I'm trying to use dma with uart in stm32f746 nucleo in receiving mode i can receive correct data in first use when i try to receive again receiving buffer doesn't change its initial values before receiving although i can get receive complete signal callback every time
/ Main Loop */ while(1) { HAL_GPIO_TogglePin(LED_PORT,LED_GREEN); // Led Example HAL_Delay(200); pRxData[0]=5; pRxData[1]=0; // HAL_UART_Receive_IT(&UartHandle,pRxData,2); if( HAL_UART_Receive_DMA(&UartHandle,pRxData,2)==HAL_OK); // UART-DMA-IT Example { while (UartReady != SET) // wait for msg len { HAL_GPIO_WritePin(LED_PORT,LED_GREEN,1); HAL_Delay(20); HAL_GPIO_WritePin(LED_PORT,LED_GREEN,0); HAL_Delay(400); } UartReady = RESET; // reset transmition flag LEN = pRxData[0]+pRxData[1]*256; // calc msg length if ( LEN > 0 ) { pTxData[0]= 25;//LEN; // ACK //HAL_UART_Transmit_IT(&UartHandle,pTxData,1); if(HAL_UART_Transmit_DMA(&UartHandle,pTxData,1)==HAL_OK); { while (UartReady != SET) { HAL_Delay(1); } UartReady = RESET; if(HAL_UART_Receive_IT(&UartHandle,pRxData,LEN)==HAL_OK) { //HAL_UART_Receive_DMA(&UartHandle,pRxData,LEN); while (UartReady != SET) // waiting loop for msg { HAL_GPIO_WritePin(LED_PORT,LED_GREEN,1); HAL_Delay(300); HAL_GPIO_WritePin(LED_PORT,LED_GREEN,0); HAL_Delay(50); } UartReady = RESET; if (MBU_StrCompareNC(pRxData,"LED_ON_BLUE",LEN)==0) { HAL_GPIO_WritePin(LED_PORT,LED_BLUE,1); } if (MBU_StrCompareNC(pRxData,"LED_OFF_BLUE",LEN)==0) { HAL_GPIO_WritePin(LED_PORT,LED_BLUE,0); } if (MBU_StrCompareNC(pRxData,"LED_ON_RED",LEN)==0) { HAL_GPIO_WritePin(LED_PORT,LED_RED,1); } if (MBU_StrCompareNC(pRxData,"LED_OFF_RED",LEN)==0) { HAL_GPIO_WritePin(LED_PORT,LED_RED,0); } } HAL_UART_Abort(&UartHandle); } } } } }