0

这是我使用 DMA 的 DAC 代码。我想生成频率为 8kHz 的三角波，DAC 以 1MSPS 的更新速率运行。我正在使用 CUBEMX 和系统工作台。我正在为 DAC 使用定时器触发器。我正在研究 stm32L476 发现板。当我尝试将更新速率设置为 1MSPS 时，我没有收到任何通知。当我将更新速率设置为 500ksps 时，会得到斜率不均匀的三角波。谁能告诉我我应该怎么做才能解决这个问题以及我应该怎么做才能让我的代码按需要运行？

#include "main.h"
#include "stm32l4xx_hal.h"
/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* Private variables -------------------------------------------------------
--*/
DAC_HandleTypeDef hdac1;
DMA_HandleTypeDef hdma_dac_ch2;

TIM_HandleTypeDef htim2;

/* USER CODE BEGIN PV */
/* Private variables -------------------------------------------------------
--*/

/* 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_DAC1_Init(void);
static void MX_TIM2_Init(void);

/* USER CODE BEGIN PFP */
/* Private function prototypes ---------------------------------------------
--*/
const uint16_t val[] = {65,130,195,260,325,390,455,520,
    585,650,715,780,846,911,976,1041,
    1106,1171,1236,1301,1366,1431,1496,1561,
    1626,1691,1756,1821,1886,1951,2016,2081,
    2146,2211,2276,2341,2406,2472,2537,2602,
    2667,2732,2797,2862,2927,2992,3057,3122,
    3187,3252,3317,3382,3447,3512,3577,3642,
    3707,3772,3837,3902,3967,4032,4065,4032,
    3967,3902,3837,3772,3707,3642,3577,3512,
    3447,3382,3317,3252,3187,3122,3057,2992,
    2927,2862,2797,2732,2667,2602,2537,2472,
    2406,2341,2276,2211,2146,2081,2016,1951,
    1886,1821,1756,1691,1626,1561,1496,1431,
    1366,1301,1236,1171,1106,1041,976,911,
    846,780,715,650,585,520,455,390,
    325,260,195,130,65,0};
/* USER CODE BEGIN 0 */
/* USER CODE END PFP */

/* USER CODE BEGIN 0 */
/* USER CODE END PFP */

/* USER CODE BEGIN 0 */
/* USER CODE END PFP */

/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

int main(void)
    {

  /* USER CODE BEGIN 1 */
    int n=sizeof(val);
    int l=n/sizeof(val[0]);
    /* 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_DMA_Init();
  MX_DAC1_Init();
  MX_TIM2_Init();

   /* USER CODE BEGIN 2 */
   HAL_TIM_Base_Start(&htim2);
   //HAL_DAC_Start(&hdac1, DAC_CHANNEL_2);
   HAL_DAC_Start_DMA(&hdac1, DAC_CHANNEL_2, (uint32_t*)val, l,                DAC_ALIGN_12B_R);
   /* USER CODE END 2 */

   /* Infinite loop */
   /* USER CODE BEGIN WHILE */
   while (1)
   {
   /* USER CODE END WHILE */

   /* USER CODE BEGIN 3 */

   }
   /* USER CODE END 3 */

 }

 /** System Clock Configuration
 */
 void SystemClock_Config(void)
 {

   RCC_OscInitTypeDef RCC_OscInitStruct;
   RCC_ClkInitTypeDef RCC_ClkInitStruct;

     /**Initializes the CPU, AHB and APB busses clocks 
     */
   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
   RCC_OscInitStruct.MSIState = RCC_MSI_ON;
   RCC_OscInitStruct.MSICalibrationValue = 0;
   RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_6;
   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_MSI;
   RCC_OscInitStruct.PLL.PLLM = 1;
   RCC_OscInitStruct.PLL.PLLN = 40;
   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV7;
  RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;
   RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;
   if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
   {
     _Error_Handler(__FILE__, __LINE__);
   }

     /**Initializes the CPU, AHB and APB busses 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_DIV4;
   RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV4;

   if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK)
   {
     _Error_Handler(__FILE__, __LINE__);
   }

     /**Configure the main internal regulator output voltage 
     */
   if (HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1) !=      HAL_OK)
   {
     _Error_Handler(__FILE__, __LINE__);
   }

     /**Configure the Systick interrupt time 
     */
   HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);

     /**Configure the Systick 
     */
   HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);

   /* SysTick_IRQn interrupt configuration */
   HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);
 }

 /* DAC1 init function */
 static void MX_DAC1_Init(void)
 {

   DAC_ChannelConfTypeDef sConfig;

     /**DAC Initialization 
     */
   hdac1.Instance = DAC1;
   if (HAL_DAC_Init(&hdac1) != HAL_OK)
   {
     _Error_Handler(__FILE__, __LINE__);
   }

     /**DAC channel OUT2 config 
     */
   sConfig.DAC_SampleAndHold = DAC_SAMPLEANDHOLD_DISABLE;
   sConfig.DAC_Trigger = DAC_TRIGGER_T2_TRGO;
   sConfig.DAC_OutputBuffer = DAC_OUTPUTBUFFER_ENABLE;
   sConfig.DAC_ConnectOnChipPeripheral = DAC_CHIPCONNECT_ENABLE;
   sConfig.DAC_UserTrimming = DAC_TRIMMING_FACTORY;
   if (HAL_DAC_ConfigChannel(&hdac1, &sConfig, DAC_CHANNEL_2) != HAL_OK)
   {
     _Error_Handler(__FILE__, __LINE__);
   }

