Altera Arria V Hard IP for PCI Express - Manual (Page 138)

7–40 Chapter 7: IP Core Interfaces
Arria V Hard IP for PCI Express
Arria V Hard IP for PCI Express December 2013 Altera Corporation
User Guide
Power Management Signals
Table 7–17 describes the power management signals.
Table 7–17. Power Management Signals
Signal I/O Description
pme_to_cr I
Power management turn off control register.
Root Port—When this signal is asserted, the Root Port sends the PME_turn_off message.
Endpoint—This signal is asserted to acknowledge the PME_turn_off message by sending
pme_to_ack to the Root Port.
pme_to_sr O
Power management turn off status register.
Root Port—This signal is asserted for 1 clock cycle when the Root Port receives the
pme_turn_off acknowledge message.
Endpoint—This signal is asserted for 1 cycle when the Endpoint receives the
PME_turn_off message from the Root Port.
pm_event I
Power Management Event. This signal is only available for Endpoints.
The Endpoint initiates a a power_management_event message (PM_PME) that is sent to
the Root Port. If the Hard IP is in a low power state, the link exists from the low-power state
to send the message. This signal is positive edge-sensitive.
pm_event_func[2:0] I Specifies the function associated with a Power Management Event.
pm_data[9:0] I
Power Management Data.
This bus indicates power consumption of the component. This bus can only be
implemented if all three bits of
AUX_power (part of the Power Management Capabilities
structure) are set to 0. This bus includes the following bits:
■ pm_data[9:2] : Data Register: This register maintains a value associated with the power
consumed by the component. (Refer to the example below)
■ pm_data[1:0] : Data Scale: This register maintains the scale used to find the power
consumed by a particular component and can include the following values:
b’00: unknown
b’01: 0.1 ×
b’10: 0.01 ×
b’11: 0.001 ×
For example, the two registers might have the following values:
■ pm_data[9:2] : b’1110010 = 114
■ pm_data[1:0] : b’10, which encodes a factor of 0.01
To find the maximum power consumed by this component, multiply the data value by the
data Scale (114 × .01 = 1.14). 1.14 watts is the maximum power allocated to this
component in the power state selected by the
data_select field.
pm_auxpwr I
Power Management Auxiliary Power: This signal can be tied to 0 because the L2 power
state is not supported.