STM32F407_HAL_TIM_DMA驱动WS2812

初始化函数可以通过CubeMX配置，这里直接通过原码记录：

注意点：

STM32F407配置时钟频率为168MHz,TIM3挂载再APB1总线上时钟频率为84MHz，WS2812B需要的时钟频率为800K则定时器预装载寄存器的初值应配置为84M/800K = 105

0码和1码的配置需要根据预装载寄存器设定的初值来配置以符合WS2812手册中的0码和1码的时序。可参考：https://blog.csdn.net/xiaoyuanwuhui/article/details/99639068

芯片外设层驱动

tim.h

#ifndef __TIM_H

#define __TIM_H

#include "stm32f4xx.h"

extern TIM_HandleTypeDef htim3;

void HAL_TIM_MspPostInit(TIM_HandleTypeDef* timHandle);

void tim3_init(void);

#endif /* __TIM_H */

tim.c

#include "tim.h"

TIM_HandleTypeDef htim3;

DMA_HandleTypeDef hdma_tim3_ch1_trig;

void tim3_init(void)

{

  TIM_MasterConfigTypeDef sMasterConfig;

  TIM_OC_InitTypeDef sConfigOC;

  htim3.Instance = TIM3;

  htim3.Init.Prescaler = 0;

  htim3.Init.CounterMode = TIM_COUNTERMODE_UP;

  htim3.Init.Period = 105-1;

  htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;

  if (HAL_TIM_PWM_Init(&htim3) != HAL_OK)

  {

    // _Error_Handler(__FILE__, __LINE__);

  }

  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;

  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;

  if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)

  {

    // _Error_Handler(__FILE__, __LINE__);

  }

  sConfigOC.OCMode = TIM_OCMODE_PWM1;

  sConfigOC.Pulse = 0;

  sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;

  sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;

  if (HAL_TIM_PWM_ConfigChannel(&htim3, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)

  {

    // _Error_Handler(__FILE__, __LINE__);

  }

  HAL_TIM_MspPostInit(&htim3);

}

void HAL_TIM_PWM_MspInit(TIM_HandleTypeDef* tim_pwmHandle)

{

  if(tim_pwmHandle->Instance==TIM3)

  {

    /* TIM3 clock enable */

    __HAL_RCC_TIM3_CLK_ENABLE();

    /* DMA controller clock enable */

    __HAL_RCC_DMA1_CLK_ENABLE();

    /* TIM3 DMA Init */

    /* 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_NORMAL;

    hdma_tim3_ch1_trig.Init.Priority = DMA_PRIORITY_MEDIUM;

    hdma_tim3_ch1_trig.Init.FIFOMode = DMA_FIFOMODE_DISABLE;

    if (HAL_DMA_Init(&hdma_tim3_ch1_trig) != HAL_OK)

    {

      // _Error_Handler(__FILE__, __LINE__);

    }

    /* 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(tim_pwmHandle,hdma[TIM_DMA_ID_CC1],hdma_tim3_ch1_trig);

    __HAL_LINKDMA(tim_pwmHandle,hdma[TIM_DMA_ID_TRIGGER],hdma_tim3_ch1_trig);

    /* TIM3 interrupt Init */

    HAL_NVIC_SetPriority(TIM3_IRQn, 0, 0);

    HAL_NVIC_EnableIRQ(TIM3_IRQn);

    /* DMA interrupt init */

    /* DMA1_Stream4_IRQn interrupt configuration */

    HAL_NVIC_SetPriority(DMA1_Stream4_IRQn, 0, 0);

    HAL_NVIC_EnableIRQ(DMA1_Stream4_IRQn);

  }

}

void HAL_TIM_MspPostInit(TIM_HandleTypeDef* timHandle)

{

  GPIO_InitTypeDef GPIO_InitStruct;

  if(timHandle->Instance==TIM3)

  {

    /* GPIOA clock enable */

    __HAL_RCC_GPIOA_CLK_ENABLE();

    /**TIM3 GPIO Configuration    

    PA6     ------> TIM3_CH1 

    */

    GPIO_InitStruct.Pin = GPIO_PIN_6;

    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);

  }

}

void HAL_TIM_PWM_MspDeInit(TIM_HandleTypeDef* tim_pwmHandle)

{

  if(tim_pwmHandle->Instance==TIM3)

  {

    /* Peripheral clock disable */

    __HAL_RCC_TIM3_CLK_DISABLE();

    /* TIM3 DMA DeInit */

    HAL_DMA_DeInit(tim_pwmHandle->hdma[TIM_DMA_ID_CC1]);

    HAL_DMA_DeInit(tim_pwmHandle->hdma[TIM_DMA_ID_TRIGGER]);

    /* TIM3 interrupt Deinit */

    HAL_NVIC_DisableIRQ(TIM3_IRQn);

  }

} 

/**

* @brief This function handles DMA1 stream4 global interrupt.

*/

void DMA1_Stream4_IRQHandler(void)

{

  HAL_DMA_IRQHandler(&hdma_tim3_ch1_trig);

}

/**

* @brief This function handles TIM3 global interrupt.

*/

void TIM3_IRQHandler(void)

{

  HAL_TIM_IRQHandler(&htim3);

}

WS2812硬件驱动

ws281x.h

#ifndef __WS281X_H

#define __WS281x_H

#include "tim.h"

void ws281x_init(void);

void ws281x_show(void);

uint32_t ws281x_color(uint8_t r, uint8_t g, uint8_t b);

void ws281x_setColor(uint16_t n, uint32_t color);

void ws281x_close(void);

#endif /* __WS281X_H */

ws281x.c

#include "WS281x.h"

#include

#ifndef PIXEL_NUM

  #define PIXEL_NUM 5

#endif

#define GRB (3*8)

#define WS_TERO 30

#define WS_ONE  45

/* pwm 占空比数值为uint16_t 类型，DMA传输时只能以半字输出，pixelBuffer应为uint16_t 类型 */

uint16_t pixelBuffer[PIXEL_NUM][GRB]; 

void ws281x_init(void)

{

  /* 配置TIM3 pwm频率为800Khz */

  tim3_init();

}

void ws281x_show(void)

{

  HAL_TIM_PWM_Start_DMA(&htim3, TIM_CHANNEL_1, (uint32_t *)pixelBuffer, PIXEL_NUM * GRB);

}

uint32_t ws281x_color(uint8_t r, uint8_t g, uint8_t b)

{

  return (uint32_t)(g << 16 | r << 8 | b);

}

/* pixel num from 0 start */

void ws281x_setColor(uint16_t n, uint32_t color)

{

  if(n < PIXEL_NUM)

  {

    for(uint8_t i = 0; i < GRB; ++i)

    {

      pixelBuffer[n][i] = ((color << i) & 0x800000) ? WS_ONE : WS_TERO;

    }

  }

}

void ws281x_close(void)

{

  uint16_t* ptr = (uint16_t *)pixelBuffer; 

  for(uint16_t i = 0; i < PIXEL_NUM * GRB; ++i)

  {

    *ptr++ = WS_TERO;

  }

  ws281x_show();

}

/* 中断回调函数，在设定的pwm通过DMA发送完成后会调用 */

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);

}

结语

这里只实现了底层驱动接口，未移植显示效果部分的代码，显示效果可参考我的其他WS2812相关文章。HAL库分层效果确实好，但内部代码的理解难度要高很多