lpd8808.c
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/*
* Copyright (C) 2016 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup drivers_lpd8808
* @{
*
* @file
* @brief LPD8808 based LED strip driver implementation
*
* @author Hauke Petersen <mail@haukepetersen.de>
*
* @}
*/
#include <string.h>
#include "lpd8808.h"
/**
* @brief Shift a single byte to the strip
*
* @param[in] dev device to use
* @param[in] d byte to shift out
*/
static void put_byte(const lpd8808_t *dev, uint8_t d)
{
for (int i = 0; i < 8; i++) {
gpio_write(dev->pin_dat, d & 0x80);
gpio_set(dev->pin_clk);
gpio_clear(dev->pin_clk);
d <<= 1;
}
}
/**
* @brief Flush the previous input
*
* LPD8808 based strips need to be flushed after loading values for each LED.
* This is done by feeding the strip with one zero byte for every 32 LEDs on
* the strip.
*
* @param[in] dev device to flush
*/
static void flush(const lpd8808_t *dev)
{
for (int i = 0; i < ((dev->led_cnt + 31) / 32); i++) {
put_byte(dev, 0);
}
}
int lpd8808_init(lpd8808_t *dev, const lpd8808_params_t *params)
{
memcpy(dev, params, sizeof(lpd8808_params_t));
/* initialize pins */
gpio_init(dev->pin_dat, GPIO_OUT);
gpio_init(dev->pin_clk, GPIO_OUT);
flush(dev);
return 0;
}
void lpd8808_load_rgb(const lpd8808_t *dev, color_rgb_t vals[])
{
for (int i = 0; i < dev->led_cnt; i++) {
put_byte(dev, ((vals[i].g >> 1) | 0x80));
put_byte(dev, ((vals[i].r >> 1) | 0x80));
put_byte(dev, ((vals[i].b >> 1) | 0x80));
}
flush(dev);
}