4. DMA
120
PowerSpan II User Manual
80A1010_MA001_09
Integrated Device Technology
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4.3.1.1
Direct Mode Transfer Acknowledgment
The following registers are updated during a transfer and can be used to monitor status during DMA
channel activity:
•
DMA Source Address (DMAx_SRC_ADDR) in the
“DMA x Source Address Register” on
•
DMA Destination Address (DMAx_DST_ADDR) in the
“DMA x Destination Address Register”
•
Byte Count (BC[23:0]) field in the
“DMA x Destination Address Register” on page 310
.
4.3.1.2
Terminating a Direct Mode Transfer
The current Direct mode transfer can be stopped by writing 1 to the STOP_REQ bit in the
General Control and Status Register” on page 314
. When this occurs, the channel stops attempting to
buffer data from the source bus. When the remaining buffered source data is written to the destination
bus, the STOP status bit is set.
The channel can be restarted by clearing the STOP status bit (along with any other status bits) and then
writing a 1 to the GO bit.
4.4
Linked-List Mode DMA Operation
In Linked-List (scatter-gather) mode, PowerSpan II steps through a linked series of command packets
in external memory. The DMA is configured with the starting address of this list and independently
reads command packets and executes the transfers specified.
Due to the pipelined nature of DMA channel requests, up to 256-bytes can be transferred after
the user programmed the initial stop request.
Содержание PowerSpan II
Страница 8: ...Contents 8 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 14: ...List of Tables 14 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 18: ...About this Document 18 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 82: ...2 PCI Interface 82 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 112: ...3 Processor Bus Interface 112 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 156: ...7 Interrupt Handling 156 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 380: ...12 Register Descriptions 380 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 394: ...14 Package Information 394 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 414: ...15 AC Timing 414 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 416: ...16 Ordering Information 416 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 420: ...A Hardware Implementation 420 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 428: ...B Typical Applications 428 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...
Страница 432: ...Glossary 432 PowerSpan II User Manual 80A1010_MA001_09 Integrated Device Technology www idt com ...