关于STM32F4xx使用DMA+TIM3_PWM调试灯带WS2812过程记录
1、叙述
（1）叙述
最近调试灯带2812，尝试使用PA6引脚调试，以前没怎么用过，通过不断找资料学习，成功点亮灯带，但是这其中还是踩了不少坑，这个过程，以及过程中遇到的问题值得记录下来，引以为鉴。
（2）环境
MCU:STM32F407ZGT6
开发工具：STM32CubeIDE 1.7.0
HAL库版本：stm32cube_fw_f4_v1262
2、参考文档
本文主要参考以下文档，写的言简意赅，并且有相关配置，这里就不重复了。
DMA+PWM形式：
https://blog.csdn.net/qq_17351161/article/details/107285588#comments_12806183
DMA+PWM形式（双缓冲模式）：
https://blog.csdn.net/qq_17351161/article/details/107346568
自我实现
实现代码
通过学习上述文字内容，自己用软件STM32CubeIDE重新，在F1和F4上都实现了一边，这里给实现的四个代码，需要的自行下载，都是STM32CubeIDE版本，共四种。
STM32F1上DMA+PWM形式（TIM2 ）：
https://download.csdn.net/download/qq_22146161/54793933
STM32F1上DMA+PWM形式（TIM2 TIM3双缓冲）：
https://download.csdn.net/download/qq_22146161/54794408
STM32F4上DMA+PWM形式（TIM3 ch1 ch2）PA6 PA7：
https://download.csdn.net/download/qq_22146161/58667099
STM32F4上DMA+PWM形式（TIM3 h1 ch2双缓冲）PA6 PA7：
https://download.csdn.net/download/qq_22146161/54824864
代码细节
以上述代码第三为例，也就是“STM32F4上DMA+PWM形式（TIM3 ch1 ch2）PA6 PA7”为例，代码包括三个主要部分
初始配置
代码在软件 STM32CubeIDE 配置完成后一部分会在文件“stm32f4xx_hal_msp.c”这部分包括PWM配置和端口引脚配置。
其中>>void HAL_TIM_PWM_MspInit(TIM_HandleTypeDef* htim_pwm);
和函数>>void HAL_TIM_MspPostInit(TIM_HandleTypeDef* htim);非常重要
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file stm32f4xx_hal_msp.c
* @brief This file provides code for the MSP Initialization
* and de-Initialization codes.
******************************************************************************
* @attention
*
* <h2><center>© Copyright (c) 2021 STMicroelectronics.
* All rights reserved.</center></h2>
*
* This software component is licensed by ST under BSD 3-Clause license,
* the "License"; You may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
* opensource.org/licenses/BSD-3-Clause
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
/* USER CODE BEGIN Includes */
/* USER CODE END Includes */
extern DMA_HandleTypeDef hdma_tim3_ch2;
extern DMA_HandleTypeDef hdma_tim3_ch1_trig;
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN TD */
/* USER CODE END TD */
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN Define */
/* USER CODE END Define */
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN Macro */
/* USER CODE END Macro */
/* Private variables ---------------------------------------------------------*/
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* External functions --------------------------------------------------------*/
/* USER CODE BEGIN ExternalFunctions */
/* USER CODE END ExternalFunctions */
/* USER CODE BEGIN 0 */
/* USER CODE END 0 */
void HAL_TIM_MspPostInit(TIM_HandleTypeDef *htim);
/**
* Initializes the Global MSP.
