Hello to everyone,
Thank's to the people who will take time to read my problem.
To be short, I'm working on a system which embed a STM32F205 MCU. This system can communicate with other similar systems by exchanging UART messages over an RS485 physical layer.
A ring topology is used between the systems, which induces that each system has 2 UARTs, one for the messages from the previous system, one for the messages for the next system.
DMA in circular mode is used to send and receive the packets. Currently the system is working well during hours/days/weeks, but at one moment, when it tries to transmit a packet to the UART peripheral using DMA, it stays stuck at the following condition :
while(DMA_GetCmdStatus(DMA2_Stream6) != DISABLE){;}
Below is the part of the code where the DMA transfer is done :
//REDE activation for RS485 transfer
GPIO_SetBits(OUT_DIG_REDE_1_GPIO_PORT,OUT_DIG_REDE_1_PIN);
//Number of data to be transferred
DMA_SetCurrDataCounter(DMA2_Stream6,ModbusStructure->MessageEnvoyeStructure->taille);
//Enable the DMA Tx stream
DMA_Cmd(DMA2_Stream6, ENABLE);
//wait until DMA stream disable meaning transfert complete
while(DMA_GetCmdStatus(DMA2_Stream6) != DISABLE){;}
Here is the DMA initialisation for the corresponding UART
DMA_InitTypeDef DMA_InitStructure;
/* Enable DMAy's AHB1 interface clock */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMAy, ENABLE);
/* Configure DMAy Streamx channel_x from USARTx to the RxBuffer table */
DMA_StructInit(&DMA_InitStructure);
DMA_InitStructure.DMA_Channel = DMA_Channel_x;
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t) &((USARTx)->DR);
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t) &buffer[0];
DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
DMA_InitStructure.DMA_BufferSize = 256;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
/* Attendre la désactivation du DMA avant de le configurer */
while(DMA_GetCmdStatus(DMAy_Streamx)!=DISABLE)
{
DMA_Cmd(DMAy_Streamx, DISABLE);
}
DMA_Init(DMAy_Streamx, &DMA_InitStructure);
USART_DMACmd(USARTx, USART_DMAReq_Tx, ENABLE);
And here is the DMA configuration :
USART_Cmd(EVAL_COM1, DISABLE);
USART_InitStructure.USART_BaudRate = 115200;
USART_InitStructure.USART_WordLength = USART_WordLength_9b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_Even;
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_Init(EVAL_COM1,&USART_InitStructure);
NVIC_InitStructure.NVIC_IRQChannel = USART6_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
USART_ITConfig(EVAL_COM1, USART_IT_TC, ENABLE);
USART_ITConfig(EVAL_COM1, USART_IT_IDLE, ENABLE);
USART_SetAddress(EVAL_COM1, 1);
USART_WakeUpConfig(EVAL_COM1, USART_WakeUp_IdleLine);
USART_Cmd(EVAL_COM1, ENABLE);
/*active DMA */
DMA_ConfigUsartReception(RCC_AHB1Periph_DMA2 ,DMA2_Stream1, DMA_Channel_5, USART6, (uint32_t*) DMARxBuffer1);
DMA_ConfigUsartEmission(RCC_AHB1Periph_DMA2 ,DMA2_Stream6, DMA_Channel_5, USART6, (uint32_t*) DMATxBuffer1);
Also, when the transfer stucked, here are the different values of the parameters of the DMA stream struct. I noticed that the NDTR value is always the number of data to be transmitted minus 1, like only one data have been transmitted.
I already tried when stucked to deInit and Init the UART and DMA but with no luck.
Thanks by advance for anyone who can help me with my problem.
Best regards.
