Intel
®
81341 and 81342—Application DMA Unit
Intel
®
81341 and 81342 I/O Processors
Developer’s Manual
December 2007
530
Order Number: 315037-002US
5.16.8
ADMA Byte Count Register x — ABCRx
The ADMA Byte Count Register (ABCR) contains the number of bytes to transfer for an
operation and an operation status field which are updated when the Status Write Back
Enable in the ADCR is set. This is a read-only register that is loaded from the Byte
Count word in a basic or full chain descriptor. It allows for a maximum transfer of 16
Mbytes. A value of zero is a valid byte count and results in no data transfers.
Note:
Anytime this register is read by the 81341 and 81342, it contains the number of bytes
left to transfer. Note that during an operation
valid data may be present in the
Application DMA store queue. This register is decremented by 1 Kbyte granularity when
all of the programmed operations have completed on 1 Kbytes of all enabled sources,
or simply decremented to 0000H when the byte count is less than 1 Kbytes.
Table 323. ADMA Byte Count Register x — ABCRx
Bit
Default
Description
31
0
2
Transfer Complete - This bit is set when the ADMA completes the processing of the descriptor.
Note:
The ADMA updates this status in memory
only
by updating the Byte Count Word of the current
descriptor (the fourth word of the descriptor pointed to by the ADAR).
30
0
2
Zero Result Buffer Error - This bit is set when the bit wise XOR computed across the data blocks
specified by the SARx registers results in the detection of a non-zero result (i.e., an invalid parity block).
For a P+Q Zero Result Buffer Check, this represents an error on the P check data.
Note:
The ADMA updates this status in memory
only
by updating the Byte Count Word of the current
descriptor (the fourth word of the descriptor pointed to by the ADAR).
29
0
2
Zero Result Buffer Error Q - For a P+Q Zero Result Buffer check, this bit is set when the bit wise XOR
computed across the Galois multiplied data blocks specified by the SARx registers results in the
detection of a non-zero result (i.e., an invalid Q block).
Note:
The ADMA updates this status in memory
only
by updating the Byte Count Word of the current
descriptor (the fourth word of the descriptor pointed to by the ADAR).
28
0
2
Reserved
27
0
2
Reserved
26:24
000
2
Host I/O Interface Function Number - This field is used to program the host I/O interface function
number (0-7) that the current descriptor is associated with.
23:00
000000H Byte Count - is the number of bytes to transfer for an operation.
Host
IOP
Attributes
Attributes
28
24
20
16
12
8
4
0
31
ro
na
ro
na
ro
na
rv
na
rv
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
ro
na
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible
Channel #
0
1
2
Internal bus address offset
0030H
0230H
0430H