STM32驱动全彩LED灯模块WS2812

WS2812全彩LED灯模块系列，可以进行级联实现灯带的效果，MCU端通过一个管脚可以控制所有级联的LED灯的不同发光颜色显示。

级联电路

WS2811(未集成LED）的级联电路如下所示：

WS2812（集成LED）的级联电路如下所示：

STM32是3.3V供电芯片，输出Push-Pull模式只有3.3V，WS2812采用5V供电，输入Vih为0.7*5=3.5V高于3.3V，所以STM32连接WS2812时要采用有FT耐5V电压的管脚，采用Open-drain的输出方式，并外部上拉1K电阻，实现与第一个WS2812的DI的连接，对于后面级联的WS2812，由前一级DO驱动5V信号输出，直接DO连接DI即可。
实现STM32驱动控制WS282的时序信号，由于时序输出翻转延迟达到了百纳秒级，需要硬件资源驱动的管脚输出，可以用SPI总线的MOSI实现。因为MCU的SPI总线资源较少，定时器资源相对较多，因此这里介绍采用TIM PWM方式的驱动实现。
以STM32F103C6T6为例，选择同时具有FT和TIM PWM输出特性的管脚，这里选择PB10:

连接关系简图：

时序说明

驱动器（STM32)输出RESET指示信号（>280us, 低电平有效）, 此信号为双目的，一则WS2812的DI输入识别到有大于280us的低电平信号, 则将之前配置的数据驱动输出给三色/三个LED。二则进入到等待状态，等待下一次的数据配置信号到来。
数据配置信号为24个位一组，对应R, G, B三色各256级深度，即R, G, B各用一个字节/8位表示，如下所示：

注意24位对应3个字节并非是R, G, B顺序输出，而是G, R, B顺序输出，每个字节是高位在前进行发送。
每个位的发送时序都是由高低电平组成，由高电平和低电平的相对时长判断该位是0还是1：

高电平和低电平有时长范围要求：

可以看出主要先规划短电平时长和宽电平时长，这里基于STM32F103的72MHz，可以在TIM分频出对应125ns的计数周期，所以选择短电平时长为125 * 3 = 375ns，选择宽电平时长为125 * 12 = 1500ns = 1.5us，后面进行工程配置和代码编写。

STM32工程配置

这里以STM32CUBEIDE开发平台对STM32F103C6T6芯片进行配置为例，首先建立基本工程并配置时钟主频为72MHz：

然后配置PB10为TIM PWM输出的Open-drain模式：

配置TIM时钟为8MHz，并配置PWM的参数：

这里需要注意，Output compare preload需要配置为Enable, 因为后面的时序逻辑里，会在当前周期的PWM输出时修改PWM输出的占空比，而这个占空比修改的施行是在下一个周期，并不再当前周期。
保存并产生基本工程代码：

STM32工程代码

驱动逻辑的实现主要是通过启动TIM PWM输出时，在不同的时刻控制PWM输出的占空比，如RESET指示信号的输出即为控制输出占空比为0，而逻辑1和逻辑0信号的输出则是在每个逻辑输出前调整PWM占空比以对应逻辑1和逻辑0。

代码里用到的纳秒级延时介绍：
STM32 纳秒级延时 (ns delay) 的指令延时实现方式及测定
代码里用到的半微秒级延时介绍：
STM32 HAL us delay（微秒延时）的指令延时实现方式及优化

