zephyr

History

Keith Packard 0b90fd5adf samples, tests, boards: Switch main return type from void to int As both C and C++ standards require applications running under an OS to return 'int', adapt that for Zephyr to align with those standard. This also eliminates errors when building with clang when not using -ffreestanding, and reduces the need for compiler flags to silence warnings for both clang and gcc. Most of these changes were automated using coccinelle with the following script: @@ @@ - void + int main(...) { ... - return; + return 0; ... } Approximately 40 files had to be edited by hand as coccinelle was unable to fix them. Signed-off-by: Keith Packard <keithp@keithp.com>		2023-04-14 07:49:41 +09:00
..
boards	samples: Remove label property from devicetree overlays	2022-08-01 17:59:32 +02:00
src	samples, tests, boards: Switch main return type from void to int	2023-04-14 07:49:41 +09:00
CMakeLists.txt	cmake: increase minimal required version to 3.20.0	2021-08-20 09:47:34 +02:00
README.rst	boards: nrf52840_pca10056: Rename board to nrf52840dk_nrf52840	2020-03-27 09:14:08 +01:00
prj.conf	drivers: led: Remove unnecessary Kconfig settings	2022-08-11 17:46:43 +02:00
sample.yaml	sanitycheck: inclusive language	2020-08-27 07:04:07 -04:00

README.rst

.. _ht16k33:

HT16K33 LED driver with keyscan
###############################

Overview
********

This sample controls the LEDs connected to a `Holtek HT16K33`_
driver. The sample supports up to 128 LEDs connected to the
rows/columns of the HT16K33.

The LEDs are controlled using the following pattern:

 1. turn on all connected (up to 128) LEDs one-by-one
 2. blink the LEDs at 2 Hz, 1 Hz, and 0.5 Hz
 3. reduce the brightness gradually from 100% to 0%
 4. turn off all LEDs, restore 100% brightness, and start over

The sample logs keyscan events on the console.

Building and Running
********************

Build the application for the :ref:`nrf52840dk_nrf52840` board, and
connect a HT16K33 LED driver at address 0x70 on the I2C-0 bus.

.. zephyr-app-commands::
   :zephyr-app: samples/drivers/ht16k33
   :board: nrf52840dk_nrf52840
   :goals: build
   :compact:

For flashing the application, refer to the Flashing section of the
:ref:`nrf52840dk_nrf52840` board documentation.

References
**********

.. target-notes::

.. _Holtek HT16K33: http://www.holtek.com/productdetail/-/vg/HT16K33