Power Management Signals - Altera Cyclone V User Manual

5–30

Power Management Signals

Table 5–17
Table 5–17. Power Management Signals
Signal I/O
pme_to_cr
O
pme_to_sr
pm_event
pm_event_func[2:0]
pm_data[9:0]
pm_auxpwr
Cyclone V Hard IP for PCI Express
describes the power management signals.
Power management turn off control register.
Root Port—When this signal is asserted, the Root Port sends the PME_turn_off message.
I
Endpoint—This signal is asserted to acknowledge the PME_turn_off message by sending
pme_to_ack to the Root Port.
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.
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
I
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.
I Specifies the function associated with a Power Management Event.
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
I
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.
Power Management Auxiliary Power: This signal can be tied to 0 because the L2 power
I
state is not supported.
Chapter 5: IP Core Interfaces
Description
November 2011 Altera Corporation
Power Management Signals