Posted on March 27, 2018 at 12:55Hello,
I have ported an exisiting code for a UART peripheral that uses DMA to copy the data from stm32F4 to an stm32L4
When I send a character through the UART bus, and wait for the IDLE line detection interrupt to accure, I got the following :
char received in the RDR (receive data register), but is not copied in the DMA Rx buffer that I defined previous
Here how I setup the UART
_t_DeviceHandle.Instance = USART3;
_t_
Device
Handle.Init.BaudRate = 9600;
_t_
Device
Handle.Init.WordLength = UART_WORDLENGTH_8B;
_t_
Device
Handle.Init.StopBits = UART_STOPBITS_1;
_t_
Device
Handle.Init.Parity = UART_PARITY_NONE;
_t_
Device
Handle.Init.Mode = UART_MODE_TX_RX;
_t_
Device
Handle.Init.HwFlowCtl = UART_HWCONTROL_NONE;// UART_HWCONTROL_RTS_CTS;
_t_
Device
Handle.Init.OverSampling = UART_OVERSAMPLING_16;
_t_
Device
Handle.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
_t_
Device
Handle.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
if (HAL_UART_Init(&_t_DeviceHandle) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
/* Configure USART interrupt */
HAL_NVIC_SetPriority(USART3_IRQn, 5, 0U);
HAL_NVIC_EnableIRQ(USART3_IRQn);
}
Here is how I setup my DMA
__HAL_RCC_DMA1_CLK_ENABLE();
_t_DeviceRxDmaStreamHandle.Instance =
DMA1_Channel3
;
_t_
Device
RxDmaStreamHandle.Init.Direction = DMA_PERIPH_TO_MEMORY;
_t_
Device
RxDmaStreamHandle.Init.PeriphInc = DMA_PINC_DISABLE;
_t_
Device
RxDmaStreamHandle.Init.MemInc = DMA_MINC_ENABLE;
_t_
Device
RxDmaStreamHandle.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
_t_
Device
RxDmaStreamHandle.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
_t_
Device
RxDmaStreamHandle.Init.Mode = DMA_NORMAL;
_t_
Device
RxDmaStreamHandle.Init.Priority = DMA_PRIORITY_HIGH;
if(HAL_DMA_Init(&_t_
Device
RxDmaStreamHandle) != HAL_OK)
{
assert_failed((uint8_t*)__FILE__, __LINE__);
}
// linking DMA channel with the UART RX
__HAL_LINKDMA(&_t_
Device
Handle, hdmarx, _t_
Device
RxDmaStreamHandle);
// defining memory address, size...etc
HAL_UART_Receive_DMA(&_t_
Device
Handle, __au8_StorageBuffer, __u16_MaxDataLength);
I checked the DMA register and they seemed correct :
CCR3->EN = 1 // channel is enabled
CCR3->TCIE = 1 // transfert complete interrupt is enabled
CCR3->TEIE = 1 // error interrupt enabled
CCR3->DIR = 0 // from peripheral to memory
CPAR3 has the UART RDR address
CMAR3 has the Rx buffer address.
I'm not sure what I missed here. Any suggesting on how I can debug this further ?
Thank you
regards
#dma #stm32l4 #hal #uart