代码实现单个LED模块驱动，需要驱动多个LED模块, 进行驱动函数扩展即可。完整的代码如下：

/* USER CODE BEGIN Header */
/********************************************************************************* @file           : main.c* @brief          : Main program body******************************************************************************* @attention** Copyright (c) 2022 STMicroelectronics.* All rights reserved.** This software is licensed under terms that can be found in the LICENSE file* in the root directory of this software component.* If no LICENSE file comes with this software, it is provided AS-IS.********************************************************************************/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes *//* USER CODE END Includes *//* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
__IO float semiusDelayBase;
void PY_semiusDelayTest(void)
{__IO uint32_t firstms, secondms;
__IO uint32_t counter = 0;firstms = HAL_GetTick()+1;secondms = firstms+1;while(uwTick!=firstms) ;while(uwTick!=secondms) counter++;semiusDelayBase = ((float)counter)/2000;
}void PY_Delay_semius_t(uint32_t Delay)
{__IO  uint32_t delayReg;
__IO  uint32_t semiusNum = (uint32_t)(Delay*semiusDelayBase);delayReg = 0;while(delayReg!=semiusNum) delayReg++;
}void PY_semiusDelayOptimize(void)
{__IO  uint32_t firstms, secondms;
__IO  float coe = 1.0;firstms = HAL_GetTick();PY_Delay_semius_t(2000000) ;secondms = HAL_GetTick();coe = ((float)1000)/(secondms-firstms);semiusDelayBase = coe*semiusDelayBase;
}void PY_Delay_semius(uint32_t Delay)
{__IO  uint32_t delayReg;uint32_t msNum = Delay/2000;uint32_t semiusNum = (uint32_t)((Delay%2000)*semiusDelayBase);if(msNum>0) HAL_Delay(msNum);delayReg = 0;while(delayReg!=semiusNum) delayReg++;
}
/* USER CODE END PTD *//* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD *//* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM *//* USER CODE END PM *//* Private variables ---------------------------------------------------------*/
TIM_HandleTypeDef htim2;/* USER CODE BEGIN PV */
#define TX_0 __HAL_TIM_SetCompare(&htim2, TIM_CHANNEL_3, 3)
#define TX_1 __HAL_TIM_SetCompare(&htim2, TIM_CHANNEL_3, 12)
#define TX_RST __HAL_TIM_SetCompare(&htim2, TIM_CHANNEL_3, 0)void PY_RGB_TX_Init(void)
{__HAL_TIM_SetCounter(&htim2, 0);TX_RST;HAL_TIM_PWM_Start(&htim2,TIM_CHANNEL_3);PY_Delay_semius_t(600);
}#define timing_delay {ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;ns_delay >>= 1;}
void PY_RGB_TX_24bits(uint8_t R, uint8_t G, uint8_t B) //Written by Pegasus Yu in 2022
{ //Data transmit in order of GRB, high bit data at first__IO uint32_t ns_delay = 0x55555555;__HAL_TIM_SetCounter(&htim2, 0);if((G<<0)&0x80) TX_1;else TX_0;timing_delayif((G<<1)&0x80) TX_1;else TX_0;timing_delayif((G<<2)&0x80) TX_1;else TX_0;timing_delayif((G<<3)&0x80) TX_1;else TX_0;timing_delayif((G<<4)&0x80) TX_1;else TX_0;timing_delayif((G<<5)&0x80) TX_1;else TX_0;timing_delayif((G<<6)&0x80) TX_1;else TX_0;timing_delayif((G<<7)&0x80) TX_1;else TX_0;timing_delayif((R<<0)&0x80) TX_1;else TX_0;timing_delayif((R<<1)&0x80) TX_1;else TX_0;timing_delayif((R<<2)&0x80) TX_1;else TX_0;timing_delayif((R<<3)&0x80) TX_1;else TX_0;timing_delayif((R<<4)&0x80) TX_1;else TX_0;timing_delayif((R<<5)&0x80) TX_1;else TX_0;timing_delayif((R<<6)&0x80) TX_1;else TX_0;timing_delayif((R<<7)&0x80) TX_1;else TX_0;timing_delayif((B<<0)&0x80) TX_1;else TX_0;timing_delayif((B<<1)&0x80) TX_1;else TX_0;timing_delayif((B<<2)&0x80) TX_1;else TX_0;timing_delayif((B<<3)&0x80) TX_1;else TX_0;timing_delayif((B<<4)&0x80) TX_1;else TX_0;timing_delayif((B<<5)&0x80) TX_1;else TX_0;timing_delayif((B<<6)&0x80) TX_1;else TX_0;timing_delayif((B<<7)&0x80) TX_1;else TX_0;PY_Delay_semius_t(1);TX_RST;PY_Delay_semius_t(600);}
/* USER CODE END PV *//* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_TIM2_Init(void);
/* USER CODE BEGIN PFP *//* USER CODE END PFP *//* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 *//* USER CODE END 0 *//*** @brief  The application entry point.* @retval int*/
int main(void)
