/** * @file ws2812.c * @author Austin Glaser * @brief WS2812 LED driver * * Copyright (C) 2016 Austin Glaser * * This software may be modified and distributed under the terms * of the MIT license. See the LICENSE file for details. * * @todo Put in names and descriptions of variables which need to be defined to use this file * * @addtogroup WS2812 * @{ */ /* --- PRIVATE DEPENDENCIES ------------------------------------------------- */ // This Driver #include "ws2812.h" // Standard #include // ChibiOS #include "ch.h" #include "hal.h" // Application #include "board.h" #include "util.h" /* --- CONFIGURATION CHECK -------------------------------------------------- */ #if !defined(WS2812_LED_N) #error WS2812 LED chain length not specified #elif WS2812_LED_N <= 0 #error WS2812 LED chain length set to invalid value #endif #if !defined(WS2812_TIM_N) #error WS2812 timer not specified #endif #if defined(STM32F2XX) || defined(STM32F3XX) || defined(STM32F4XX) || defined(STM32F7XX) #if WS2812_TIM_N <= 2 #define WS2812_AF 1 #elif WS2812_TIM_N <= 5 #define WS2812_AF 2 #elif WS2812_TIM_N <= 11 #define WS2812_AF 3 #endif #elif !defined(WS2812_AF) #error WS2812_AF timer alternate function not specified #endif #if !defined(WS2812_TIM_CH) #error WS2812 timer channel not specified #elif WS2812_TIM_CH >= 4 #error WS2812 timer channel set to invalid value #endif /* --- PRIVATE CONSTANTS ---------------------------------------------------- */ #define WS2812_PWM_FREQUENCY (STM32_SYSCLK/2) /**< Clock frequency of PWM */ #define WS2812_PWM_PERIOD (WS2812_PWM_FREQUENCY/800000) /**< Clock period in ticks. 90/(72 MHz) = 1.25 uS (as per datasheet) */ /** * @brief Number of bit-periods to hold the data line low at the end of a frame * * The reset period for each frame must be at least 50 uS; so we add in 50 bit-times * of zeroes at the end. (50 bits)*(1.25 uS/bit) = 62.5 uS, which gives us some * slack in the timing requirements */ #define WS2812_RESET_BIT_N (50) #define WS2812_COLOR_BIT_N (WS2812_LED_N*24) /**< Number of data bits */ #define WS2812_BIT_N (WS2812_COLOR_BIT_N + WS2812_RESET_BIT_N) /**< Total number of bits in a frame */ /** * @brief High period for a zero, in ticks * * Per the datasheet: * - T0H: 0.200 uS to 0.500 uS, inclusive * - T0L: 0.650 uS to 0.950 uS, inclusive * * With a duty cycle of 22 ticks, we have a high period of 22/(72 MHz) = 3.06 uS, and * a low period of (90 - 22)/(72 MHz) = 9.44 uS. These values are within the allowable * bounds, and intentionally skewed as far to the low duty-cycle side as possible */ #define WS2812_DUTYCYCLE_0 (WS2812_PWM_FREQUENCY/(1000000000/350)) /** * @brief High period for a one, in ticks * * Per the datasheet: * - T0H: 0.550 uS to 0.850 uS, inclusive * - T0L: 0.450 uS to 0.750 uS, inclusive * * With a duty cycle of 56 ticks, we have a high period of 56/(72 MHz) = 7.68 uS, and * a low period of (90 - 56)/(72 MHz) = 4.72 uS. These values are within the allowable * bounds, and intentionally skewed as far to the high duty-cycle side as possible */ #define WS2812_DUTYCYCLE_1 (WS2812_PWM_FREQUENCY/(1000000000/800)) /* --- PRIVATE MACROS ------------------------------------------------------- */ /** * @brief Generates a reference to a numbered PWM driver * * @param[in] n: The driver (timer) number * * @return A reference to the driver */ #define PWMD(n) CONCAT_EXPANDED_SYMBOLS(PWMD, n) #define WS2812_PWMD PWMD(WS2812_TIM_N) /**< The PWM driver to use for the LED chain */ /** * @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given bit * * @param[in] led: The led index [0, @ref WS2812_LED_N) * @param[in] byte: The byte number [0, 2] * @param[in] bit: The bit number [0, 7] * * @return The bit index */ #define WS2812_BIT(led, byte, bit) (24*(led) + 8*(byte) + (7 - (bit))) /** * @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given red bit * * @note The red byte is the middle byte in the color packet * * @param[in] led: The led index [0, @ref WS2812_LED_N) * @param[in] bit: The bit number [0, 7] * * @return The bit