273 lines
11 KiB
C
273 lines
11 KiB
C
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/**
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* @file ws2812.c
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* @author Austin Glaser <austin.glaser@gmail.com>, Joerg Wangemann <joerg.wangemann@gmail.com>
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* @brief WS2812 LED driver
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*
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* Copyright (C) 2016 Austin Glaser, 2017 Joerg Wangemann
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*
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* This software may be modified and distributed under the terms
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* of the MIT license. See the LICENSE file for details.
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*
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* @todo Put in names and descriptions of variables which need to be defined to use this file
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*
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* @addtogroup WS2812
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* @{
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*/
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/* --- PRIVATE DEPENDENCIES ------------------------------------------------- */
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// This Driver
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#include "ws2812_f4.h"
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// Standard
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#include <stdint.h>
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// ChibiOS
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#include "ch.h"
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#include "hal.h"
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#include "wait.h"
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// Application
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//#include "board.h"
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// TODO: Add these #define's to the headers of your project.
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// Pin, timer and dma are all connected, check them all if you change one.
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// Tested with STM32F4, working at 144 or 168 MHz.
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//#define WS2812_LED_N 2 // Number of LEDs
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//#define PORT_WS2812 GPIOB
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//#define PIN_WS2812 9
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//#define WS2812_TIM_N 4 // timer, 1-11
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//#define WS2812_TIM_CH 3 // timer channel, 0-3
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//#define WS2812_DMA_STREAM STM32_DMA1_STREAM2 // DMA stream for TIMx_UP (look up in reference manual under DMA Channel selection)
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//#define WS2812_DMA_CHANNEL 6 // DMA channel for TIMx_UP
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// The WS2812 expects 5V signal level (or at least 0.7 * VDD). Sometimes it works
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// with a 3V signal level, otherwise the easiest way to get the signal level to 5V
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// is to add an external pullup resistor from the DI pin to 5V (10k will do) and
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// configure the pin as open drain.
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// (An SMD resistor is easily solders on the connections of a light strip)
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// Uncomment the next line if an external pullup resistor is used.
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//#define WS2812_EXTERNAL_PULLUP
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/* --- CONFIGURATION CHECK -------------------------------------------------- */
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#if !defined(WS2812_LED_N)
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#error WS2812 LED chain length not specified
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#elif WS2812_LED_N <= 0
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#error WS2812 LED chain length set to invalid value
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#endif
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#if !defined(WS2812_TIM_N)
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#error WS2812 timer not specified
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#endif
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#if defined(STM32F2XX) || defined(STM32F4XX) || defined(STM32F7XX)
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#if WS2812_TIM_N <= 2
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#define WS2812_AF 1
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#elif WS2812_TIM_N <= 5
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#define WS2812_AF 2
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#elif WS2812_TIM_N <= 11
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#define WS2812_AF 3
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#endif
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#elif !defined(WS2812_AF)
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#error WS2812_AF timer alternate function not specified
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#endif
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#if !defined(WS2812_TIM_CH)
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#error WS2812 timer channel not specified
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#elif WS2812_TIM_CH >= 4
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#error WS2812 timer channel set to invalid value
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#endif
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/* --- PRIVATE CONSTANTS ---------------------------------------------------- */
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#define WS2812_PWM_FREQUENCY (STM32_SYSCLK/2) /**< Clock frequency of PWM, must be valid with respect to system clock! */
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#define WS2812_PWM_PERIOD (WS2812_PWM_FREQUENCY/800000) /**< Clock period in ticks. 1 / 800kHz = 1.25 uS (as per datasheet) */
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/**
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* @brief Number of bit-periods to hold the data line low at the end of a frame
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*
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* The reset period for each frame must be at least 50 uS; so we add in 50 bit-times
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* of zeroes at the end. (50 bits)*(1.25 uS/bit) = 62.5 uS, which gives us some
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* slack in the timing requirements
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*/
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#define WS2812_RESET_BIT_N (50)
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#define WS2812_COLOR_BIT_N (WS2812_LED_N*24) /**< Number of data bits */
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#define WS2812_BIT_N (WS2812_COLOR_BIT_N + WS2812_RESET_BIT_N) /**< Total number of bits in a frame */
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/**
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* @brief High period for a zero, in ticks
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*
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* Per the datasheet:
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* WS2812:
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* - T0H: 200 nS to 500 nS, inclusive
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* - T0L: 650 nS to 950 nS, inclusive
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* WS2812B:
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* - T0H: 200 nS to 500 nS, inclusive
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* - T0L: 750 nS to 1050 nS, inclusive
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*
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* The duty cycle is calculated for a high period of 350 nS.
