PCI6621 datasheet(73/204 Pages) TI

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Table 3−17. Function 5 Power-Management Registers

OFFSET

Power-management capabilities

Next item pointer

Capability ID

44h

Data

Power-management control/status register bridge support extensions

Power-management control/status (CSR)

48h

3.8.9

CardBus Bridge Power Management

The PCI Bus Power Management Interface Specification for PCI to CardBus Bridges was approved by PCMCIA in

December of 1997. This specification follows the device and bus state definitions provided in the PCI Bus Power

Management Interface Specification published by the PCI Special Interest Group (SIG). The main issue addressed

in the PCI Bus Power Management Interface Specification for PCI to CardBus Bridges is wake-up from D3hot or D3cold

without losing wake-up context (also called PME context).

The specific issues addressed by the PCI Bus Power Management Interface Specification for PCI to CardBus Bridges

for D3 wake-up are as follows:

•

Preservation of device context. The specification states that a reset must occur during the transition from

D3 to D0. Some method to preserve wake-up context must be implemented so that the reset does not clear

the PME context registers.

•

Power source in D3cold if wake-up support is required from this state.

The Texas Instruments PCI6x21/PCI6x11 controller addresses these D3 wake-up issues in the following manner:

•

Two resets are provided to handle preservation of PME context bits:

−

Global reset (GRST) is used only on the initial boot up of the system after power up. It places the

PCI6x21/PCI6x11 controller in its default state and requires BIOS to configure the controller before

becoming fully functional.

−

PCI reset (PRST) has dual functionality based on whether PME is enabled or not. If PME is enabled,

then PME context is preserved. If PME is not enabled, then PRST acts the same as a normal PCI reset.

Please see the master list of PME context bits in Section 3.8.11.

•

Power source in D3cold if wake-up support is required from this state. Since VCC is removed in D3cold, an

auxiliary power source must be supplied to the PCI6x21/PCI6x11 VCC terminals. Consult the PCI14xx

Implementation Guide for D3 Wake-Up or the PCI Power Management Interface Specification for PCI to

CardBus Bridges for further information.

3.8.10 ACPI Support

The Advanced Configuration and Power Interface (ACPI) Specification provides a mechanism that allows unique

pieces of hardware to be described to the ACPI driver. The PCI6x21/PCI6x11 controller offers a generic interface that

is compliant with ACPI design rules.

Two doublewords of general-purpose ACPI programming bits reside in PCI6x21/PCI6x11 PCI configuration space

at offset 88h. The programming model is broken into status and control functions. In compliance with ACPI, the top

level event status and enable bits reside in the general-purpose event status register (PCI offset 88h, see

Section 4.32) and general-purpose event enable register (PCI offset 89h, see Section 4.33). The status and enable

bits are implemented as defined by ACPI and illustrated in Figure 3−15.

Event Output

Event Input

Enable Bit

Status Bit

Figure 3−15. Block Diagram of a Status/Enable Cell

The status and enable bits generate an event that allows the ACPI driver to call a control method associated with the

pending status bit. The control method can then control the hardware by manipulating the hardware control bits or

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