GPIO

The Voltix Module/Board has 11 digital GPIO pins. The API allows configuring pins as input or output. Outputs can be controlled similar to any other battery-powered device. Inputs can always be read with voltix_gpio_read(unsigned int pin) or the application can wait for a specified level on the pin with voltix_gpio_wait_level(...).

Important

Always check the return code of voltix_gpio_wait_level(...) to distinguish between a power failure (VOLTIX_ERR_RESET) and an actual level detection event (VOLTIX_SUCCESS).

Example usage

 1#include "voltix.h"
 2#include "voltix_gpio.h"
 3#include "voltix_timing.h"
 4
 5#define PIN_BUTTON PIN_D6
 6
 7void lateinit(void) {
 8  voltix_gpio_cfg_output(PIN_LED_CTRL);
 9}
10
11int main(void) {
12  for (;;) {
13    /* Wait for low level on button */
14    voltix_gpio_wait_level(PIN_BUTTON, VOLTIX_GPIO_LEVEL_LOW, VOLTIX_GPIO_IN_PULLUP);
15    /* Disable the pullup to save energy */
16    voltix_gpio_cfg_disable(PIN_BUTTON);
17
18    /* Blink LED for ~150us */
19    voltix_gpio_set(PIN_LED_CTRL);
20    voltix_sleep_ticks(5);
21    voltix_gpio_clear(PIN_LED_CTRL);
22    /* Wait until capacitor is recharged */
23    voltix_wait_cap_charged();
24  }
25}

API Reference

enum voltix_gpio_in_pull_t

GPIO input pullup configuration.

Values:

enumerator VOLTIX_GPIO_IN_PULLUP

Pullup resistor active.

enumerator VOLTIX_GPIO_IN_PULLDOWN

Pulldown resisotr active.

enumerator VOLTIX_GPIO_IN_NOPULL

No pullup/pulldown resistor active.

enum voltix_gpio_level_t

GPIO levels.

Values:

enumerator VOLTIX_GPIO_LEVEL_LOW

GPIO level high.

enumerator VOLTIX_GPIO_LEVEL_HIGH

GPIO level low.

void voltix_gpio_init(void)

Initializes GPIO. Must be called once after reset before GPIO interrupt functionality can be used.

voltix_rc_t voltix_gpio_wait_level(unsigned int pin, voltix_gpio_level_t level, voltix_gpio_in_pull_t pull)

Waits in low power mode until level is detected on pin.

CAUTION: The pin remains in the specified pull configuration after the function returns.

Parameters:

  • pin – Pin number.

  • level – Level to wait for.

  • pull – Pullup configuration.

Return values:

  • VOLTIX_SUCCESS – Specified level detected on pin.

  • VOLTIX_ERR_RESET – Reset occured while waiting for level.

static inline void voltix_gpio_cfg_output(unsigned int pin)

Configures pin as output.

Parameters:

pin – Pin number.

static inline void voltix_gpio_cfg_input(unsigned int pin, voltix_gpio_in_pull_t pull)

Configures pin as output.

Parameters:

  • pin – Pin number.

  • pull – Type of pull resistor.

static inline void voltix_gpio_cfg_disable(unsigned int pin)

Configures the pin for high impedance and disconnects the input buffer.

Parameters:

pin – Pin number.

static inline void voltix_gpio_set(unsigned int pin)

Sets output pin to logic high.

Parameters:

pin – Pin number.

static inline void voltix_gpio_clear(unsigned int pin)

Sets output pin to logic low.

Parameters:

pin – Pin number.

static inline void voltix_gpio_toggle(unsigned int pin)

Toggles logic state of output pin.

Parameters:

pin – Pin number.

static inline uint32_t voltix_gpio_read(unsigned int pin)

Reads logic state of input pin.

Parameters:

pin – Pin number.

Returns:

uint32_t 1 if logic high, 0 if logic low

static inline uint32_t voltix_gpio_is_set(unsigned int pin)

Reads logic state of output pin.

Parameters:

pin – Pin number.

Returns:

uint32_t 1 if logic high, 0 if logic low