/* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*
*/
/** library to drive a WS2812B LED chain (code)
* @file led_ws2812b.c
* @author King Kévin
* @date 2016-2017
* @note peripherals used: SPI @ref led_ws2812b_spi, timer @ref led_ws2812b_timer, DMA (for SPI MISO)
*/
/* standard libraries */
#include // standard integer types
#include // general utilities
/* STM32 (including CM3) libraries */
#include // Cortex M3 utilities
#include // real-time control clock library
#include // general purpose input output library
#include // SPI library
#include // timer library
#include // DMA library
#include // interrupt handler
#include "led_ws2812b.h" // LED WS2812B library API
#include "global.h" // common methods
/** peripheral configuration */
/** @defgroup led_ws2812b_spi SPI peripheral used to control the WS2812B LEDs
* @{
*/
#define LED_WS2812B_SPI 1 /**< SPI peripheral */
/** @} */
/** @defgroup led_ws2812b_timer timer peripheral used to generate SPI clock
* @{
*/
#define LED_WS2812B_TIMER 3 /**< timer peripheral */
#define LED_WS2812B_CLK_CH 3 /**< timer channel to output PWM (PB0), connect to SPI clock input */
#define LED_WS2812B_TIMER_OC TIM_OC3 /**< timer output compare used to set PWM frequency */
/** @} */
/** bit template to encode one byte to be shifted out by SPI to the WS2812B LEDs
* @details For each WS2812B bit which needs to be transfered we require to transfer 3 SPI bits.
* The first SPI bit is the high start of the WS2812B bit frame.
* The second SPI bit determines if the WS2812B bit is a 0 or 1.
* The third SPI bit is the last part of the WS2812B bit frame, which is always low.
* The binary pattern is 0b100100100100100100100100
*/
#define LED_WS2812B_SPI_TEMPLATE 0x924924
uint8_t led_ws2812b_data[LED_WS2812B_LEDS*3*3+40*3/8+1] = {0}; /**< data encoded to be shifted out by SPI for the WS2812B, plus the 50us reset (~40 data bits) */
static volatile bool transmit_flag = false; /**< flag set in software when transmission started, clear by interrupt when transmission completed */
void led_ws2812b_set_rgb(uint16_t led, uint8_t red, uint8_t green, uint8_t blue)
{
// verify the led exists
if (led>=LED_WS2812B_LEDS) {
return;
}
// wait for transmission to complete before changing the color
while (transmit_flag) {
__WFI();
}
const uint8_t colors[] = {green, red, blue}; // color order for the WS2812B
const uint8_t pattern_bit[] = {0x02, 0x10, 0x80, 0x04, 0x20, 0x01, 0x08, 0x40}; // which bit to change in the pattern
const uint8_t pattern_byte[] = {2,2,2,1,1,0,0,0}; // in which byte in the pattern to write the pattern bit
for (uint8_t color=0; color>16);
led_ws2812b_data[i*3+1] = (uint8_t)(LED_WS2812B_SPI_TEMPLATE>>8);
led_ws2812b_data[i*3+2] = (uint8_t)(LED_WS2812B_SPI_TEMPLATE>>0);
}
// fill remaining with with 0 to encode the reset code
for (uint16_t i=LED_WS2812B_LEDS*3*3; i