Visible to Intel only — GUID: nik1410564873683
Ixiasoft
Visible to Intel only — GUID: nik1410564873683
Ixiasoft
5.13. Power Management Signals
Signal |
Direction |
Description |
---|---|---|
pme_to_cr | Input |
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 | Output |
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 | Input |
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 exits from the low-power state to send the message. This signal is positive edge-sensitive. |
pm_data[9:0] | Input |
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:
For example, the two registers might have the following values:
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 | Input |
Power Management Auxiliary Power: This signal can be tied to 0 because the L2 power state is not supported. |
Bits |
Field |
Description |
---|---|---|
[31:24] |
Data register | This field indicates in which power states a function can assert the PME# message. |
[23:16] |
reserved | — |
[15] |
PME_status | When set to 1, indicates that the function would normally assert the PME# message independently of the state of the PME_en bit. |
[14:13] |
data_scale | This field indicates the scaling factor when interpreting the value retrieved from the data register. This field is read-only. |
[12:9] |
data_select | This field indicates which data should be reported through the data register and the data_scale field. |
[8] |
PME_EN | 1: indicates that the function can assert PME#0: indicates that the function cannot assert PME# |
[7:2] |
reserved | — |
[1:0] |
PM_state | Specifies the power management state of the operating condition being described. The following encodings are defined:
A device returns 2b’11 in this field and Aux or PME Aux in the type register to specify the D3-Cold PM state. An encoding of 2b’11 along with any other type register value specifies the D3-Hot state. |