tm4c1294 mcu UART port DMA sending interrupt got failure

Hi, Jacobi

Thanks for your reply.

We still don't know why bus or memory protection error may occur. Following is the source code we are using, please help to check it. If no error, every time Rs485_Write's excution will cause ISR got called, but sometimes the ISR didn't get called

Init function

void Control_Rs485Init(U32 baud)
{
S32 DoStatus;

DoStatus = 1;
io_manager(IO_MB1_DE,1,&DoStatus);
DoStatus = 0;
io_manager(IO_MB1_RE,1,&DoStatus);
SysCtlPeripheralEnable(SYSCTL_PERIPH_UART4);
GPIOPinConfigure(GPIO_PA3_U4TX);
GPIOPinConfigure(GPIO_PA2_U4RX);
GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_3 | GPIO_PIN_2);
GPIOPadConfigSet(GPIO_PORTA_BASE, GPIO_PIN_3|GPIO_PIN_2, GPIO_STRENGTH_8MA, GPIO_PIN_TYPE_STD_WPU);

UARTConfigSetExpClk(UART4_BASE, g_ui32SysClock, baud,
UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |
UART_CONFIG_PAR_NONE);
UARTFIFOLevelSet(UART4_BASE, UART_FIFO_TX4_8, UART_FIFO_RX4_8);
UARTEnable(UART4_BASE);
//HWREG(UART7_BASE + UART_O_CTL) |= UART_CTL_LBE;

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
uDMAChannelAssign(UDMA_CH19_UART4TX);
uDMAChannelAttributeDisable(UDMA_CHANNEL_UART4TX,
UDMA_ATTR_ALTSELECT |
UDMA_ATTR_HIGH_PRIORITY |
UDMA_ATTR_REQMASK);

uDMAChannelAttributeEnable(UDMA_CHANNEL_UART4TX, UDMA_ATTR_USEBURST);

uDMAChannelControlSet(UDMA_CHANNEL_UART4TX | UDMA_PRI_SELECT,
UDMA_SIZE_8 | UDMA_SRC_INC_8 |
UDMA_DST_INC_NONE |
UDMA_ARB_4);

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
uDMAChannelAssign(UDMA_CH18_UART4RX);

uDMAChannelAttributeDisable(UDMA_CHANNEL_UART4RX,
UDMA_ATTR_ALTSELECT | UDMA_ATTR_USEBURST |
UDMA_ATTR_HIGH_PRIORITY |
UDMA_ATTR_REQMASK);

uDMAChannelControlSet(UDMA_CHANNEL_UART4RX | UDMA_PRI_SELECT,
UDMA_SIZE_8 | UDMA_SRC_INC_NONE |
UDMA_DST_INC_8 |
UDMA_ARB_4);

uDMAChannelControlSet(UDMA_CHANNEL_UART4RX | UDMA_ALT_SELECT,
UDMA_SIZE_8 | UDMA_SRC_INC_NONE |
UDMA_DST_INC_8 |
UDMA_ARB_4);
while (UARTCharsAvail(UART4_BASE)) {
UARTCharGetNonBlocking(UART4_BASE);
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////
UARTIntEnable(UART4_BASE,UART_INT_DMARX|UART_INT_DMATX);
IntEnable(INT_UART4);
}

Write function

Uart_ReturnType Rs485_Write(U8 Handler,U8 *Buf,U16 Length)
{
Uart_ReturnType ret =UART_NOT_OK;
U16 pLength = Length;

