Hello.I'm using STM32F407, use usart3 set DMA setting baud rate 9600 and use receive void HAL_UARTEx_RxEventCallback(UART_HandleTypeDef *huart, uint16_t Size){if (huart->Instance == USART3) {HAL_UARTEx_ReceiveToIdle_DMA(&huart3, RxBuff, Size);__HAL_D...