flipperzero-firmware/wiki/examples/Blink-app.md

First, let's create a simple led blinking application.

Preparing for launch

We will use integrated LED. Look at the schematic:

This LED is connected between power rail and GPIO PA8, and we should configure this pin as an open drain to properly control the LED behaviour.

You can find GPIO API in target_*/flipper_hal.h. Or if you prefer to use Arduino API, you can find the bindings in core/flipper.h.

To work with the pin we should:

1. Create GpioPin instance and specify pin and port.
2. Configure mode of pin by pinMode function.
3. Control state of pin by digitalWrite function.

Creating application

1. Create a new file (for example, blink.c) in applications folder.
2. Create code like this:

#include "flipper.h"

void application_blink(void* p) {
    // create pin
    GpioPin led = {.pin = GPIO_PIN_8, .port = GPIOA};

    // configure pin
    pinMode(led, GpioModeOpenDrain);

    while(1) {
        digitalWrite(led, HIGH);
        delay(500);
        digitalWrite(led, LOW);
        delay(500);
    }
}

3. To start your application on Flipper startup, add it to the autorun:

   • in applications/startup.h add prototype of main application function:

   void application_blink(void* p);
   

   • add entry to FLIPPER_STARTUP array (pointer to application function and application name):

   const FlipperStartupApp FLIPPER_STARTUP[] = {
       #ifdef TEST
       {.app = flipper_test_app, .name = "test app"}
       #endif
   
       // user applications:
   
       , {.app = application_blink, .name = "blink"}  
   };
   

4. Add your application file to Makefile (for each target, target_lo/Makefile and target_f1/Makefile, we'll add one common makefile later):

# User application

C_SOURCES += ../applications/blink.c

Build and run for linux (target_lo):

docker-compose exec dev make -C target_lo

Run:

docker-compose exec dev target_lo/build/target_lo.

Linux version has no LED or GPIO, but we can see debug messages of how state of GPIO is changing:

You can also find source of this example in applications/examples/blink.c and run it by docker-compose exec dev make -C target_lo example_blink

Build for Flipper (board F1):

docker-compose exec dev make -C target_f1

Upload to microcontroller:

./target_f1/deploy.sh

Blink!

You can also compile by docker-compose exec dev make -C target_f1 example_blink