ATSAM3U-EK Atmel, ATSAM3U-EK Datasheet - Page 1016

• Manufacturer Part Number: ATSAM3U-EK
• Description: KIT EVAL FOR AT91SAM3U CORTEX
• Manufacturer: Atmel
• Type: MCUr

Specifications of ATSAM3U-EK

• Contents: Board
• Processor To Be Evaluated: SAM3U
• Data Bus Width: 32 bit
• Interface Type: RS-232, USB
• Operating Supply Voltage: 3 V
• Silicon Manufacturer: Atmel
• Core Architecture: ARM
• Core Sub-architecture: Cortex - M3
• Silicon Core Number: SAM3U4E
• Silicon Family Name: SAM3U
• Kit Contents: Board CD Docs
• Rohs Compliant: Yes
• For Use With/related Products: AT91SAM3U
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

1016
SAM3U Series
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.
For transfers between the DMAC and a non-memory peripheral, a buffer is broken into a
sequence of DMAC transactions (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 interface. 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.
DMAC transfer: Software controls the number of buffers in a DMAC transfer. Once the DMAC
transfer has completed, 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.
Single-buffer DMAC transfer: Consists of a single buffer.
Multi-buffer DMAC transfer: A DMAC transfer may consist of multiple DMAC buffers. Multi-buf-
fer DMAC transfers are supported through buffer chaining (linked list pointers), auto-reloading of
channel registers, and contiguous buffers. The source and destination can independently select
which method to use.
Channel locking: Software can program a channel to keep the AHB master interface by locking
the arbitration for the master bus interface for the duration of a DMAC transfer, buffer, or chunk.
Transfer
AMBA
Burst
Buffer
– Single transfer: The length of a single transaction is always 1 and is converted to a
– Chunk transfer: The length of a chunk is programmed into the DMAC. The chunk is
– Linked lists (buffer chaining) – A descriptor pointer (DSCR) points to the location
– Contiguous buffers – Where the address of the next buffer is selected to be a
single AMBA access.
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.
in system memory where the next linked list item (LLI) exists. The LLI is a set of
registers that describe the next buffer (buffer descriptor) and a descriptor pointer
register. The DMAC fetches the LLI at the beginning of every buffer when buffer
chaining is enabled.
continuation from the end of the previous buffer.
Transfer
AMBA
Burst
Buffer
HDMA Transfer
Transfer
AMBA
Burst
Buffer
Transfer
AMBA
Single
DMA Transfer
Level
Buffer Transfer
Level
AMBA Transfer
Level
6430D–ATARM–25-Mar-11