Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
485
Application DMA Unit—Intel
®
81341 and 81342
5.5
Data Queues
ADMA Ch-0 and Ch-1 each contain six 1 Kbyte data buffers. Four of the buffers are
used when the Transfer Direction field in the ADCR selects the Local Memory (DDR
SDRAM) as the transfer destination (“00”, “10”), while the remaining two buffers are
used when either the Internal Bus or the Host I/O interface is selected as the transfer
destination (“01”, “11”).
ADMA Ch-2 contains four 1 Kbyte data buffers. Two of the buffers are used when the
Transfer Direction field in the ADCR selects the Local Memory (DDR SDRAM) as the
transfer destination (“00”, “10”), while the remaining two buffers are used when either
the Internal Bus or the Host I/O interface is selected as the transfer destination
(“01”, “11”).
These queues temporarily hold data to increase the performance of data transfers in
both directions.
5.5.1
Data Transfer Options
The Transfer Direction field in the ADCR is used to specify the source/destination
interfaces used by the data transfer, the XOR-transfer, the P+Q-transfer, the Zero
Result Buffer Check operation, the P+Q Zero Result Buffer Check Operation, and the
Memory Block Fill operation.
The valid options for this field and how they are applied to these operations are
. This table details the ADMA address registers
associated with the source/destination of a particular operation for a given Transfer
Direction field selection.