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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

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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);}

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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);}