zephyr

History

Kumar Gala a614a026b7 dts: Rename DT_._GPIO_ to DT_._GPIOS_ Convert DT_._GPIO_{CONTROLLER,PIN,FLAGS} -> DT_._GPIOS_{CONTROLLER,PIN,FLAGS) Used the following commands to make these conversions: git grep -l DT_._GPIO_CONTROLLER \| xargs sed -i 's/DT_\(.\)_GPIO_CONTROLLER/DT_\1_GPIOS_CONTROLLER/g' git grep -l DT_._GPIO_PIN \| xargs sed -i 's/DT_\(.\)_GPIO_PIN/DT_\1_GPIOS_PIN/g' git grep -l DT_._GPIO_FLAGS \| xargs sed -i 's/DT_\(.\)_GPIO_FLAGS/DT_\1_GPIOS_FLAGS/g' Signed-off-by: Kumar Gala <kumar.gala@linaro.org>		2019-06-27 13:02:34 -05:00
..
src	samples: Add 'U' to unsigned variable assignments	2018-12-04 22:51:56 -05:00
CMakeLists.txt	license: cleanup: add SPDX Apache-2.0 license identifier	2019-04-07 08:45:22 -04:00
prj.conf
README.rst	samples/basic: Update readme for blinky/button/disco	2018-12-26 09:46:59 -05:00
sample.yaml	dts: Rename DT_._GPIO_ to DT_._GPIOS_	2019-06-27 13:02:34 -05:00

README.rst

.. _button-sample:

Button demo
###########

Overview
********

A simple button demo showcasing the use of GPIO input with interrupts.

Requirements
************

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 :file:`board.h` must define the following variables:

- SW0_GPIO_NAME (or SW0_GPIO_CONTROLLER)
- SW0_GPIO_PIN

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:

.. zephyr-app-commands::
   :zephyr-app: samples/basic/button
   :board: nucleo_f103rb
   :goals: build
   :compact:

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.