February, 2007
PCI Express Capability Registers
Register 11-29. 80h Slot Status and Control (All Ports) (Cont.)
Serial
Bit(s)
Description
Command Completed
Ports
Type
Default
EEPROM
Upstream
RO
RW1C
RO
No
0
Do not change for upstream port.
20
Set to 1 when the Hot Plug Controller on the
corresponding PEX 8532 downstream port slot
completes an issued command.
Downstream
Upstream
Yes
No
0
0
MRL Sensor State
Do not change for upstream port.
Reveals the corresponding PEX 8532 downstream
port MRL sensor’s current state.
0 = MRL sensor closed
1 = MRL sensor open
21
Downstream
Upstream
RO
RO
Yes
No
0
0
Presence Detect State
Do not use for upstream port.
Reveals the corresponding PEX 8532 downstream
port’s current Presence state. Presence is determined
from one of two sources, depending on the state
of the HPC Inband Presence Detect Enable bit
(1E0h[5]):
•
If the HPC Inband Presence Detect Enable bit
is cleared (offset 1E0h[5]=0, default), Presence
Detect is input from the HP_PRSNTx#
signal on the corresponding PEX 8532
downstream port
22
Downstream
RO
Yes
0
•
If the HPC Inband Presence Detect Enable bit
is set (offset 1E0h[5]=1), Presence Detect is
input from the SerDes Receiver Detect on the
corresponding PEX 8532 downstream port
0 = Slot is empty, or device is not present
1 = Slot is occupied, or device is present
31:23 Reserved
0-0h
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
189
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