 }

 /* TIM2 init function */
 static void MX_TIM2_Init(void)
 {

   TIM_ClockConfigTypeDef sClockSourceConfig;
   TIM_MasterConfigTypeDef sMasterConfig;

   htim2.Instance = TIM2;
   htim2.Init.Prescaler = 19;
   htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
   htim2.Init.Period = 1;
   htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
   if (HAL_TIM_Base_Init(&htim2) != HAL_OK)
   {
     _Error_Handler(__FILE__, __LINE__);
   }

   sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
   if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK)
   {
     _Error_Handler(__FILE__, __LINE__);
   }

   sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
   sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
   if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) !=      HAL_OK)
   {
     _Error_Handler(__FILE__, __LINE__);
   }

 }

 /** 
   * Enable DMA controller clock
        */
 static void MX_DMA_Init(void) 
 {
   /* DMA controller clock enable */
   __HAL_RCC_DMA1_CLK_ENABLE();

        /* DMA interrupt init */
   /* DMA1_Channel4_IRQn interrupt configuration */
        HAL_NVIC_SetPriority(DMA1_Channel4_IRQn, 0, 0);
   HAL_NVIC_EnableIRQ(DMA1_Channel4_IRQn);

 }

 /** Configure pins as 
         * Analog 
              * Input 
              * Output
         * EVENT_OUT
         * EXTI
 */
 static void MX_GPIO_Init(void)
 {

   GPIO_InitTypeDef GPIO_InitStruct;

   /* GPIO Ports Clock Enable */
        __HAL_RCC_GPIOA_CLK_ENABLE();

   /*Configure GPIO pin : PA4 */
   GPIO_InitStruct.Pin = GPIO_PIN_4;
   GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
   GPIO_InitStruct.Pull = GPIO_NOPULL;
   HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

 }

 /* USER CODE BEGIN 4 */

 /* USER CODE END 4 */

 /**
        * @brief  This function is executed in case of error occurrence.
   * @param  None
   * @retval None
   */
      void _Error_Handler(char * file, int line)
 {
   /* USER CODE BEGIN Error_Handler_Debug */
   /* User can add his own implementation to report the HAL error return      state */
   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
4

2 回答 2

0

它是 STM32 的版本，带有 DMA 通道和一个带有两个通道的 DAC。易于修改为您的微

void StartDAC(DAC_TypeDef *dac, int DACchannel, uint16_t Nsamples, uint16_t *samples, uint16_t psc, uint16_t arr)
{

    DMA_Channel_TypeDef *DMA_Channel = !DACchannel ? DMA2_Channel3 : DMA2_Channel4;
    TIM_TypeDef *tim = !DACchannel ? TIM6 : TIM7;

    DMA_Channel->CCR = 0;
    if (!DACchannel)
    {
        dac->CR &= ~(DAC_CR_DMAUDRIE1 | DAC_CR_DMAEN1);
        dac->CR |= (DAC_CR_DMAUDRIE1 | DAC_CR_DMAEN1);
    }
    else
    {
        dac->CR &= ~(DAC_CR_DMAUDRIE2 | DAC_CR_DMAEN2);
        dac->CR |= (DAC_CR_DMAUDRIE2 | DAC_CR_DMAEN2);
    }
    DMA_Channel->CNDTR = Nsamples;
    DMA_Channel->CMAR = (uint32_t)samples;
    DMA_Channel->CPAR = !(DACchannel) ? (uint32_t)&DAC->DHR12R1 : (uint32_t)&DAC->DHR12R2;
    DMA_Channel->CCR |= DMA_CCR_MSIZE_0 | DMA_CCR_PSIZE_0 | DMA_CCR_MINC | DMA_CCR_CIRC | DMA_CCR_EN | DMA_CCR_TEIE | DMA_CCR_DIR;
    tim->DIER = TIM_DIER_UDE;// | TIM_DIER_UIE;
    tim->CR2 |= TIM_CR2_MMS_1;
    tim->PSC = psc;
    tim->ARR = arr;
    /* tim clock frequency / ((psc + 1) * (arr + 1) * nsamples)  == frequency of the  generated signal    - do the calculations yourself*/
    tim->CR1 |= TIM_CR1_CEN;
}
于 2017-10-24T11:17:19.233 回答
0

好吧，我刚刚弄清楚问题出在哪里。当 DAC 与外部输出引脚一起连接到其他外设时，它的速度会受到限制。要以更高的速度使用 DAC，DAC 应仅连接到外部引脚。至少这是我发现的。以前，我选择了将 DAC 连接到外部引脚和片上外围设备的选项。所以我不能高速使用DAC。但是后来我选择了仅外部引脚的选项（DAC 仅连接到外部引脚），它解决了问题并且 DAC 工作得很好。还要确保没有与该 DAC 输出引脚串联的电阻电容电路，否则输出波可能会受到干扰。

于 2017-11-10T10:55:43.747 回答