I've download LPC open, there is a sample described how to use GPDMA to move data from SSP0 buffer to RAM without using linked list.
I've test it without linked list, its works.
But I need to do it with linked list.
Can anyone provide a GPDMA sample code with linked list?
Or help me to edit my code, thanks!
#define BUFFER_SIZE (2000)
uint8 Rx_Buf[2][BUFFER_SIZE];
static uint8_t dmaChSSPRx;
static DMA_TransferDescriptor_t gDMADescriptor[2];
Chip_GPDMA_Init(LPC_GPDMA);
NVIC_DisableIRQ(DMA_IRQn);
NVIC_SetPriority(DMA_IRQn, ((0x01 << 3) | 0x01));
NVIC_EnableIRQ(DMA_IRQn);
Chip_SSP_DMA_Enable(LPC_SSP0);
dmaChSSPRx = Chip_GPDMA_GetFreeChannel(LPC_GPDMA, GPDMA_CONN_SSP0_Rx);
Chip_GPDMA_PrepareDescriptor(LPC_GPDMA, &gDMADescriptor[0], GPDMA_CONN_SSP0_Rx, (uint32_t)&Rx_Buf[0][0], BUFFER_SIZE, GPDMA_TRANSFERTYPE_P2M_CONTROLLER_DMA, &gDMADescriptor[1]);
Chip_GPDMA_PrepareDescriptor(LPC_GPDMA, &gDMADescriptor[1], GPDMA_CONN_SSP0_Rx, (uint32_t)&Rx_Buf[1][0], BUFFER_SIZE, GPDMA_TRANSFERTYPE_P2M_CONTROLLER_DMA, &gDMADescriptor[0]);
Chip_GPDMA_SGTransfer(LPC_GPDMA, dmaChSSPRx, &gDMADescriptor[0], GPDMA_TRANSFERTYPE_P2M_CONTROLLER_DMA);
I received GPDMA_STAT_INTERR interrupt after I called Chip_GPDMA_SGTransfer.
After I check out the register, I found there may be a error in Chip_GPDMA_PrepareDescriptor.
typedef struct DMA_TransferDescriptor {
uint32_t src; /*!< Source address */
uint32_t dst; /*!< Destination address */
uint32_t lli; /*!< Pointer to next descriptor structure */
uint32_t ctrl; /*!< Control word that has transfer size, type etc. */
} DMA_TransferDescriptor_t;
The src is incorrect, it should be GPDMA_CONN_SSP0_Rx not &LPC_SSP0->DR.
This will cause Chip_GPDMA_InitChannelCfg called by Chip_GPDMA_SGTransfer operated incorrect.
Therefore, I've add some code to fix it.
gDMADescriptor[0].src = GPDMA_CONN_SSP0_Rx;
gDMADescriptor[1].src = GPDMA_CONN_SSP0_Rx;
After add this, The first block of Rx_Buf which size is BUFFER_SIZE works fine. But after it finished, DMA_IRQHandler happened constantly by GPDMA_STAT_INTERR
I do not know what I did wrong.
Thank you very much for your assistance.