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*/
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#define WS2812_DUTYCYCLE_0 (WS2812_PWM_FREQUENCY/(1000000000/450))
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/**
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* @brief High period for a one, in ticks
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*
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* Per the datasheet:
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* WS2812:
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* - T1H: 550 nS to 850 nS, inclusive
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* - T1L: 450 nS to 750 nS, inclusive
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* WS2812B:
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* - T1H: 750 nS to 1050 nS, inclusive
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* - T1L: 200 nS to 500 nS, inclusive
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*
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* The duty cycle is calculated for a high period of 800 nS.
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* This is in the middle of the specifications of the WS2812 and WS2812B.
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*/
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#define WS2812_DUTYCYCLE_1 (WS2812_PWM_FREQUENCY/(1000000000/900))
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/* --- PRIVATE MACROS ------------------------------------------------------- */
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/**
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* @brief Generates a reference to a numbered PWM driver
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*
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* @param[in] n: The driver (timer) number
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*
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* @return A reference to the driver
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*/
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#define PWMD(n) CONCAT_EXPANDED_SYMBOLS(PWMD, n)
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#define WS2812_PWMD PWMD(WS2812_TIM_N) /**< The PWM driver to use for the LED chain */
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/**
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* @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given bit
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*
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* @param[in] led: The led index [0, @ref WS2812_LED_N)
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* @param[in] byte: The byte number [0, 2]
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* @param[in] bit: The bit number [0, 7]
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*
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* @return The bit index
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*/
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#define WS2812_BIT(led, byte, bit) (24*(led) + 8*(byte) + (7 - (bit)))
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/**
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* @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given red bit
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*
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* @note The red byte is the middle byte in the color packet
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*
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* @param[in] led: The led index [0, @ref WS2812_LED_N)
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* @param[in] bit: The bit number [0, 7]
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*
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* @return The bit index
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*/
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#define WS2812_RED_BIT(led, bit) WS2812_BIT((led), 1, (bit))
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/**
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* @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given green bit
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*
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* @note The green byte is the first byte in the color packet
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*
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* @param[in] led: The led index [0, @ref WS2812_LED_N)
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* @param[in] bit: The bit number [0, 7]
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*
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* @return The bit index
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*/
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#define WS2812_GREEN_BIT(led, bit) WS2812_BIT((led), 0, (bit))
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/**
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* @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given blue bit
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*
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* @note The blue byte is the last byte in the color packet
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*
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* @param[in] led: The led index [0, @ref WS2812_LED_N)
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* @param[in] bit: The bit index [0, 7]
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*
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* @return The bit index
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*/
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#define WS2812_BLUE_BIT(led, bit) WS2812_BIT((led), 2, (bit))
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/* --- PRIVATE VARIABLES ---------------------------------------------------- */
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static uint32_t ws2812_frame_buffer[WS2812_BIT_N + 1]; /**< Buffer for a frame */
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/* --- PUBLIC FUNCTIONS ----------------------------------------------------- */
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/*
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* Gedanke: Double-buffer type transactions: double buffer transfers using two memory pointers for
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the memory (while the DMA is reading/writing from/to a buffer, the application can
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write/read to/from the other buffer).
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*/
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void ws2812_init(void)
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{
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// Initialize led frame buffer
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uint32_t i;
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for (i = 0; i < WS2812_COLOR_BIT_N; i++) ws2812_frame_buffer[i] = WS2812_DUTYCYCLE_0; // All color bits are zero duty cycle
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for (i = 0; i < WS2812_RESET_BIT_N; i++) ws2812_frame_buffer[i + WS2812_COLOR_BIT_N] = 0; // All reset bits are zero
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// Configure pin as AF output. If there's an external pull up resistor the signal level is brought to 5V using open drain mode.