*/
void HAL_MspInit(void)
{
/* USER CODE BEGIN MspInit 0 */
/* USER CODE END MspInit 0 */
__HAL_RCC_SYSCFG_CLK_ENABLE();
__HAL_RCC_PWR_CLK_ENABLE();
/* System interrupt init*/
/* USER CODE BEGIN MspInit 1 */
/* USER CODE END MspInit 1 */
}
/**
* @brief TIM_PWM MSP Initialization
* This function configures the hardware resources used in this example
* @param htim_pwm: TIM_PWM handle pointer
* @retval None
*/
void HAL_TIM_PWM_MspInit(TIM_HandleTypeDef* htim_pwm)
{
if(htim_pwm->Instance==TIM3)
{
/* USER CODE BEGIN TIM3_MspInit 0 */
/* USER CODE END TIM3_MspInit 0 */
/* Peripheral clock enable */
__HAL_RCC_TIM3_CLK_ENABLE();
/* TIM3 DMA Init */
/* TIM3_CH2 Init */
hdma_tim3_ch2.Instance = DMA1_Stream5;
hdma_tim3_ch2.Init.Channel = DMA_CHANNEL_5;
hdma_tim3_ch2.Init.Direction = DMA_MEMORY_TO_PERIPH;
hdma_tim3_ch2.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_tim3_ch2.Init.MemInc = DMA_MINC_ENABLE;
hdma_tim3_ch2.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
hdma_tim3_ch2.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
hdma_tim3_ch2.Init.Mode = DMA_CIRCULAR;
hdma_tim3_ch2.Init.Priority = DMA_PRIORITY_VERY_HIGH;
hdma_tim3_ch2.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
if (HAL_DMA_Init(&hdma_tim3_ch2) != HAL_OK)
{
Error_Handler();
}
__HAL_LINKDMA(htim_pwm,hdma[TIM_DMA_ID_CC2],hdma_tim3_ch2);
/* TIM3_CH1_TRIG Init */
hdma_tim3_ch1_trig.Instance = DMA1_Stream4;
hdma_tim3_ch1_trig.Init.Channel = DMA_CHANNEL_5;
hdma_tim3_ch1_trig.Init.Direction = DMA_MEMORY_TO_PERIPH;
hdma_tim3_ch1_trig.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_tim3_ch1_trig.Init.MemInc = DMA_MINC_ENABLE;
hdma_tim3_ch1_trig.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
hdma_tim3_ch1_trig.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
hdma_tim3_ch1_trig.Init.Mode = DMA_CIRCULAR;
hdma_tim3_ch1_trig.Init.Priority = DMA_PRIORITY_VERY_HIGH;
hdma_tim3_ch1_trig.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
if (HAL_DMA_Init(&hdma_tim3_ch1_trig) != HAL_OK)
{
Error_Handler();
}
/* Several peripheral DMA handle pointers point to the same DMA handle.
Be aware that there is only one stream to perform all the requested DMAs. */
__HAL_LINKDMA(htim_pwm,hdma[TIM_DMA_ID_CC1],hdma_tim3_ch1_trig);
__HAL_LINKDMA(htim_pwm,hdma[TIM_DMA_ID_TRIGGER],hdma_tim3_ch1_trig);
/* USER CODE BEGIN TIM3_MspInit 1 */
/* USER CODE END TIM3_MspInit 1 */
}
}
void HAL_TIM_MspPostInit(TIM_HandleTypeDef* htim)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
if(htim->Instance==TIM3)
{
/* USER CODE BEGIN TIM3_MspPostInit 0 */
/* USER CODE END TIM3_MspPostInit 0 */
__HAL_RCC_GPIOA_CLK_ENABLE();
/**TIM3 GPIO Configuration
PA6 ------> TIM3_CH1
PA7 ------> TIM3_CH2
*/
GPIO_InitStruct.Pin = GPIO_PIN_6|GPIO_PIN_7;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF2_TIM3;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* USER CODE BEGIN TIM3_MspPostInit 1 */
/* USER CODE END TIM3_MspPostInit 1 */
}
}
/**
* @brief TIM_PWM MSP De-Initialization
* This function freeze the hardware resources used in this example
* @param htim_pwm: TIM_PWM handle pointer
* @retval None
*/
void HAL_TIM_PWM_MspDeInit(TIM_HandleTypeDef* htim_pwm)
{
if(htim_pwm->Instance==TIM3)
{
/* USER CODE BEGIN TIM3_MspDeInit 0 */
/* USER CODE END TIM3_MspDeInit 0 */
/* Peripheral clock disable */
__HAL_RCC_TIM3_CLK_DISABLE();
/* TIM3 DMA DeInit */
HAL_DMA_DeInit(htim_pwm->hdma[TIM_DMA_ID_CC2]);
HAL_DMA_DeInit(htim_pwm->hdma[TIM_DMA_ID_CC1]);
HAL_DMA_DeInit(htim_pwm->hdma[TIM_DMA_ID_TRIGGER]);
/* USER CODE BEGIN TIM3_MspDeInit 1 */
/* USER CODE END TIM3_MspDeInit 1 */
}
}
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
功能代码实现
功能部分代码主要参考博客文章里，另外这里定时器初始化也需要注意
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* <h2><center>© Copyright (c) 2021 STMicroelectronics.
