Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Data Sheet
Product codes
AT91SAM9M10-G45-EK
933
SAM9M10 [DATASHEET]
6355F–ATARM–12-Mar-13
Figure 41-2.
DMAC Transfer Hierarchy for Non-Memory Peripheral
Figure 41-3.
DMAC Transfer Hierarchy for Memory
Buffer:
A buffer of DMAC data. The amount of data (length) is determined by the flow controller. For transfers
between the DMAC and memory, a buffer is broken directly into a sequence of AMBA bursts and AMBA single
transfers.
transfers.
For transfers between the DMAC and a non-memory peripheral, a buffer is broken into a sequence of DMAC trans-
actions (single and chunks). These are in turn broken into a sequence of AMBA transfers.
actions (single and chunks). These are in turn broken into a sequence of AMBA transfers.
Transaction:
A basic unit of a DMAC transfer as determined by either the hardware or software handshaking inter-
face. A transaction is only relevant for transfers between the DMAC and a source or destination peripheral if the
source or destination peripheral is a non-memory device. There are two types of transactions: single transfer and
chunk transfer.
source or destination peripheral is a non-memory device. There are two types of transactions: single transfer and
chunk transfer.
–
Single transfer:
The length of a single transaction is always 1 and is converted to a single AMBA
access.
–
Chunk transfer:
The length of a chunk is programmed into the DMAC. The chunk is then converted
into a sequence of AHB access.DMAC executes each AMBA burst transfer by performing incremental
bursts that are no longer than 16 beats.
bursts that are no longer than 16 beats.
DMAC transfer:
Software controls the number of buffers in a DMAC transfer. Once the DMAC transfer has com-
pleted, then hardware within the DMAC disables the channel and can generate an interrupt to signal the
completion of the DMAC transfer. You can then re-program the channel for a new DMAC transfer.
completion of the DMAC transfer. You can then re-program the channel for a new DMAC transfer.
HDMA Transfer
DMA Transfer
Level
Level
Buffer
Buffer
Buffer
Buffer Transfer
Level
Level
Chunk
Transfer
Chunk
Transfer
Chunk
Transfer
Single
Transfer
DMA Transaction
Level
Level
Burst
Transfer
AMBA
Burst
Transfer
AMBA
Burst
Transfer
AMBA
Single
Transfer
AMBA
AMBA Transfer
Level
Level
Single
Transfer
AMBA
HDMA Transfer
DMA Transfer
Level
Level
Buffer
Buffer
Buffer
Buffer Transfer
Level
Level
Burst
Transfer
AMBA
Burst
Transfer
AMBA
Burst
Transfer
AMBA
Single
Transfer
AMBA
AMBA Transfer
Level
Level