uart4 DMA causing HardFault error

prasad2 · ‎2010-01-13

Posted on January 13, 2010 at 13:46

prasad2 · ‎2011-05-17

Posted on May 17, 2011 at 13:37

UART4 & DMA init code:

/* Configure USARTx_Tx as alternate function push-pull */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOC, &GPIO_InitStructure);

/* Configure USARTx_Rx as input floating */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOC, &GPIO_InitStructure);

/* UART4 configured as follow:

- BaudRate = 115200 baud

- Word Length = 8 Bits

- One Stop Bit

- No parity

- Hardware flow control disabled (RTS and CTS signals)

- Receive and transmit enabled

*/

USART_InitStructure.USART_BaudRate = 115200;

USART_InitStructure.USART_WordLength = USART_WordLength_8b;

USART_InitStructure.USART_StopBits = USART_StopBits_1;

USART_InitStructure.USART_Parity = USART_Parity_No;

USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;

USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

/* Configure UART4 */

USART_Init(UART4, &USART_InitStructure);

/* Enable the UART4 */

USART_Cmd(UART4, ENABLE);

DMA_InitStructure.DMA_PeripheralBaseAddr = UART4_DR_Base;

DMA_InitStructure.DMA_MemoryBaseAddr = ((u32)pTxBuf);

DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;

DMA_InitStructure.DMA_BufferSize = 0xFF;

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_M2M = DMA_M2M_Disable;

DMA_Init(DMA2_Channel5, &DMA_InitStructure);

/* Enable USART4 DMA TX request */

USART_DMACmd(UART4, USART_DMAReq_Tx, ENABLE); // restart DMA

DMA_InitStructure.DMA_PeripheralBaseAddr = UART4_DR_Base;

DMA_InitStructure.DMA_MemoryBaseAddr = (u32) pRxBuf;

DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;

DMA_InitStructure.DMA_BufferSize = 1;

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_M2M = DMA_M2M_Disable;

DMA_Init(DMA2_Channel3, &DMA_InitStructure);

/* Enable USART4 DMA TX request */

USART_DMACmd(UART4, USART_DMAReq_Rx, ENABLE);

DMA_ITConfig(DMA2_Channel3, DMA_IT_TC, ENABLE);

// enable interrupts

DMA_ITConfig(DMA2_Channel3, DMA_IT_TC, ENABLE); //Rx

DMA_ITConfig(DMA2_Channel5, DMA_IT_TC, ENABLE); //Tx

DMA_ClearITPendingBit function is used to clear the interrupt flag.

Problems:

1. Rx interrupt is not working.

2. Code in execution hits hardfault error but in debug mode works fine.

Please give some suggestions.

chikos33 · ‎2011-05-17

Posted on May 17, 2011 at 13:37

Hi,

I just have some remarks:

- You should enable the Tx DMA request just after the DMA channel configuration (just like you did for Rx). And the USART_Cmd(Enable) should come at the end of the DMA configuration and Requests enable. (but I don't think this could really be the cause of the issue).

- If you have hardfault in execution only and not in debug, it may be related to a timing issue (an event that can be delayed in debug mode), note that the DMA is not stopped when you are in debug mode, it is always running.

- Could you check where exactly the hardfault is happening? And what kind of hardfault you have (by reading the CPU registers, if your tool allow it)?

good luck :)

prasad2 · ‎2011-05-17

Posted on May 17, 2011 at 13:37

Hi,

Thanks for the reply. I checked the exact location for the hardfault. In my program I need to reconfigure the DMA count and DMA transfer location for Tx & for Rx.

By using following code I am using to change the DMA Tx counts.

// clear pending interrupt request

DMA_ClearFlag(DMA2_FLAG_TC5);// clear Tx interrupt request

/* DMA2_Channel5 (triggered by UART4 Tx event) Config */

DMA_Cmd(DMA2_Channel5, DISABLE);

DMA2_Channel5->CNDTR = TxCount;

DMA2_Channel5->CMAR = (u32)pTxBuf;

DMA_Cmd(DMA2_Channel5, ENABLE);

Somewhere in DMA_Cmd I am facing the hardfault issue. If do the single stepping here then there is no hardfault.

Regards,

Prasad

chikos33 · ‎2011-05-17

Posted on May 17, 2011 at 13:37

Hi,

I'm sorry, but I can't see anything wrong in your code.

I just have a ''foolish'' idea: the DMA_Cmd contains |= and &= operators which means the operation is done through two instructions and maybe the interrupt is generated again while these operation are not still finished.

So try to replace DMA_Cmd(DMA2_Channel5, ENABLE); and DMA_Cmd(DMA2_Channel5, DISABLE); by direct register access:

DMA2_Channel5->CCR = xxxxxxx1h (replace with correct value for enable)

DMA2_Channel5->CCR = xxxxxxx0h (replace with correct value for disable)

Otherwise,

Try to modify the optimization level or even the compiler.

I hope someone else have better ideas than mine :-] .

Good luck!

chikos33 · ‎2011-05-17

Posted on May 17, 2011 at 13:37

Hi,

This may be an interesting topic for you:

http://www.st.com/mcu/forums-cat-7723-23.html

?