{/* USER CODE BEGIN 1 *//* USER CODE END 1 *//* MCU Configuration--------------------------------------------------------*//* Reset of all peripherals, Initializes the Flash interface and the Systick. */HAL_Init();/* USER CODE BEGIN Init *//* USER CODE END Init *//* Configure the system clock */SystemClock_Config();/* USER CODE BEGIN SysInit *//* USER CODE END SysInit *//* Initialize all configured peripherals */MX_GPIO_Init();MX_TIM2_Init();/* USER CODE BEGIN 2 */PY_semiusDelayTest();PY_semiusDelayOptimize();PY_RGB_TX_Init();/* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){PY_RGB_TX_24bits(255, 0, 0);PY_Delay_semius_t(4000000);PY_RGB_TX_24bits(0, 255, 0);PY_Delay_semius_t(4000000);PY_RGB_TX_24bits(0, 0, 255);PY_Delay_semius_t(4000000);PY_RGB_TX_24bits(127, 0, 127);PY_Delay_semius_t(4000000);/* USER CODE END WHILE *//* USER CODE BEGIN 3 */}/* USER CODE END 3 */
}/*** @brief System Clock Configuration* @retval None*/
void SystemClock_Config(void)
{RCC_OscInitTypeDef RCC_OscInitStruct = {0};RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};/** Initializes the RCC Oscillators according to the specified parameters* in the RCC_OscInitTypeDef structure.*/RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;RCC_OscInitStruct.HSEState = RCC_HSE_ON;RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;RCC_OscInitStruct.HSIState = RCC_HSI_ON;RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK){Error_Handler();}/** Initializes the CPU, AHB and APB buses clocks*/RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK){Error_Handler();}
}/*** @brief TIM2 Initialization Function* @param None* @retval None*/
static void MX_TIM2_Init(void)
{/* USER CODE BEGIN TIM2_Init 0 *//* USER CODE END TIM2_Init 0 */TIM_ClockConfigTypeDef sClockSourceConfig = {0};TIM_MasterConfigTypeDef sMasterConfig = {0};TIM_OC_InitTypeDef sConfigOC = {0};/* USER CODE BEGIN TIM2_Init 1 *//* USER CODE END TIM2_Init 1 */htim2.Instance = TIM2;htim2.Init.Prescaler = 8;htim2.Init.CounterMode = TIM_COUNTERMODE_UP;htim2.Init.Period = 14;htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;if (HAL_TIM_Base_Init(&htim2) != HAL_OK){Error_Handler();}sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK){Error_Handler();}if (HAL_TIM_PWM_Init(&htim2) != HAL_OK){Error_Handler();}sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK){Error_Handler();}sConfigOC.OCMode = TIM_OCMODE_PWM1;sConfigOC.Pulse = 3;sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;sConfigOC.OCFastMode = TIM_OCFAST_ENABLE;if (HAL_TIM_PWM_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_3) != HAL_OK){Error_Handler();}/* USER CODE BEGIN TIM2_Init 2 *//* USER CODE END TIM2_Init 2 */HAL_TIM_MspPostInit(&htim2);}/*** @brief GPIO Initialization Function* @param None* @retval None*/
static void MX_GPIO_Init(void)
{/* GPIO Ports Clock Enable */__HAL_RCC_GPIOD_CLK_ENABLE();__HAL_RCC_GPIOB_CLK_ENABLE();}/* USER CODE BEGIN 4 *//* USER CODE END 4 *//*** @brief  This function is executed in case of error occurrence.* @retval None*/
void Error_Handler(void)
{/* USER CODE BEGIN Error_Handler_Debug *//* User can add his own implementation to report the HAL error return state */__disable_irq();while (1){}/* USER CODE END Error_Handler_Debug */
}#ifdef  USE_FULL_ASSERT
/*** @brief  Reports the name of the source file and the source line number*         where the assert_param error has occurred.* @param  file: pointer to the source file name* @param  line: assert_param error line source number* @retval None*/
void assert_failed(uint8_t *file, uint32_t line)
{/* USER CODE BEGIN 6 *//* User can add his own implementation to report the file name and line number,ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) *//* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

注意MCU在不同主频下，#define timing_delay 后的 ns_delay >>= 1; 数量应做适应性调整以满足纳秒级时序要求。

STM32工程测试效果

上述代码实现4个延时的循环显示（包括典型的红色，绿色，蓝色），时序波形测试及颜色显示效果如下：

例程下载

STM32F103C6T6驱动W2812例程

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