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19 power management control and status register – Texas Instruments Dual/Single Socket CardBus and UntraMedia Controller PCI7621 User Manual

Page 267

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12−13

12.19 Power Management Control and Status Register

The power management control and status register implements the control and status of the SD host controller. This
register is not affected by the internally generated reset caused by the transition from the D3

hot

to D0 state. See

Table 12−14 for a complete description of the register contents.

Bit

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

Name

Power management control and status

Type

RCU

R

R

R

R

R

R

RW

R

R

R

R

R

R

RW

RW

Default

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Register:

Power management control and status

Offset:

84h

Type:

Read/Clear, Read/Write, Read-only

Default:

0000h

Table 12−14. Power Management Control and Status Register Description

BIT

FIELD NAME

TYPE

DESCRIPTION

15 ‡

PME_STAT

RCU

PME status. This bit defaults to 0.

14−13

DATA_SCALE

R

Data scale. This field returns 0s when read, because the SD host controller does not use the data
register.

12−9

DATA_SELECT

R

Data select. This field returns 0s when read, because the SD host controller does not use the data
register.

8 ‡

PME_EN

RW

PME enable. Enables PME signaling.

7−2

RSVD

R

Reserved. Bits 7−2 return 0s when read.

1−0 ‡

PWR_STATE

RW

Power state. This 2-bit field determines the current power state and sets the SD host controller to a
new power state. This field is encoded as follows:

00 = Current power state is D0.
01 = Current power state is D1.
10 = Current power state is D2.
11 = Current power state is D3hot.

‡ One or more bits in this register are cleared only by the assertion of GRST.

12.20 Power Management Bridge Support Extension Register

The power management bridge support extension register provides extended power-management features not
applicable to the SD host controller; thus, it is read-only and returns 00h when read.

Bit

7

6

5

4

3

2

1

0

Name

Power management bridge support extension

Type

R

R

R

R

R

R

R

R

Default

0

0

0

0

0

0

0

0

Register:

Power management bridge support extension

Offset:

86h

Type:

Read-only

Default:

00h