February, 2007
Virtual Channel Extended Capability Registers
Register 11-40. 154h Port VC Status and Control (All Ports)
Serial
EEPROM
Bit(s)
Description
Port VC Control
Type
Default
Load VC Arbitration Table
0
RW
Yes
0
Writing 1 updates the VC Arbitration table for the corresponding PEX 8532 port.
Reading this bit always returns 0.
VC Arbitration Select
Selects the VC arbitration type for the corresponding PEX 8532 port. Indicates
the bit number in the Port VC Capability 2 register VC Arbitration Capability
field that corresponds to the arbitration type:
1
RW
Yes
0
0 = bit 0; Round-Robin (Hardware-Fixed) arbitration scheme
1 = bit 1; Weighted Round-Robin with 32 Phases
Select only an arbitration type, that corresponds to a bit set in the VC Arbitration
Capability field. Cannot be modified when more than one LPVC group VC
is enabled.
15:2
16
Reserved
0-0h
Port VC Status
VC Arbitration Table Status
Set to 1 when there is a Write to the VC Arbitration table.
RO
Yes
0
Cleared by the corresponding PEX 8532 port when the port completes loading the
values stored in its VC Arbitration table after software sets the Load VC Arbitration
Table bit.
31:17 Reserved
0-0h
Register 11-41. 158h VC0 Resource Capability (All Ports)
Serial
EEPROM
Bit(s)
Description
Type
Default
Port Arbitration Capability
0
RO
Yes
1
0-0h
0
1 = Non-configurable hardware-fixed port arbitration
The only configuration supported by the PEX 8532.
13:1
14
Reserved
Advanced Packet Switching
Not supported
Cleared to 0.
RO
RO
RO
No
No
No
Reject Snoop Transactions
15
0
Not a PCI Express switch feature; therefore, this bit is cleared to 0.
Maximum Time Slots
Not supported
Cleared to 000_0000b.
22:16
23
000_0000b
0-0h
Reserved
Port Arbitration Table Offset
Not supported
31:24
RO
No
00h
Cleared to 00h.
ExpressLane PEX 8532AA/BA/BB/BC 8-Port/32-Lane Versatile PCI Express Switch Data Book
Copyright © 2007 by PLX Technology, Inc. All Rights Reserved – Version 1.6
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