PCI Functional Description
Configuration Registers
SYM53C825A/53C825AE Data Manual
3-15
Register 42h
Power Management Capabilities
Read Only
T his register applies to the SYM53C825AE only
and indicates the power management capabilities.
Bits 15-11 PME Support (PME S)
T his field is always set to 00000b because the
SYM53C825AE does not provide a PME sig-
nal.
Bit 10 D2 Support (D2S)
T his device does not support the D2 power
management state.
Bit 9 D1 Support (D1S)
T his device does not support the D1 power
management state.
Bits 8-6 Reserved
Bit 5 Device Specific Initialization (DSI)
T his bit is set to 0 to indicate that the device
requires no special initialization before the
generic class device driver is able to use it.
Bit 4 Auxiliary Power Source (APS)
Because the device does not provide a PME
signal, this bit always returns a 0. T his indi-
cates that no auxiliary power source is required
to support the PME signal in the D3cold
power management state.
Bit 3 PME Clock (PME C)
T his bit always returns a zero value because the
devices do not provide a PME signal.
Bits 2-0 Version (VE R)
T his field is set to 001b to indicate that the
device complies with Revision 1.0 of the PCI
Power Management Interface Specification.
Register 44h
Power Management Control/Status
Read/Write
T his register applies to the SYM53C825AE only
and indicates the power management control and
status descriptions.
Bit 15 PME Status (PST )
T he device always returns a zero for this bit,
indicating that PME signal generation is not
supported from D3cold.
Bits 14-13 Data Scale (DSCL)
T his device does not support the Data register,
therefore this field is always set to 00b.
Bits 12-9 Data Select (DSLT )
T his device does not support the Data reg-
ister, therefore this field is always set to 0000b.
Bit 8 PME E nable (PE N)
T his device always returns a zero for this bit to
indicate that PME assertion is disabled.
Bits 7-2 Reserved
Bits 1-0 Power State (PWS)
T his two bit field determines the current power
state for the function and is used to set the
function to a new power state. T he definition of
the field values are:
00b - D0
01b - Reserved
10b - Reserved
11b - D3hot