Atmel Evaluation Kit AT91SAM9X35-EK AT91SAM9X35-EK Data Sheet

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SAM9X35 [DATASHEET]

11055E–ATARM–10-Mar-2014

4. The LLI_W.DMAC_SADDRx field in memory must be set with the starting address of the HSMCI_FIFO 

address.

5. The LLI_W.DMAC_DADDRx field in the memory must be word aligned.
6. Program LLI_W.DMAC_CTRLAx with the following field’s values:

–DST_WIDTH is set to WORD.

–SRC_WIDTH is set to WORD.

–SCSIZE must be set according to the value of HSMCI_DMA, CHKSIZE field.

–BTSIZE is programmed with block_length/4. If BTSIZE is zero, this descriptor is skipped later.

7. Program LLI_W.DMAC_CTRLBx with the following field’s values:

–DST_INCR is set to INCR

–SRC_INCR is set to INCR

–FC field is programmed with peripheral to memory flow control mode.

–SRC_DSCR is set to zero. (descriptor fetch is enabled for the SRC)

–DST_DSCR is set to one. (descriptor fetch is disabled for the DST)

–DIF and SIF are set with their respective layer ID. If SIF is different from DIF, DMA controller is able 

to prefetch data and write HSMCI simultaneously.

8. Program the LLI_W.DMAC_CFGx register for Channel x with the following field’s values:

–FIFOCFG defines the watermark of the DMA channel FIFO.

–DST_REP is set to zero meaning that address are contiguous.

–SRC_H2SEL is set to true to enable hardware handshaking on the destination.

–SRC_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host 

Controller.

9. Program LLI_W.DMAC_DSCRx with the address of LLI_B descriptor. And set DSCRx_IF to the AHB Layer 

ID. This operation actually links the Word oriented descriptor on the second byte oriented descriptor. When 
block_length[1:0] is equal to 0 (multiple of 4) LLI_W.DMAC_DSCRx points to 0, only LLI_W is relevant.

10. Program the channel registers in the Memory for the second descriptor. This descriptor will be byte oriented. 

This descriptor is referred to as LLI_B, standing for LLI Byte oriented.

11. The LLI_B.DMAC_SADDRx field in memory must be set with the starting address of the HSMCI_FIFO 

address.

12. The LLI_B.DMAC_DADDRx is not relevant if previous word aligned descriptor was enabled. If 1, 2 or 3 

bytes are transferred that address is user defined and not word aligned.

13. Program LLI_B.DMAC_CTRLAx with the following field’s values:

–DST_WIDTH is set to BYTE.

–SRC_WIDTH is set to BYTE.

–SCSIZE must be set according to the value of HSMCI_DMA, CHKSIZE field.

–BTSIZE is programmed with block_length[1:0]. (last 1, 2, or 3 bytes of the buffer).

14. Program LLI_B.DMAC_CTRLBx with the following field’s values:

–DST_INCR is set to INCR

–SRC_INCR is set to INCR

–FC field is programmed with peripheral to memory flow control mode.

–Both SRC_DSCR and DST_DSCR are set to 1 (descriptor fetch is disabled) or Next descriptor 

location points to 0.

–DIF and SIF are set with their respective layer ID. If SIF is different from DIF, DMA Controller is able 

to prefetch data and write HSMCI simultaneously.