How To: GPIO Pins

You can use many GPIO pins (General Purpose Input/Output pins) to connect the Core Module with the outside world. The pins are described in the Header Pinout. The pins in SDK have the names TWR_GPIO_P0 to TWR_GPIO_P17. There are also two special pins dedicated to TWR_GPIO_LED and TWR_GPIO_BUTTON.

References

GPIO SDK Module
GitHub Repository Example

info

This example will turn on the LED on the Core Module. The usual and more comfortable way to control LED is to use twr_led code, but we use twr_gpio for now to explain the GPIO basics.

GPIO as Output Code Example

#include <application.h>

void application_init(void)
{
    twr_gpio_init(TWR_GPIO_LED);
    twr_gpio_set_mode(TWR_GPIO_LED, TWR_GPIO_MODE_OUTPUT);
    twr_gpio_set_output(TWR_GPIO_LED, 1);
}

info

This example will read the button state and based on that the LED will be set to the ON/OFF state.

GPIO Input and Output Code Example

#include <application.h>

void application_init(void)
{
    twr_gpio_init(TWR_GPIO_LED);
    twr_gpio_set_mode(TWR_GPIO_LED, TWR_GPIO_MODE_OUTPUT);

    twr_gpio_init(TWR_GPIO_BUTTON);
    twr_gpio_set_mode(TWR_GPIO_BUTTON, TWR_GPIO_MODE_INPUT);

    // The Core Module has hardware pull-down so next call is commented out
    // twr_gpio_set_pull(TWR_GPIO_BUTTON, TWR_GPIO_PULL_DOWN);
}

void application_task()
{
    uint8_t button_state = twr_gpio_get_input(TWR_GPIO_BUTTON);
    twr_gpio_set_output(TWR_GPIO_LED, button_state);

    // Repeat this task again after 10 ms
    twr_scheduler_plan_current_relative(10);
}

References​

References