PWM DMA based RGB Underglow for STM32 (#7928)
* Add pwm ws2812 driver * Add docs for pwm ws2812 driver * Update ws2812_pwm for ChibiOS 19 Co-Authored-By: Nick Brassel <nick@tzarc.org> Co-authored-by: Nick Brassel <nick@tzarc.org>refactor_process_record_kb_user 0.8.6
Joel Challis
5 years ago
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f74c769a19
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#error("NOT SUPPORTED") |
#include "ws2812.h" |
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#include "quantum.h" |
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#include "hal.h" |
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/* Adapted from https://github.com/joewa/WS2812-LED-Driver_ChibiOS/ */ |
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#ifdef RGBW |
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# error "RGBW not supported" |
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#endif |
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#ifndef WS2812_PWM_DRIVER |
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# define WS2812_PWM_DRIVER PWMD2 // TIMx
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#endif |
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#ifndef WS2812_PWM_CHANNEL |
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# define WS2812_PWM_CHANNEL 2 // Channel
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#endif |
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#ifndef WS2812_PWM_PAL_MODE |
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# define WS2812_PWM_PAL_MODE 2 // DI Pin's alternate function value
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#endif |
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#ifndef WS2812_DMA_STREAM |
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# define WS2812_DMA_STREAM STM32_DMA1_STREAM2 // DMA Stream for TIMx_UP
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#endif |
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#ifndef WS2812_DMA_CHANNEL |
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# define WS2812_DMA_CHANNEL 2 // DMA Channel for TIMx_UP
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#endif |
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#ifndef WS2812_PWM_TARGET_PERIOD |
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//# define WS2812_PWM_TARGET_PERIOD 800000 // Original code is 800k...?
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# define WS2812_PWM_TARGET_PERIOD 80000 // TODO: work out why 10x less on f303/f4x1
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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 / WS2812_PWM_TARGET_PERIOD) /**< 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 (RGBLED_NUM * 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 / 350)) |
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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 / 800)) |
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/* --- PRIVATE MACROS ------------------------------------------------------- */ |
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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 RGBLED_NUM) |
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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 RGBLED_NUM) |
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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 red 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 RGBLED_NUM) |
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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 red 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 RGBLED_NUM) |
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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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// 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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#if defined(USE_GPIOV1) |
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palSetLineMode(RGB_DI_PIN, PAL_MODE_STM32_ALTERNATE_PUSHPULL); |
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#else |
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palSetLineMode(RGB_DI_PIN, PAL_MODE_ALTERNATE(WS2812_PWM_PAL_MODE) | PAL_STM32_OSPEED_HIGHEST | PAL_STM32_PUPDR_FLOATING); |
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#endif |
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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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{ |
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[0 ... 3] = {.mode = PWM_OUTPUT_DISABLED, .callback = NULL}, // Channels default to disabled
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[WS2812_PWM_CHANNEL - 1] = {.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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dmaStreamAlloc(WS2812_DMA_STREAM - STM32_DMA1_STREAM1, 10, NULL, NULL); |
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dmaStreamSetPeripheral(WS2812_DMA_STREAM, &(WS2812_PWM_DRIVER.tim->CCR[WS2812_PWM_CHANNEL - 1])); // 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, STM32_DMA_CR_CHSEL(WS2812_DMA_CHANNEL) | STM32_DMA_CR_DIR_M2P | STM32_DMA_CR_PSIZE_WORD | STM32_DMA_CR_MSIZE_WORD | 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_PWM_DRIVER, &ws2812_pwm_config); |
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pwmEnableChannel(&WS2812_PWM_DRIVER, WS2812_PWM_CHANNEL - 1, 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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void ws2812_write_led(uint16_t led_number, uint8_t r, uint8_t g, uint8_t b) { |
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// Write color to frame buffer
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for (uint8_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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} |
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// Setleds for standard RGB
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void ws2812_setleds(LED_TYPE* ledarray, uint16_t leds) { |
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static bool s_init = false; |
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if (!s_init) { |
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ws2812_init(); |
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s_init = true; |
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} |
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for (uint16_t i = 0; i < 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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