Controlling WS2812B LEDs with VLDISCOVERY (F100)

[PeterM1]

Hello,

I am in the process of writing some code to drive WS2812B Leds with PWM via DMA. Unfortunately there are usually three pulses too much.

Does anyone have an idea what this could be. Attached are a few excerpts from my program code. Thanks

main.c

int main(void) {
    HAL_Init();
    SystemClock_Config();
    MX_GPIO_Init();
    MX_DMA_Init();
    MX_TIM3_Init();
    while (1) {
        led_show();
        HAL_Delay(40);
    }
}

led.c

#include "stm32f1xx_hal.h"
extern TIM_HandleTypeDef htim3;
extern DMA_HandleTypeDef hdma_tim3_ch3;
 
#include "led.h"
 
#define PWM_HI 6
#define PWM_LO 3
 
uint8_t LED_BUF[50] = {0};
int dma_in_progress = 0;
 
void led_show() {
 
    if (dma_in_progress == 0) {
        LED_BUF[0] = PWM_LO;
        LED_BUF[1] = PWM_HI;
        LED_BUF[2] = PWM_LO;
        LED_BUF[3] = PWM_HI;
        LED_BUF[4] = PWM_LO;
        LED_BUF[5] = PWM_HI;
        LED_BUF[6] = PWM_LO;
        LED_BUF[7] = PWM_HI;
        LED_BUF[8] = PWM_LO;
        LED_BUF[9] = PWM_HI;
 
        dma_in_progress = 1;
 
        HAL_TIM_PWM_Start_DMA(&htim3, TIM_CHANNEL_3, (uint32_t *) LED_BUF, 50);
    }
}
 
void HAL_TIM_PWM_PulseFinishedCallback(TIM_HandleTypeDef *htim) {
    HAL_TIM_PWM_Stop(&htim3,TIM_CHANNEL_3);
    dma_in_progress = 0;
}

tim.c

#include "tim.h"
 
/* USER CODE BEGIN 0 */
 
/* USER CODE END 0 */
 
TIM_HandleTypeDef htim3;
DMA_HandleTypeDef hdma_tim3_ch3;
DMA_HandleTypeDef hdma_tim3_ch4_up;
 
/* TIM3 init function */
void MX_TIM3_Init(void)
{
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};
  TIM_OC_InitTypeDef sConfigOC = {0};
 
  htim3.Instance = TIM3;
  htim3.Init.Prescaler = 0;
  htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim3.Init.Period = 9;
  htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  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 = 0;
  sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
  sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
  if (HAL_TIM_PWM_ConfigChannel(&htim3, &sConfigOC, TIM_CHANNEL_3) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_TIM_PWM_ConfigChannel(&htim3, &sConfigOC, TIM_CHANNEL_4) != HAL_OK)
  {
    Error_Handler();
  }
  HAL_TIM_MspPostInit(&htim3);
 
}
 
void HAL_TIM_Base_MspInit(TIM_HandleTypeDef* tim_baseHandle)
{
 
  if(tim_baseHandle->Instance==TIM3)
  {
  /* USER CODE BEGIN TIM3_MspInit 0 */
 
  /* USER CODE END TIM3_MspInit 0 */
    /* TIM3 clock enable */
    __HAL_RCC_TIM3_CLK_ENABLE();
 
    /* TIM3 DMA Init */
    /* TIM3_CH3 Init */
    hdma_tim3_ch3.Instance = DMA1_Channel2;
    hdma_tim3_ch3.Init.Direction = DMA_MEMORY_TO_PERIPH;
    hdma_tim3_ch3.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_tim3_ch3.Init.MemInc = DMA_MINC_ENABLE;
    hdma_tim3_ch3.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;
    hdma_tim3_ch3.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_tim3_ch3.Init.Mode = DMA_NORMAL;
    hdma_tim3_ch3.Init.Priority = DMA_PRIORITY_LOW;
    if (HAL_DMA_Init(&hdma_tim3_ch3) != HAL_OK)
    {
      Error_Handler();
    }
 
    __HAL_LINKDMA(tim_baseHandle,hdma[TIM_DMA_ID_CC3],hdma_tim3_ch3);
 
    /* TIM3_CH4_UP Init */
    hdma_tim3_ch4_up.Instance = DMA1_Channel3;
    hdma_tim3_ch4_up.Init.Direction = DMA_MEMORY_TO_PERIPH;
    hdma_tim3_ch4_up.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_tim3_ch4_up.Init.MemInc = DMA_MINC_ENABLE;
    hdma_tim3_ch4_up.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;
    hdma_tim3_ch4_up.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_tim3_ch4_up.Init.Mode = DMA_CIRCULAR;
    hdma_tim3_ch4_up.Init.Priority = DMA_PRIORITY_LOW;
    if (HAL_DMA_Init(&hdma_tim3_ch4_up) != HAL_OK)
    {
      Error_Handler();
    }
 
    /* Several peripheral DMA handle pointers point to the same DMA handle.
     Be aware that there is only one channel to perform all the requested DMAs. */
    __HAL_LINKDMA(tim_baseHandle,hdma[TIM_DMA_ID_CC4],hdma_tim3_ch4_up);
    __HAL_LINKDMA(tim_baseHandle,hdma[TIM_DMA_ID_UPDATE],hdma_tim3_ch4_up);
 
  /* USER CODE BEGIN TIM3_MspInit 1 */
 
  /* USER CODE END TIM3_MspInit 1 */
  }
}
void HAL_TIM_MspPostInit(TIM_HandleTypeDef* timHandle)
{
 
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(timHandle->Instance==TIM3)
  {
  /* USER CODE BEGIN TIM3_MspPostInit 0 */
 
  /* USER CODE END TIM3_MspPostInit 0 */
 
    __HAL_RCC_GPIOB_CLK_ENABLE();
    /**TIM3 GPIO Configuration
    PB0     ------> TIM3_CH3
    PB1     ------> TIM3_CH4
    */
    GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
 
  /* USER CODE BEGIN TIM3_MspPostInit 1 */
 
  /* USER CODE END TIM3_MspPostInit 1 */
  }
 
}
 
void HAL_TIM_Base_MspDeInit(TIM_HandleTypeDef* tim_baseHandle)
{
 
  if(tim_baseHandle->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(tim_baseHandle->hdma[TIM_DMA_ID_CC3]);
    HAL_DMA_DeInit(tim_baseHandle->hdma[TIM_DMA_ID_CC4]);
    HAL_DMA_DeInit(tim_baseHandle->hdma[TIM_DMA_ID_UPDATE]);
  /* USER CODE BEGIN TIM3_MspDeInit 1 */
 
  /* USER CODE END TIM3_MspDeInit 1 */
  }
}
 
/* USER CODE BEGIN 1 */
 
/* USER CODE END 1 */
 
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