* All rights reserved.</center></h2>
*
* This software component is licensed by ST under BSD 3-Clause license,
* the "License"; You may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
* opensource.org/licenses/BSD-3-Clause
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
/* USER CODE END Includes */
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
/* 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 htim3;
DMA_HandleTypeDef hdma_tim3_ch2;
DMA_HandleTypeDef hdma_tim3_ch1_trig;
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_TIM3_Init(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
#define ONE_PULSE (59) //1 ????êy??êy
#define ZERO_PULSE (29) //0 ????êy??êy
#define RESET_PULSE (48) //80 ?′??μ?????êy￡¨2??üμíóú40￡?
#define LED_NUMS (4) //led ??êy
#define LED_DATA_LEN (24) //led 3¤?è￡?μ￥??Dèòa24??×??ú
#define WS2812_DATA_LEN (LED_NUMS*LED_DATA_LEN) //ws2812μ?ì?Dèòaμ?êy×é3¤?è
uint16_t static RGB_buffur[RESET_PULSE + WS2812_DATA_LEN] = { 0 };
void ws2812_set_RGB(uint8_t R, uint8_t G, uint8_t B, uint16_t num)
{
//??????ò?:Dèòaì?1y?′??D?o?μ?N??0
uint16_t* p = (RGB_buffur + RESET_PULSE) + (num * LED_DATA_LEN);
for (uint16_t i = 0;i < 8;i++)
{
//ì?3?êy×é
p[i] = (G << i) & (0x80)?ONE_PULSE:ZERO_PULSE;
p[i + 8] = (R << i) & (0x80)?ONE_PULSE:ZERO_PULSE;
p[i + 16] = (B << i) & (0x80)?ONE_PULSE:ZERO_PULSE;
}
}
void HAL_TIM_PWM_PulseFinishedCallback(TIM_HandleTypeDef *htim)
{
__HAL_TIM_SetCompare(htim, TIM_CHANNEL_1,0); //占空比清0，若不清会导致灯珠颜色不对
HAL_TIM_PWM_Stop_DMA(htim,TIM_CHANNEL_1);
__HAL_TIM_SetCompare(htim, TIM_CHANNEL_2,0); //占空比清0，若不清会导致灯珠颜色不对
HAL_TIM_PWM_Stop_DMA(htim,TIM_CHANNEL_2);
}
void ws2812_example(void)
{
/*
ws2812_set_RGB(0x22, 0x00, 0x00, 0);
ws2812_set_RGB(0x00, 0x22, 0x00, 1);
ws2812_set_RGB(0x00, 0x00, 0x22, 2);
ws2812_set_RGB(0x22, 0x22, 0x22, 3);
HAL_TIM_PWM_Start_DMA(&htim3,TIM_CHANNEL_1,(uint32_t *)RGB_buffur,176);
HAL_TIM_PWM_Start_DMA(&htim3,TIM_CHANNEL_2,(uint32_t *)RGB_buffur,176);
HAL_Delay(500);
*/
///R-红///G-绿//B-蓝/第几个灯//
ws2812_set_RGB(0x22, 0x22, 0x22, 0); //0010 0010 0010 0010 0010 0010
ws2812_set_RGB(0x22, 0x00, 0x00, 1); //0010 0010 0000 0000 0000 0000
ws2812_set_RGB(0x00, 0x22, 0x00, 2); //0000 0000 0010 0010 0000 0000
ws2812_set_RGB(0x00, 0x00, 0x22, 3); //0000 0010 0000 0000 0010 0010
//发送
HAL_TIM_PWM_Start_DMA(&htim3,TIM_CHANNEL_1,(uint32_t *)RGB_buffur,176);
HAL_TIM_PWM_Start_DMA(&htim3,TIM_CHANNEL_2,(uint32_t *)RGB_buffur,176);
HAL_Delay(500);
}
/* 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_TIM3_Init();
MX_DMA_Init();
MX_TIM3_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
ws2812_example();
/* 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};
/** Configure the main internal regulator output voltage
*/
__HAL_RCC_PWR_CLK_ENABLE();
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
/** 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.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLM = 4;
RCC_OscInitStruct.PLL.PLLN = 168;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
RCC_OscInitStruct.PLL.PLLQ = 4;
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_DIV2;
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 TIM3 Initialization Function
* @param None
