现在STM32的DMA成功的将接受所得的字符存入buffer，并通过IDIE中断保证了接受数据能够处理，但是当第二次输入的时候，DMA默认将数据存储在第一次输入的数据后面。请问有什么函数能让DMA将第二次（及以后）的输入从buffer头开始存储？
下面是我的代码
main.c
uint8_t uart2Rx[UART2_BUF_MAX];
uint16_t uart2RxLength;
int main(void)
{
/* USER CODE BEGIN 1 */
int i;
/* 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_USART1_UART_Init();
MX_USART2_UART_Init();
/* USER CODE BEGIN 2 */
USR_UartInit();
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
HAL_Delay(1000);
HAL_UART_Transmit(&huart1, (uint8_t*)"UART1\r\n", 9, 1000);
for(i=0;i<uart1RxLength;i++)
{
HAL_UART_Transmit(&huart1, &uart1Rx[i], 1, 100);
}
HAL_Delay(1000);
HAL_UART_Transmit(&huart1, (uint8_t*)"UART2\r\n", 9, 1000);
for(i=0;i<uart2RxLength;i++)
{
HAL_UART_Transmit(&huart1, &uart2Rx[i], 1, 100);
}
}
/* USER CODE END 3 */
}
void USR_UartInit(void)
{
uart1RxLength = 0;
HAL_UART_Receive_DMA(&huart1, uart1Rx, UART1_BUF_MAX);
__HAL_UART_ENABLE_IT(&huart1, UART_IT_IDLE);
uart2RxLength = 0;
HAL_UART_Receive_DMA(&huart2, uart2Rx, UART2_BUF_MAX);
__HAL_UART_ENABLE_IT(&huart2, UART_IT_IDLE);
}
st32_f1xxit.c
void USART1_IRQHandler(void)
{
/* USER CODE BEGIN USART1_IRQn 0 */
/* USER CODE END USART1_IRQn 0 */
HAL_UART_IRQHandler(&huart1);
/* USER CODE BEGIN USART1_IRQn 1 */
if((__HAL_UART_GET_FLAG(&huart1,UART_FLAG_IDLE)!=RESET))
{
__HAL_UART_DISABLE_IT(&huart1,UART_IT_IDLE);
HAL_UART_DMAStop(&huart1);
uart1RxLength = UART1_BUF_MAX-__HAL_DMA_GET_COUNTER(&hdma_usart1_rx);
__HAL_UART_ENABLE_IT(&huart1, UART_IT_IDLE);
HAL_UART_Receive_DMA(&huart1, uart1Rx, UART1_BUF_MAX);
}
/* USER CODE END USART1_IRQn 1 */
}
