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186 21555 Non-Transparent PCI-to-PCI Bridge User Manual
List of Registers
.
Table 119. Power Management Capabilities Register
Bits [14:9,5,2:0] are loadable through the serial ROM or are programmable by the local processor.
• Primary byte offset: DF:DEh
• Secondary byte offset: DF:DEh
Bit Name R/W Description
2:0 PM Version R/(WS)
Power Management Version. Loadable by serial ROM.
Reset value is Signal 001b to indicate that this device is compliant to the PCI
Power Management Interface Specification, Revision 1.1.
3 PME Clock R
Clock Required for PME# Assertion. Reads as 1 to indicate that a clock is
required to assert PME#, when any of bits [15:11] in this register are
asserted. Read as 0 when bits [15:11] are all 0, indicating that the 21555
does not assert PME#.
4APS R
Auxiliary Power Source. Not defined since the 21555 does not have PME#
support from D3
cold
. Read only as 0.
5DSI R/(WS)
Device
-Specific Initialization. Loadable by serial ROM.
• When 0, indicates that the 21555 does not have device
-specific
initialization requirements.
• When 1, indicates that the 21555 has device
-specific initialization
requirements.
• Reset value is 0
8:6 Reserved R Reserved. Read only as 0.
9 D1 Support R/(WS)
D1 Power State Support Indicator. Loadable by serial ROM.
• When 0, indicates that the 21555 does not support the D1 power
management state.
• When 1, indicates that the 21555 supports the D1 power management
state.
• Reset value is 0
10 D2 Support R/(WS)
D2 Power State Support Indicator. Loadable by serial ROM.
• When 0, indicates that the 21555 does not support the D2 power
management state.
• When 1, indicates that the 21555 supports the D2 power management
state.
• Reset value is 0
15:11
PME
Support
R/(WS)
PME# support. Indicates whether the 21555 asserts p_pme_l when in a
given power state. Bit 11 corresponds to D0; bit 15 corresponds to D3
cold
.
Bits [14:11] are loadable by serial ROM.
Bit 15 always reads as 0 and is not loaded by serial ROM nor writable from
the secondary interface, since the 21555 never asserts PME# when in
D3
cold
.
Reset value is 0 to indicate that the 21555 does not implement the PME#
pin.