gpiote_in_event_enable(22, true);

Answering his question, we cannot have seperate ISRs ... but other issues seem unexpected:

With above code, I appear to see following concerns:

GPIOTE seems to be configured in PORT events, not PIN events (high accuracy)
Event 1 for NRF_GPIOTE_POLARITY_HITOLO is not enabled ... ie. not set into Event mode
Seems we cannot have 2 events configured for same pin time
Appears to be a limitation of code implemented in nrfx_gpiote_in_event_enable()
On call into isr_my_input_signal_handler(), 'action' parameter appears to only return 'action' value of toggle
... does NOT appear to return the actual hi/lo or lo/hi transition.
Would not want to read the GPIO pin, because pin state could be lost by that time.

Trying to work around these issues right now ... not sure if others are seeing the same.

RE: Trying to define 2 interrupt handlers for the same pin, one for up one for down

Dmitry — Tue, 19 May 2020 13:32:33 GMT

Hi,

1) There are two modes how GPIOTE can work: using PIN or PORT events. PIN events can be set individually for up to 8 pins to monitor rising/falling/both edges, the response is very fast, but it has a disadvantage - relatively high power consumption because it requires high-frequency clock to remain active.
PORT event is set for the whole port and can be configured only to monitor high or low pin state (though logic similar to PIN event is emulated in gpiote library), the response is slower, but power consumption is very low, and it can be used to wake up device from power-down mode.
The bool value you've asked about chooses mode - true for PIN event, false for PORT event.

2) You cannot set two interrupt handlers for pin change event, but gpiote driver passes pin state to your handler - there's no need to have two different handlers.

3) GPIO works like in any other microcontroller - you can read and control pin state, direction, pullup/pulldown by software. GPIOTE is mainly intended to interact with other peripheral modules through events and tasks - a very powerful mechanism. You can read about tasks, events and PPI here, here and here.

RE: Trying to define 2 interrupt handlers for the same pin, one for up one for down

ziv123 — Mon, 18 May 2020 12:21:38 GMT

well i have found that i can use "nrf_gpio_pin_read()" on the pin in the pin in handler, but i wonder if that is the only or the best way to achive that

i have tried to change the action parameter of the handler and it seems it will not change after init so it is not clear why it is passed to the handler function in the example