Intel
®
81341 and 81342—Address Translation Unit (PCI-X)
Intel
®
81341 and 81342 I/O Processors
Developer’s Manual
December 2007
198
Order Number: 315037-002US
2.13.56 PCI-X Status Register - PCIXSR
This register identifies the capabilities and current operating mode of ATU when
operating in the PCI-X mode.
Table 79. PCI-X Status Register - PCIXSR (Sheet 1 of 2)
Bit
Default
Description
31:30
00
2
Reserved
29
0
2
Received Split Completion Error Message - This bit is set when the device receives a Split Completion
Message with the Split Completion Error attribute bit set. Once set, this bit remains set until software
writes a 1 to this location.
0 = no Split Completion error message received.
1 = a Split Completion error message has been received.
28:26
001
2
Designed Maximum Cumulative Read Size (DMCRS) - The value of this register depends on the setting
of the Maximum Memory Read Byte Count field of the PCIXCMD register:
DMCRS Max ADQs Maximum Memory Read Byte Count Register Setting
1
16
512 (Default)
2
32
1024
2
32
2048
2
32
4096
25:23
011
2
Designed Maximum Outstanding Split Transactions - The 81341 and 81342
can have up to four
outstanding split transactions.
22:21
01
2
Designed Maximum Memory Read Byte Count - The 81341 and 81342
can generate memory reads with
byte counts up to 1024 bytes.
20
1
2
81341 and 81342
is a complex device.
19
0
2
Unexpected Split Completion - This bit is set when an unexpected Split Completion with this device’s
Requester ID is received. Once set, this bit remains set until software writes a 1 to this location.
0 = no unexpected Split Completion has been received.
1 = an unexpected Split Completion has been received.
18
0
2
Split Completion Discarded - This bit is set when the device discards a Split Completion because the
requester would not accept it. See Section 5.4.4 of the PCI-X Protocol Addendum to the PCI Local Bus
Specification, Revision 2.0 for details. Once set, this bit remains set until software writes a 1 to this
location.
0 = no Split Completion has been discarded.
1 = a Split Completion has been discarded.
Note:
The 81341 and 81342
never
sets this bit since there is no Inbound address responding to
Inbound Read Requests with Split Responses (Memory or Register) that has “read side effects.”
17
1
2
81341 and 81342
is a 133 MHz capable device.
16
32BITPCI#
81341 and 81342 can be configured to identify the add-in card to the system as 64-bit or 32-bit wide
via a user-configurable strap (
32BITPCI#
). This strap, by default, identifies the 81341 and 81342
subsystem as 64-bit unless the user attaches the appropriate pull-down resistor to the strap.
0 = The bus is 32 bits wide.
1 = The bus is 64 bits wide.
PCI
IOP
Attributes
Attributes
28
24
20
16
12
8
4
0
31
rv
rv
rv
rv
rc
rc
ro
ro
ro
ro
ro
ro
ro
ro
ro
ro
ro
ro
ro
ro
ro
ro
ro
ro
rc
rc
ro
ro
ro
ro
ro
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
ro
ro
ro
ro
ro
ro
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible
Register Offset
+0D4H