1.3.8.10 1.4.6.10 1.5.7.10 1.6.6.10 1.7.7.10 1.29.8.10 1.30.5.10 1.31.5.10 1.32.8.10 1.33.5.10 1.37.5.10 1.38.6.10 1.39.5.10 1.40.6.10 DMAC_LinkedListDescriptorSetup Function
C
void DMAC_LinkedListDescriptorSetup (dmac_descriptor_registers_t* currentDescriptor, DMAC_CHANNEL_CONFIG setting, const void *srcAddr, const void *destAddr, size_t blockSize, dmac_descriptor_registers_t* nextDescriptor);
Summary
Sets up linked list descriptor
Description
This function sets up DMA linked list descriptor. Once the descriptor is setup, DMAC_ChannelLinkedListTransfer API can be used to initiate the linked list mode of DMA transfer.
Precondition
-
DMAC should have been initialized by calling the DMAC_Initialize.
-
The Linked List option should have been enabled in MHC DMA manager
Parameters
Param | Description |
---|---|
currentDescriptor | Address of current descriptor |
setting | Block transfer setting of current descriptor |
srcAddr | Source address of the DMAC transfer |
destAddr | Destination address of the DMAC transfer. If the CRC engine is enabled and configured in Memory mode then store the seed to be used by CRC engine in the destination address. |
blockSize | Size of the transfer block in bytes. |
nextDescriptor | Address of next descriptor. if user wants to stop the transfer, this argument should be NULL. |
Returns
None.
Example
uint8_t txPingBuffer[] = "INITIAL_DMA_DATA_FROM_PING_BUFFER"; uint8_t txPongBuffer[] = "initial_dma_data_from_pong_buffer"; __attribute__((__aligned__(16))) static dmac_descriptor_registers_t pTxLinkedListDesc[2]; #define BUFEER0_TX_BTCTRL (DMAC_BTCTRL_STEPSIZE_X1 | DMAC_BTCTRL_SRCINC_Msk | \ DMAC_BTCTRL_BEATSIZE_BYTE | DMAC_BTCTRL_BLOCKACT_INT | DMAC_BTCTRL_VALID_Msk) // Setup DMA linked list DMAC_LinkedListDescriptorSetup (&pTxLinkedListDesc[0], BUFEER0_TX_BTCTRL, (void *)&txPingBuffer[0], (void *)&SERCOM1_REGS->SPIM.SERCOM_DATA, sizeof(txPingBuffer), &pTxLinkedListDesc[1]); DMAC_LinkedListDescriptorSetup (&pTxLinkedListDesc[1], BUFEER0_TX_BTCTRL, (void *)&txPongBuffer[0], (void *)&SERCOM1_REGS->SPIM.SERCOM_DATA, sizeof(txPongBuffer), // this setting will enable continuous transfer, to stop the transfer this argument should be NULL. &pTxLinkedListDesc[0]); // Start the DMA in linked list mode DMAC_ChannelLinkedListTransfer(DMAC_CHANNEL_1, &pTxLinkedListDesc[0]);
Remarks
None.