
PC Card Controller Programming Model
102
September 2005
SCPS110
4.44 Power Management Control/Status Bridge Support Extensions Register
This register supports PCI bridge-specific functionality. It is required for all PCI-to-PCI bridges. See Table 421
for a complete description of the register contents.
PCI register offset:
A6h (Function 0)
Register type:
Read-only
Default value:
C0h
BIT NUMBER
7
6
5
4
3
2
1
0
RESET STATE
1
0
Table 421. Power Management Control/Status Bridge Support Extensions Register Description
BIT
SIGNAL
TYPE
FUNCTION
7
BPCC_EN
R
Bus power/clock control enable. This bit returns 1b when read. This bit is encoded as:
0 = Bus power/clock control is disabled
1 = Bus power/clock control is enabled (default)
A 0b indicates that the bus power/clock control policies defined in the PCI Bus Power Management
Interface Specification are disabled. When the bus power/clock control enable mechanism is disabled, the
power state field (bits 10) of the power management control/status register (PCI offset A4h, see
Section 4.43) cannot be used by the system software to control the power or the clock of the secondary
bus. A 1b indicates that the bus power/clock control mechanism is enabled.
6
B2_B3
R
B2/B3 support for D3hot. The state of this bit determines the action that is to occur as a direct result of
programming the function to D3hot. This bit is only meaningful if bit 7 (BPCC_EN) is a 1b. This bit is encoded
as:
0 = When the bridge is programmed to D3hot, its secondary bus has its power removed (B3)
1 = When the bridge function is programmed to D3hot, its secondary bus PCI clock is stopped (B2)
(default)
50
RSVD
R
Reserved. These bits return 00 0000b when read.
4.45 Power-Management Data Register
The power-management data register returns 00h when read, because the CardBus functions do not report
dynamic data.
PCI register offset:
A7h (Function 0)
Register type:
Read-only
Default value:
00h
BIT NUMBER
7
6
5
4
3
2
1
0
RESET STATE
0