YMF740C Datasheet, PDF (23/44 Pages) List of Unclassifed Manufacturers – DS-1L

YMF740C
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
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PS
b[1:0] ..........PS: Power State
These bits determine the power state of DS-1L. DS-1L supports the following power states:
“0”:
D0
“1”:
D1
(not supported)
“2”:
D2
“3”:
D3_hot
When the power state is changed from D3_hot to D0, DS-1L resets the PCI Configuration register 00-3Fh.
DS-1L transits to D0 Uninitialized state.
Though the power state of this register is changed, the power consumption of DS-1L is not changed. To
support low power, Windows driver controls DS-1L Power Control Register.
DS-1L 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
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- ACPI
b0................ACPI: ACPI Mode Select
This bit select either PCI Bus Power Management or ACPI Mode for power management of DS-1L.
“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.
January 14, 1999
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