Atmel SAM9X25, Manual

Page: 495 / 1145

495
11054A–ATARM–27-Jul-11
SAM9X25
495
11054A–ATARM–27-Jul-11
SAM9X25
Figure 31-14. DMAC Transfer Replay Mode is Enabled for the Source and Contiguous Destination Address
Multi-buffer DMAC Transfer with Linked List for Source and Contiguous Destination Address (Row 2)
1. Read the Channel Enable register to choose a free (disabled) channel.
2. Set up the linked list in memory. Write the control information in the
LLI.DMAC_CTRLAx and LLI.DMAC_CTRLBx register location of the buffer descriptor
for each LLI in memory for channel x. For example, in the register, you can program the
following:
a. Set up the transfer type (memory or non-memory peripheral for source and desti-
nation) and flow control device by programming the FC of the DMAC_CTRLBx
register.
b. Set up the transfer characteristics, such as:
– i. Transfer width for the source in the SRC_WIDTH field.
– ii. Transfer width for the destination in the DST_WIDTH field.
– iii. Source AHB master interface layer in the SIF field where source resides.
– iv. Destination AHB master interface layer in the DIF field where destination resides.
Channel Enabled by
software
Buffer Transfer
Replay mode for SADDRx,
Contiguous mode for DADDRx
CTRLAx, CTRLBx
Channel Disabled by
hardware
Buffer Complete interrupt
generated here
Buffer Transfer Complete
interrupt generated here
yes
no
no
yes
Stall until STALLED field is
cleared by software writing
KEEPON Field
DMA_EBCIMR[x]=1?
Is HDMA in Row1of
HDMA State Machine Table?