RP2040_Resources/1_Basic_GPIO/blinky.md

Blinky

The classic, the helloWorld of embedded programming. This program turns the LED on and off periodically.

Initial steps:

• Create new project with project generator.
• Open the project folder in VSCode.
• Build the project by pressing the build button at the bottom and select the option with arm-none-eabi.
• Make sure the build exits with code 0.

Basic Code:

int main()
{
    stdio_init_all();

    const uint OnBoardLED = PICO_DEFAULT_LED_PIN;
    gpio_init(OnBoardLED);
    gpio_set_dir(OnBoardLED, GPIO_OUT);
    while (true){
        gpio_put(OnBoardLED, true);
        sleep_ms(500);
        gpio_put(OnBoardLED, false);
        sleep_ms(500);
    }
}

Explanation:

stdio_init_all(): initialize stuff

OnBoardLED = PICO_DEFAULT_LED_PIN: Get the GPIO number of onboard LED. Remember this is GPIO Number, NOT PIN NUMBER.

gpio_init(OnBoardLED): Initialize that GPIO pin.

gpio_set_dir(OnBoardLED, GPIO_OUT): Set GPIO direction (GPIO_OUT for writing and GPIO_IN for reading).

while (true){}: Super loop of the program

gpio_put(OnBoardLED, true): Set OnBoardLED pin to on (true to turn on/set to high/voltage to VDD, false to turn off/set to low/voltage to GND)

Pico logic HIGH voltage is 3.3v and LOW voltage is 0v.

sleep_ms(500): sleep for 500ms.

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