4. DMA
123
PowerSpan II User Manual
80A1010_MA001_09
Integrated Device Technology
www.idt.com
Figure 19: Sequence of Operations in a Linked-List Transfer
The DMA walks through the linked-list of command packets until it executes the last packet. When the
operation programmed with that last Command Packet is completed, the DMA sets the DONE bit. The
LAST bit indicates the end of the linked-list.
If the Linked-List mode is started with a non-zero byte count in the DMA Transfer Control Register, a
Direct mode DMA transfer is initiated by PowerSpan II to clear the remaining byte count value. Once
that Direct mode transfer is complete, the DMA then processes the linked-list pointed to in the DMA
Command Packet Pointer Register. This mechanism allows the restart of a linked-list transfer that has
been stopped with the STOP_REQ bit in the
“DMA x General Control and Status Register” on
.
Set GO and CHAIN bit
Await termination
of DMA
Normal
Termination?
Yes
Set up Linked List in
memory space
Configure DMAx_ATTR
Done
Handle
Error
No
Set DMAx_CPP [NCP]