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#ifdef WS2812_EXTERNAL_PULLUP
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palSetPadMode(PORT_WS2812, PIN_WS2812, PAL_MODE_ALTERNATE(WS2812_AF) | PAL_STM32_OTYPE_OPENDRAIN);
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#else
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palSetPadMode(PORT_WS2812, PIN_WS2812, PAL_MODE_ALTERNATE(WS2812_AF) | PAL_STM32_OTYPE_PUSHPULL); //PAL_MODE_STM32_ALTERNATE_PUSHPULL);
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#endif
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//palClearPad(PORT_WS2812, PIN_WS2812);
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//wait_ms(1);
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// PWM Configuration
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#pragma GCC diagnostic ignored "-Woverride-init" // Turn off override-init warning for this struct. We use the overriding ability to set a "default" channel config
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static const PWMConfig ws2812_pwm_config = {
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.frequency = WS2812_PWM_FREQUENCY,
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.period = WS2812_PWM_PERIOD, //Mit dieser Periode wird UDE-Event erzeugt und ein neuer Wert (Länge WS2812_BIT_N) vom DMA ins CCR geschrieben
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.callback = NULL,
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.channels = {
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[0 ... 3] = {.mode = PWM_OUTPUT_DISABLED, .callback = NULL}, // Channels default to disabled
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[WS2812_TIM_CH] = {.mode = PWM_OUTPUT_ACTIVE_HIGH, .callback = NULL}, // Turn on the channel we care about
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},
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.cr2 = 0,
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.dier = TIM_DIER_UDE, // DMA on update event for next period
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};
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#pragma GCC diagnostic pop // Restore command-line warning options
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// Configure DMA
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//dmaInit(); // Joe added this
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dmaStreamAllocate(WS2812_DMA_STREAM, 10, NULL, NULL);
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dmaStreamSetPeripheral(WS2812_DMA_STREAM, &(WS2812_PWMD.tim->CCR[WS2812_TIM_CH])); // Ziel ist der An-Zeit im Cap-Comp-Register
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dmaStreamSetMemory0(WS2812_DMA_STREAM, ws2812_frame_buffer);
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dmaStreamSetTransactionSize(WS2812_DMA_STREAM, WS2812_BIT_N);
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dmaStreamSetMode(WS2812_DMA_STREAM,
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STM32_DMA_CR_CHSEL(WS2812_DMA_CHANNEL) | STM32_DMA_CR_DIR_M2P | STM32_DMA_CR_PSIZE_WORD | STM32_DMA_CR_MSIZE_WORD |
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STM32_DMA_CR_MINC | STM32_DMA_CR_CIRC | STM32_DMA_CR_PL(3));
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// M2P: Memory 2 Periph; PL: Priority Level
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// Start DMA
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dmaStreamEnable(WS2812_DMA_STREAM);
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// Configure PWM
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// NOTE: It's required that preload be enabled on the timer channel CCR register. This is currently enabled in the
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// ChibiOS driver code, so we don't have to do anything special to the timer. If we did, we'd have to start the timer,
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// disable counting, enable the channel, and then make whatever configuration changes we need.
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pwmStart(&WS2812_PWMD, &ws2812_pwm_config);
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pwmEnableChannel(&WS2812_PWMD, WS2812_TIM_CH, 0); // Initial period is 0; output will be low until first duty cycle is DMA'd in
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}
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ws2812_err_t ws2812_write_led(uint32_t led_number, uint8_t r, uint8_t g, uint8_t b)
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{
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// Check for valid LED
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if (led_number > WS2812_LED_N) return WS2812_LED_INVALID;
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// Write color to frame buffer
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for (uint32_t bit = 0; bit < 8; bit++) {
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ws2812_frame_buffer[WS2812_RED_BIT(led_number, bit)] = ((r >> bit) & 0x01) ? WS2812_DUTYCYCLE_1 : WS2812_DUTYCYCLE_0;
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ws2812_frame_buffer[WS2812_GREEN_BIT(led_number, bit)] = ((g >> bit) & 0x01) ? WS2812_DUTYCYCLE_1 : WS2812_DUTYCYCLE_0;
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ws2812_frame_buffer[WS2812_BLUE_BIT(led_number, bit)] = ((b >> bit) & 0x01) ? WS2812_DUTYCYCLE_1 : WS2812_DUTYCYCLE_0;
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}
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// Success
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return WS2812_SUCCESS;
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}
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void ws2812_setleds(LED_TYPE *ledarray, uint16_t number_of_leds)
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{
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for(int i = 0; i < number_of_leds; i++) {
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ws2812_write_led(i, ledarray[i].r, ledarray[i].g, ledarray[i].b);
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}
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}
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/** @} addtogroup WS2812 */
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