Bare Metal GPIOTE

The Bare Metal GPIOTE is a lightweight library to allow multiple users to share GPIOTE instances.

Overview

This library holds the nrfx GPIOTE instance data and handles initialization, ISR declaration, and IRQ connection of the available nrfx GPIOTE instances. The library allows for multiple users of the GPIOTE instances and lets them retrieve GPIOTE instances based on GPIO port numbers.

Note

You are expected to use the nrfx GPIOTE interface directly for all operations except declaring and initializing the GPIOTE instances themselves.

Configuration

The library is enabled using the Kconfig system. Set the CONFIG_BM_GPIOTE Kconfig option to enable the library.

Use the CONFIG_BM_GPIOTE_IRQ_PRIO Kconfig option to set the GPIOTE interrupt priority.

Set the CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS Kconfig option to match the number of simultaneous GPIOTE event handlers. The number of handlers applies for each GPIOTE instance and must account for all users, including Bare Metal drivers and libraries. To reduce the number of handlers required, it is recommended to use the same nrfx_gpiote_handler_config_t event handler and context for multiple pins on the same port if applicable.

Initialization

The library is initialized automatically on application startup.

Note

The nrfx_gpiote_init() function is called by this library to initialize the GPIOTE instances on application startup. The library does not provide any functionality for deinitializing the GPIOTE instances. Each nrfx GPIOTE instance can be reinitialized using the nrfx interface. In such case, make sure not to affect other users of the GPIOTE.

Usage

Call the bm_gpiote_instance_get() function to retrieve a pointer to the GPIOTE instance for the given GPIO port. Use the instance retrieved with the nrfx GPIOTE API.

The following sample shows how to set up an interrupt on the rising edge of a pin with GPIOTE:

#include <bm/bm_gpiote.h>
#include <nrfx_gpiote.h>

static void gpiote_evt_handler(nrfx_gpiote_pin_t pin, nrfx_gpiote_trigger_t action, void *ctx)
{
   printk("Event on pin %d\n", pin);
}

static const nrf_gpio_pin_pull_t pull_config = NRF_GPIO_PIN_PULLUP;
static const nrfx_gpiote_handler_config_t handler_config = {
   .handler = gpiote_evt_handler,
};
static const nrfx_gpiote_trigger_config_t trigger_config = {
   .trigger = NRFX_GPIOTE_TRIGGER_LOTOHI,
};
static const nrfx_gpiote_input_pin_config_t input_config = {
   .p_pull_config = &pull_config,
   .p_trigger_config = &trigger_config,
   .p_handler_config = &handler_config,
};
static nrfx_gpiote_pin_t pin;

static nrfx_gpiote_t *gpiote_inst = bm_gpiote_instance_get(NRF_PIN_NUMBER_TO_PORT(pin));

err = nrfx_gpiote_input_configure(gpiote_inst, pin, input_config);
if (err) {
   LOG_ERR("nrfx_gpiote_input_configure failed, err %d", err);
   return err;
}

For further details on the usage of the GPIOTE peripheral, see the nrfx GPIOTE API.

Dependencies

API documentation

Header file: include/bm/bm_gpiote.h
Source files: lib/bm_gpiote/

Bare Metal GPIOTE library API reference