A simple button demo showcasing the use of GPIO input with interrupts.
The demo assumes that a push button is connected to one of GPIO lines. The sample code is configured to work on boards with user defined buttons and that have defined the SW0_* variables.
To use this sample, you will require a board that defines the user switch in its
header file. The
board.h must define the following variables:
- SW0_GPIO_NAME (or DT_ALIAS_SW0_GPIOS_CONTROLLER)
Alternatively, this could also be done by defining ‘sw0’ alias in the board device tree description file.
Building and Running¶
This sample can be built for multiple boards, in this example we will build it for the nucleo_f103rb board:
west build -b nucleo_f103rb samples/basic/button
Using CMake and ninja:
cmake -B build -GNinja -DBOARD=nucleo_f103rb samples/basic/button ninja -C build
After startup, the program looks up a predefined GPIO device, and configures the pin in input mode, enabling interrupt generation on falling edge. During each iteration of the main loop, the state of GPIO line is monitored and printed to the serial console. When the input button gets pressed, the interrupt handler will print an information about this event along with its timestamp.