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。我正在使用DAC的定时器触发器。 我正在研究stm32L476发现板。当我尝试将更新速率设置为1MSPS时，我没有得到任何波形。当我将更新速率设置为500ksps时，我得到具有不均匀斜率的三角波。任何人都可以告诉我应该怎么做才能解决这个问题，我该怎么做才能让我的代码按需运行？
#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
答案 0 :(得分：0)
这是带有DMA通道的STM32和带有两个通道的一个DAC的版本。很容易为你的micro推荐
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;
}
答案 1 :(得分：0)
我刚刚弄明白问题出在哪里。当DAC速度与外部输出引脚连接到其他外设时，DAC速度受到限制。要以更高的速度使用DAC，DAC应仅连接到外部引脚。至少那是我发现的。以前，我选择了将DAC连接到外部引脚和片上外设的选项。所以我无法高速使用DAC。但后来我选择了外部引脚选项（DAC仅连接到外部引脚），它解决了问题，DAC工作正常。还要确保没有与此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。