Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
173
Address Translation Unit (PCI-X)—Intel
®
81341 and 81342
2.13.27 ATU Maximum Latency Register - ATUMLAT
ATU Maximum Latency Register bit definitions adhere to PCI Local Bus Specification,
Revision 2.3. This register specifies how often the device needs to access the PCI bus in
increments of 8 PCI clocks.
This register and the Minimum Grant Register are information-only registers which the
configuration uses to determine how often a bus master typically requires access to the
PCI bus and the duration of a typical transfer when it does acquire the bus. This
information is useful in determining the values to be programmed into the bus master
latency timers and in programming the algorithm to be used by the PCI bus arbiter.
Table 50. ATU Maximum Latency Register - ATUMLAT
Bit
Default
Description
07:00
00H
Specifies frequency (how often) the device needs to access the PCI bus in increments of 8 PCI clocks. A
zero value indicates the device has no stringent requirement.
PCI
IOP
Attributes
Attributes
7
4
0
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible
Register Offset
+03FH