* @retval None
*/
static void MX_TIM3_Init(void)
{
/* USER CODE BEGIN TIM3_Init 0 */
/* USER CODE END TIM3_Init 0 */
TIM_MasterConfigTypeDef sMasterConfig = {0};
TIM_OC_InitTypeDef sConfigOC = {0};
/* USER CODE BEGIN TIM3_Init 1 */
/* USER CODE END TIM3_Init 1 */
htim3.Instance = TIM3;
htim3.Init.Prescaler = 0;
htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
htim3.Init.Period = 105;
htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
// htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_PWM_Init(&htim3) != HAL_OK)
{
Error_Handler();
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
sConfigOC.OCMode = TIM_OCMODE_PWM1;
sConfigOC.Pulse = 74;
sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
if (HAL_TIM_PWM_ConfigChannel(&htim3, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
{
Error_Handler();
}
if (HAL_TIM_PWM_ConfigChannel(&htim3, &sConfigOC, TIM_CHANNEL_2) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN TIM3_Init 2 */
/* USER CODE END TIM3_Init 2 */
HAL_TIM_MspPostInit(&htim3);
}
/**
* Enable DMA controller clock
*/
static void MX_DMA_Init(void)
{
/* DMA controller clock enable */
__HAL_RCC_DMA1_CLK_ENABLE();
/* DMA interrupt init */
/* DMA1_Stream4_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA1_Stream4_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA1_Stream4_IRQn);
/* DMA1_Stream5_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA1_Stream5_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA1_Stream5_IRQn);
}
/**
* @brief GPIO Initialization Function
* @param None
* @retval None
*/
static void MX_GPIO_Init(void)
{
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOH_CLK_ENABLE();
__HAL_RCC_GPIOA_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 */
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
3、验证
如下图，是灯带效果图
还有示波器抓到的波形图
4、在F4上遇到的问题
如果细心的小伙伴们可能也注意到了
F4上没有使用TIM2,多次尝试到发文为止，还未解决，并挂在网上悬赏，链接如下，描述很清楚了。
https://ask.csdn.net/questions/7589282
5、调试细节-问题记录
（1）初始化顺序
在主函数内初始化顺序不要改变
在主函数内初始化顺序不要改变
在主函数内初始化顺序不要改变
重要的事情说三遍，在尝试移植的过程中，发现波形突然不受控制了。
DMA无法输出正常波形。
后来发现移植时候，虽然代码像下边那样些，但是实际上，在别处定时器3先初始化了，移植时很难找到这个毛病。
推导出代码顺序非常重要，有时候发现明明好好的代码在移植时，或者突然出问题，可能需要检查顺序。
MX_GPIO_Init();
// MX_TIM3_Init();
MX_DMA_Init();
MX_TIM3_Init();
（2）上下拉问题
在F4中，PA6和PA7默认上下是不同的，PA6默认下拉，PA7默认上拉
可以在代码 GPIO_InitStruct.Pull = GPIO_PULLDOWN;更改为下拉，或者每个引脚单独设置。
void HAL_TIM_MspPostInit(TIM_HandleTypeDef* htim)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
if(htim->Instance==TIM3)
{
/* USER CODE BEGIN TIM3_MspPostInit 0 */
/* USER CODE END TIM3_MspPostInit 0 */
__HAL_RCC_GPIOA_CLK_ENABLE();
/**TIM3 GPIO Configuration
PA6 ------> TIM3_CH1
PA7 ------> TIM3_CH2
*/
GPIO_InitStruct.Pin = GPIO_PIN_6|GPIO_PIN_7;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_PULLDOWN;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF2_TIM3;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* USER CODE BEGIN TIM3_MspPostInit 1 */
/* USER CODE END TIM3_MspPostInit 1 */
}
（3）验证2-后期逻辑仪抓取波形
后来上逻辑分析仪，那么可以通过抓取波形来验证输入代码对不对了，功能代码如下图，注意ws2812_set_RGB函数后面设置的数组，理论上逻辑仪出来的也应该对应，即ws2812这个灯珠以1.25us为一个周期，1/3方波认为是0，2/3方波认为是1。
这里一共4个灯那么，如下图是抓出来的，可以看到数据是一致的，另外上下两个波形差了点位置，说明CPU代码执行先后是时间有间隔的。
6、总结
这次确实也学到不少东西，希望我的前车之鉴，对你们有参考价值，也是自我记录与总结。