Power management, Power management -13 – Altera Arria 10 Avalon-MM User Manual

Page 39

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Parameter

Value

Description

Slot power limit

0–255

In combination with the Slot power scale value, specifies the upper

limit in watts on power supplied by the slot. Refer to Section 7.8.9 of

the PCI Express Base Specification for more information.

Slot number

0-8191

Specifies the slot number.

Power Management

Table 3-10: Power Management Parameters

Parameter

Value

Description

Endpoint L0s

acceptable

latency

Maximum of 64 ns
Maximum of 128 ns
Maximum of 256 ns
Maximum of 512 ns
Maximum of 1 us
Maximum of 2 us
Maximum of 4 us
No limit

This design parameter specifies the maximum acceptable

latency that the device can tolerate to exit the L0s state for any

links between the device and the root complex. It sets the

read-only value of the Endpoint L0s acceptable latency field of

the

Device Capabilities Register

(0x084).

This Endpoint does not support the L0s or L1 states. However,

in a switched system there may be links connected to switches

that have L0s and L1 enabled. This parameter is set to allow

system configuration software to read the acceptable latencies

for all devices in the system and the exit latencies for each link

to determine which links can enable Active State Power

Management (ASPM). This setting is disabled for Root Ports.
The default value of this parameter is 64 ns. This is the safest

setting for most designs.

Endpoint L1

acceptable

latency

Maximum of 1 us
Maximum of 2 us
Maximum of 4 us
Maximum of 8 us
Maximum of 16 us
Maximum of 32 us
No limit

This value indicates the acceptable latency that an Endpoint

can withstand in the transition from the L1 to L0 state. It is an

indirect measure of the Endpoint’s internal buffering. It sets

the read-only value of the Endpoint L1 acceptable latency field

of the

Device Capabilities Register

.

This Endpoint does not support the L0s or L1 states. However,

a switched system may include links connected to switches

that have L0s and L1 enabled. This parameter is set to allow

system configuration software to read the acceptable latencies

for all devices in the system and the exit latencies for each link

to determine which links can enable Active State Power

Management (ASPM). This setting is disabled for Root Ports.
The default value of this parameter is 1 µs. This is the safest

setting for most designs.

UG-01145_avmm

2015.05.14

Power Management

3-13

Parameter Settings

Altera Corporation

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