HAL_DMA_STATE_READY
时间: 2023-09-13 19:06:13 浏览: 95
HAL_DMA_STATE_READY是HAL库中的一个枚举类型,表示DMA初始化完毕并准备好进行数据传输的状态。 当DMA处于HAL_DMA_STATE_READY状态时,可以使用HAL库提供的函数进行数据传输操作,例如HAL_UART_Transmit_DMA函数用于以DMA模式发送数据。 在HAL库中,DMA的状态会在传输过程中进行改变,而当传输完成后会进入HAL_DMA_STATE_READY状态。要注意的是,如果连续使用HAL_UART_Transmit_DMA函数发送数据,相邻两次之间需要有延时或者检测DMA数据是否完成,以避免进入HAL_BUSY状态。 引用中给出了DMA的通道选项,可以根据需要选择合适的通道进行DMA传输操作。<span class="em">1</span><span class="em">2</span><span class="em">3</span><span class="em">4</span>
相关问题
HAL_UART_Transmit_DMA 显示HAL_UART_STATE_BUSY_TX
当调用HAL_UART_Transmit_DMA函数时,gState会被更改为HAL_UART_STATE_BUSY_TX状态,表示串口正在发送数据。 这个状态位会一直保持为HAL_UART_STATE_BUSY_TX,直到发送完成。 为了搞清楚gState保持不动的原因,我查看了代码并了解了状态位的重置机制。当执行HAL_UART_Transmit_DMA函数时,gState会被更改为HAL_UART_STATE_BUSY_TX状态。发送成功后,将触发串口中断,执行USART1_IRQHandler函数,然后再调用HAL_UART_IRQHandler函数。在HAL_UART_IRQHandler函数中,会调用UART_EndTransmit_IT函数,并在此函数中将标志位gState重置为HAL_UART_STATE_READY。只有在gState被重置为HAL_UART_STATE_READY的基础上,DMA发送函数HAL_UART_Transmit_DMA才能继续执行。 因此,如果在发送过程中gState保持为HAL_UART_STATE_BUSY_TX,那么HAL_UART_Transmit_DMA函数将无法连续运行。<span class="em">1</span><span class="em">2</span><span class="em">3</span><span class="em">4</span>
HAL_Transmit_DMA如何使用
HAL_Transmit_DMA()函数是HAL库中用于启动DMA传输的函数。使用该函数可以将数据从内存传输到外设,而无需CPU的干预。下面是使用HAL_Transmit_DMA()函数的步骤:
1.在代码中包含相应的头文件,例如:#include "stm32f4xx_hal.h"。
2.定义DMA_HandleTypeDef结构体变量,例如:DMA_HandleTypeDef hdma_usart1_tx;。
3.在HAL_UART_Transmit_DMA()函数前加上 extern DMA_HandleTypeDef hdma_usart1_tx;,以便在函数中使用hdma_usart1_tx变量。
4.在main()函数中初始化hdma_usart1_tx变量,例如:hdma_usart1_tx.Instance = DMA2_Stream7; hdma_usart1_tx.Init.Channel = DMA_CHANNEL_4; hdma_usart1_tx.Init.Direction = DMA_MEMORY_TO_PERIPH; hdma_usart1_tx.Init.PeriphInc = DMA_PINC_DISABLE; hdma_usart1_tx.Init.MemInc = DMA_MINC_ENABLE; hdma_usart1_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE; hdma_usart1_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE; hdma_usart1_tx.Init.Mode = DMA_NORMAL; hdma_usart1_tx.Init.Priority = DMA_PRIORITY_LOW; hdma_usart1_tx.Init.FIFOMode = DMA_FIFOMODE_DISABLE; hdma_usart1_tx.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_FULL; hdma_usart1_tx.Init.MemBurst = DMA_MBURST_SINGLE; hdma_usart1_tx.Init.PeriphBurst = DMA_PBURST_SINGLE; HAL_DMA_Init(&hdma_usart1_tx);
5.在每次需要调用 HAL_UART_Transmit_DMA()函数前通过if((&huart1)->gState == HAL_UART_STATE_READY) 判断一下是否准备好了发送。
6.调用HAL_UART_Transmit_DMA()函数,例如:HAL_UART_Transmit_DMA(&huart1, (uint8_t *)aTxBuffer, TXBUFFERSIZE);
下面是一个完整的例子:
```c
#include "stm32f4xx_hal.h"
/* Private variables ---------------------------------------------------------*/
UART_HandleTypeDef huart1;DMA_HandleTypeDef hdma_usart1_tx;
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_USART1_UART_Init(void);
/* Private functions ---------------------------------------------------------*/
int main(void)
{
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* Configure the system clock */
SystemClock_Config();
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_DMA_Init();
MX_USART1_UART_Init();
/* USER CODE BEGIN 2 */
char aTxBuffer[] = "Hello World!";
uint16_t TXBUFFERSIZE = strlen(aTxBuffer);
if((&huart1)->gState == HAL_UART_STATE_READY)
{
HAL_UART_Transmit_DMA(&huart1, (uint8_t *)aTxBuffer, TXBUFFERSIZE);
}
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* 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};
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
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_HSI;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief USART1 Initialization Function
* @param None
* @retval None
*/
static void MX_USART1_UART_Init(void)
{
/* USER CODE BEGIN USART1_Init 0 */
/* USER CODE END USART1_Init 0 */
/* USER CODE BEGIN USART1_Init 1 */
/* USER CODE END USART1_Init 1 */
huart1.Instance = USART1;
huart1.Init.BaudRate = 115200;
huart1.Init.WordLength = UART_WORDLENGTH_8B;
huart1.Init.StopBits = UART_STOPBITS_1;
huart1.Init.Parity = UART_PARITY_NONE;
huart1.Init.Mode = UART_MODE_TX_RX;
huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart1.Init.OverSampling = UART_OVERSAMPLING_16;
if (HAL_UART_Init(&huart1) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART1_Init 2 */
/* USER CODE END USART1_Init 2 */
}
/**
* Enable DMA controller clock
*/
static void MX_DMA_Init(void)
{
/* DMA controller clock enable */
__HAL_RCC_DMA2_CLK_ENABLE();
/* DMA interrupt init */
/* DMA2_Stream7_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA2_Stream7_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA2_Stream7_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 */
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
```