if((Buf == NULL)||(Length < 4)||(Length > 1020))
{
return ret;
}
#if 0
while(pLength--)
{
UARTCharPut(UART7_BASE, *Buf++);
}
Rs485TxStatus =1;
#else
if(Handler == 3)
{
//handler 3 for pcs communication using
uDMAChannelTransferSet(UDMA_CHANNEL_UART4TX | UDMA_PRI_SELECT,
UDMA_MODE_BASIC, Buf,
(void *)(UART4_BASE + UART_O_DR),
pLength);
uDMAChannelEnable(UDMA_CHANNEL_UART4TX);
UARTDMAEnable(UART4_BASE, UART_DMA_TX);
Control_Rs485TxStatus =0;
}
else if((Handler == 0)||(Handler == 1))
{
while(pLength--)
{
UARTCharPut(UART7_BASE, *Buf++);
}
Rs485TxStatus =1;
}
else
{
//handler 0,1,2 for 79616
uDMAChannelTransferSet(UDMA_CHANNEL_UART7TX | UDMA_PRI_SELECT,
UDMA_MODE_BASIC, Buf,
(void *)(UART7_BASE + UART_O_DR),
pLength);
uDMAChannelEnable(UDMA_CHANNEL_UART7TX);
UARTDMAEnable(UART7_BASE, UART_DMA_TX);
Rs485TxStatus =0;

}
#endif
ret = UART_OK;
return ret;
}

ISR 

void UART7IntHandler(void)
{
uint32_t ui32Status=0;

ui32Status = UARTIntStatus(UART7_BASE, 1);
UARTIntClear(UART7_BASE, ui32Status);

if(ui32Status & UART_INT_DMATX)
{
if(UDMA_MODE_STOP == uDMAChannelModeGet(UDMA_CHANNEL_UART7TX | UDMA_PRI_SELECT))
{
Rs485TxStatus =1;
uDMAChannelDisable(UDMA_CHANNEL_UART7TX);
UARTDMADisable(UART7_BASE, UART_DMA_TX);
}
else
{
Rs485TxStatus =1;
uDMAChannelDisable(UDMA_CHANNEL_UART7TX);
UARTDMADisable(UART7_BASE, UART_DMA_TX);
}
}

if(ui32Status & UART_INT_DMARX)
{
if(UDMA_MODE_STOP == uDMAChannelModeGet(UDMA_CHANNEL_UART7RX | UDMA_PRI_SELECT))
{
(Rs485DmaRunData[0].step)++;
uDMAChannelTransferSet(UDMA_CHANNEL_UART7RX | UDMA_PRI_SELECT,
UDMA_MODE_PINGPONG,
(void *)(UART7_BASE + UART_O_DR),
(Rs485DmaRunData[0].p[2]), (Rs485DmaRunData[0].len[2]));
}
else if(UDMA_MODE_STOP == uDMAChannelModeGet(UDMA_CHANNEL_UART7RX | UDMA_ALT_SELECT))
{
(Rs485DmaRunData[0].step)++;
uDMAChannelTransferSet(UDMA_CHANNEL_UART7RX | UDMA_ALT_SELECT,
UDMA_MODE_PINGPONG,
(void *)(UART7_BASE + UART_O_DR),
(Rs485DmaRunData[0].p[3]), (Rs485DmaRunData[0].len[3]));
}
else
{
(Rs485DmaRunData[0].step) =0xff;
uDMAChannelDisable(UDMA_CHANNEL_UART7RX);
UARTDMADisable(UART7_BASE, UART_DMA_RX);
}
if((Rs485DmaRunData[0].step) == 4)
{
(Rs485DmaRunData[0].step) = 0;
Rs485RxStatus =1;
uDMAChannelDisable(UDMA_CHANNEL_UART7RX);
UARTDMADisable(UART7_BASE, UART_DMA_RX);
}
}
}

Hello Lijun,

Honestly, its a bit hard to follow your code with how disjointed the setup is and I am not sure if that is causing some of the issue.

But also seeing the variable length used for the uDMAChannelTransferSet for UART4, I am wondering if maybe you need to look into the uDMAChannelControlSet settings you have if the size of the transfers configured there is too high. That could be one possible cause for an error I could think of.

Beyond that I think you need to dig into your code deeper to understand what is triggering the error cases via debugging what is occurring in the system when the errors are being triggered. Look for elements like not enough data being available or incorrect addresses for buffers or even stack overflow potentially (though I would expect that would crash your code entirely).

Best Regards,

Ralph Jacobi