index */ #define WS2812_RED_BIT(led, bit) WS2812_BIT((led), 1, (bit)) /** * @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given green bit * * @note The red byte is the first byte in the color packet * * @param[in] led: The led index [0, @ref WS2812_LED_N) * @param[in] bit: The bit number [0, 7] * * @return The bit index */ #define WS2812_GREEN_BIT(led, bit) WS2812_BIT((led), 0, (bit)) /** * @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given blue bit * * @note The red byte is the last byte in the color packet * * @param[in] led: The led index [0, @ref WS2812_LED_N) * @param[in] bit: The bit index [0, 7] * * @return The bit index */ #define WS2812_BLUE_BIT(led, bit) WS2812_BIT((led), 2, (bit)) /* --- PRIVATE VARIABLES ---------------------------------------------------- */ static uint8_t ws2812_frame_buffer[WS2812_BIT_N]; /**< Buffer for a frame */ /* --- PUBLIC FUNCTIONS ----------------------------------------------------- */ void ws2812_init(void) { // Initialize led frame buffer uint32_t i; for (i = 0; i < WS2812_COLOR_BIT_N; i++) ws2812_frame_buffer[i] = WS2812_DUTYCYCLE_0; // All color bits are zero duty cycle for (i = 0; i < WS2812_RESET_BIT_N; i++) ws2812_frame_buffer[i + WS2812_COLOR_BIT_N] = 0; // All reset bits are zero // Configure PA1 as AF output #ifdef WS2812_EXTERNAL_PULLUP palSetPadMode(PORT_WS2812, PIN_WS2812, PAL_MODE_ALTERNATE(WS2812_AF) | PAL_STM32_OTYPE_OPENDRAIN); #else palSetPadMode(PORT_WS2812, PIN_WS2812, PAL_MODE_ALTERNATE(WS2812_AF)); #endif // PWM Configuration #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 static const PWMConfig ws2812_pwm_config = { .frequency = WS2812_PWM_FREQUENCY, .period = WS2812_PWM_PERIOD, .callback = NULL, .channels = { [0 ... 3] = {.mode = PWM_OUTPUT_DISABLED, .callback = NULL}, // Channels default to disabled [WS2812_TIM_CH] = {.mode = PWM_OUTPUT_ACTIVE_HIGH, .callback = NULL}, // Turn on the channel we care about }, .cr2 = 0, .dier = TIM_DIER_UDE, // DMA on update event for next period }; #pragma GCC diagnostic pop // Restore command-line warning options // Configure DMA dmaStreamAllocate(WS2812_DMA_STREAM, 10, NULL, NULL); dmaStreamSetPeripheral(WS2812_DMA_STREAM, &(WS2812_PWMD.tim->CCR[WS2812_TIM_CH])); dmaStreamSetMemory0(WS2812_DMA_STREAM, ws2812_frame_buffer); dmaStreamSetTransactionSize(WS2812_DMA_STREAM, WS2812_BIT_N); dmaStreamSetMode(WS2812_DMA_STREAM, STM32_DMA_CR_DIR_M2P | STM32_DMA_CR_PSIZE_WORD | STM32_DMA_CR_MSIZE_BYTE | STM32_DMA_CR_MINC | STM32_DMA_CR_CIRC | STM32_DMA_CR_PL(3)); //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)); // Start DMA dmaStreamEnable(WS2812_DMA_STREAM); // Configure PWM // NOTE: It's required that preload be enabled on the timer channel CCR register. This is currently enabled in the // 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, // disable counting, enable the channel, and then make whatever configuration changes we need. pwmStart(&WS2812_PWMD, &ws2812_pwm_config); pwmEnableChannel(&WS2812_PWMD, WS2812_TIM_CH, 0); // Initial period is 0; output will be low until first duty cycle is DMA'd in } ws2812_err_t ws2812_write_led(uint32_t led_number, uint8_t r, uint8_t g, uint8_t b) { // Check for valid LED if (led_number >= WS2812_LED_N) return WS2812_LED_INVALID; // Write color to frame buffer uint32_t bit; for (bit = 0; bit < 8; bit++) { ws2812_frame_buffer[WS2812_RED_BIT(led_number, bit)] = ((r >> bit) & 0x01) ? WS2812_DUTYCYCLE_1 : WS2812_DUTYCYCLE_0; ws2812_frame_buffer[WS2812_GREEN_BIT(led_number, bit)] = ((g >> bit) & 0x01) ? WS2812_DUTYCYCLE_1 : WS2812_DUTYCYCLE_0; ws2812_frame_buffer[WS2812_BLUE_BIT(led_number, bit)] = ((b >> bit) & 0x01) ? WS2812_DUTYCYCLE_1 : WS2812_DUTYCYCLE_0; } // Success return WS2812_SUCCESS; } /** @} addtogroup WS2812 */ void ws2812_setleds(LED_TYPE *ledarray, uint16_t number_of_leds) { uint8_t i = 0; while (i < number_of_leds) { ws2812_write_led(i, ledarray[i].r, ledarray[i].g, ledarray[i].b); i++; } } void ws2812_setleds_rgbw(LED_TYPE *ledarray, uint16_t number_of_leds) { }