Yamaha YMF724F specifications 54-55h Power Management Control / Status, 58-59h Acpi Mode

YMF724F

54-55h: Power Management Control / Status

Read / Write

Default: 0000h

Access Bus Width: 8, 16, 32-bit

b15

b14

b13

b12

b11

b10

b9

b8

b7

b6

b5

b4

b3

b2

b1

b0

-

-

-

-

-

-

-

-

-

-

-

-

-

-

PS

b[1:0] ..........PS: Power State

These bits determine the power state of DS-1. DS-1 supports the following power states:

“0”:

D0

“1”:

D1

(not supported)

“2”:

D2

“3”:

D3

hot

When the power state is changed from D3hot to D0, DS-1 resets the PCI Configuration register 00-3Fh. DS-1 transits to D0 Uninitialized state.

Though the power state of this register is changed, the power consumption of DS-1 is not changed. To support low power, Windows driver controls DS-1 Power Control Register.

DS-1 can support the power state of D0, D1, D2 and D3 with ACPI. In this case, set ACPI bit (58-59h: ACPI Mode Register) to “1” to disable Capabilities of PCI Bus Power Management.

58-59h: ACPI Mode

Read / Write

Default: 0000h

Access Bus Width: 8, 16, 32-bit

b15

b14

b13

b12

b11

b10

b9

b8

b7

b6

b5

b4

b3

b2

b1

b0

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

ACPI

b0................ACPI: ACPI Mode Select

This bit select either PCI Bus Power Management or ACPI Mode for power management of DS-1.

“0”: PCI Bus Power Management is used. CAP bit (06-07h: Status Register) and Capabilities Pointer

(34h) are enabled.

(default)

“1”: ACPI Mode is used.

CAP bit and Capabilities Pointer are hardwired “0”, and disabled.

September 21, 1998

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