
8201, 8202, 8203, 8204 Acceleration Processor Data Sheet, DS-0157-05
Page 232
Exar Confidential
Attention Button
Present
12
RO
0
Attention Button Present.
When set to one, indicates an Attention
Button is implemented on the card or
module. Valid for the following PCI
Express device types:
Express Endpoint device
Legacy Express Endpoint device
Switch upstream port
Express-to-PCI/PCI-X bridge
Endpoint L1s
Acceptable
Latency[2:0]
11:9
RO
0x3
Endpoint L1s Acceptable Latency.
Acceptable latency that an Endpoint can
withstand due to the transition from L1
state to the L0 state. This value is an
indirect indication of the amount of the
Endpoint's internal buffering. Power
management software uses this value
to compare against the L1 Exit
Latencies reported by all components in
the path between this Endpoint and its
parent Root Port to determine whether
ASPM L1 entry can be used with no loss
of performance.
The 820x requires an endpoint L1
acceptable latency of 8μs maximum.
Endpoint L0s
Acceptable
Latency[2:0]
8:6
RO
0x3
Endpoint L0s Acceptable Latency.
Acceptable total latency that an
Endpoint can withstand due to the
transition from the L0s state to the L0
state. This value is an indirect
indication of the amount of the
Endpoint's internal buffering. Power
management software uses this value
to compare against the L0s exit
latencies reported by all components in
the path between this Endpoint and its
parent Root Port to determine whether
ASPM L0s entry can be used with no
loss of performance.
The 820x requires an endpoint L0
acceptable latency of 4μs maximum.
Extended Tag Field
Supported
5
RO
0x0
Extended Tag Field Supported.
Max supported size of the Tag field
when this function acts as a Requester.
0 = 5-bit Tag field supported (max of
32 outstanding request per Requester).
1 = 8-bit Tag field supported (max of
256 outstanding request per
Requester).
If 8-bit Tags are supported and will be
used, this feature is enabled by setting
the Extended Tag Field Enable bit in the
Device Control register to one.
Field Name
Bits
Type
820x
Value
Description