AMD Geode SC1201 User Manual

Page 250

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250

AMD Geode™ SC1200/SC1201 Processor Data Book

Core Logic Module - SMI Status and ACPI Registers - Function 1

32579B

13

SLP_EN (Sleep Enable). (Write Only) Allow the system to sequence into the sleeping state associated with the SLP_TYPx
(bits [12:10]).

0: Disable.

1: Enable.

This is a write only bit and reads of this bit always return a 0.

The ACPI state machine always waits for an SMI (any SMI) to be generated and serviced before transitioning into a Sleep
state.

If F1BAR1+I/O Offset 18h[9] = 1, an SMI is generated when SLP_EN is set.

Top level SMI status is reported at F1BAR0+I/O Offset 00h/02h[2].
Second level SMI status is reported at F1BAR0+I/O Offset 20h/22h[2].

12:10

SLP_TYPx (Sleep Type). Defines the type of Sleep state the system enters when SLP_EN (bit 13) is set.

000: Sleep State S0 (Full on)

100: Sleep State SL4

001: Sleep State SL1

101: Sleep State SL5 (Soft off)

010: Sleep State SL2

110: Reserved

011: Sleep State SL3

111: Reserved

9:3

Reserved. Set to 0.

2

GBL_RLS (Global Release). (Write Only) This write only bit is used by ACPI software to raise an event to the BIOS soft-
ware (i.e., it generates an SMI to pass execution control to the BIOS).

0: Disable.

1: Enable.

This is a write only bit and reads of this bit always return a 0.

To generate an SMI, ACPI software writes the GBL_RLS bit which in turn sets the BIOS_STS bit (F1BAR1+I/O Offset
0Eh[0]) and raises a PME. For the PME to generate an SMI, set BIOS_EN (F1BAR1+I/O Offset 0Fh[0] to 1).

The top level SMI status is reported at F1BAR0+I/O offset 00h/02h.
Second level status is at F1BAR0+I/O Offset 22h[5].

1

BM_RLD (Bus Master RLD). If the processor is in the C3 state and a bus master request is generated, force the processor
to transition to the C0 state.

0: Disable.

1: Enable

0

SCI_EN (System Control Interrupt Enable). Globally selects power management events (PMEs) reported in PM1A_STS
and GPE0_STS (F1BAR1+I/O Offset 08h and 10h) to be either an SCI or SMI type of interrupt.

0: APM Mode, generates an SMI and status is reported at F1BAR0+I/O Offset 00h/02h[0].

1: ACPI Mode, generates an SCI if the corresponding PME enable bit is set and status is reported at F1BAR1+I/O Offset

08h and 10h.

Note:

This bit enables the ACPI state machine.

Offset 0Eh

ACPI_BIOS_STS Register (R/W)

Reset Value: 00h

7:1

Reserved. Must be set to 0.

0

BIOS_STS (BIOS Status Release). When 1 is written to the GLB_RLS bit (F1BAR1+I/O Offset 0Ch[2]), this bit is also set
to 1.

Write 1 to clear.

Offset 0Fh

ACPI_BIOS_EN Register (R/W)

Reset Value: 00h

7:2

Reserved. Must be set to 0.

1

BIOS_RLS (BIOS Release). (Write Only) When this bit is asserted, allow the BIOS to release control of the global lock.

0: Disable.

1: Enable.

This is a write only bit and reads of this bit always return a 0.

To generate an SCI, the BIOS writes the BIOS_RLS bit which in turn sets the GBL_STS bit (F1BAR1+I/O Offset 08h[5]) and
raises a PME. For the PME to generate an SCI, set GBL_EN (F1BAR1+I/O Offset 0Ah[5] to 1).

Table 6-34. F1BAR1+I/O Offset: ACPI Support Registers (Continued)

Bit

Description

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