AMD 34. F1BAR1+I/O Offset Acpi Support Registers, AMD Geode SC2200 Processor Data Book 255

Core Logic Module - SMI Status and ACPI Registers - Function 1	32580B
6.4.2.2 ACPI Support Registers
F1 Index 40h, Base Address Register 1 (F1BAR1), points	are located. Table 6-34shows the I/O mapped ACPI Sup-
to the base address of where the ACPI Support registers	port registers accessed through F1BAR1.

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

Bit

Description

Offset 00h-03h		P_CNT — Processor Control Register (R/W)	Reset Value: 00000000h
31:5	Reserved. Always reads 0.

4THT_EN (Throttle Enable). When this bit is asserted, it enables throttling of the clock based on the CLK_VAL field (bits [2:0] of this register).

0:Disable.

1:Enable.

If F1BAR1+I/O Offset 18h[8] =1, an SMI is generated when this bit 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[1].

3	Reserved. Always reads 0.
2:0	CLK_VAL (Clock Throttling Value). CPU duty cycle:
	000: Reserved	010:	25%	100:	50%	110:	75%
	001: 12.5%	011:	37.5%	101:	62.5%	111:	87.5%

Offset 04h	Reserved	Reset Value: 00h
Note: This register should not be read. It controls a reserved function of power management logic.
Offset 05h	P_LVL3 — Enter C3 Power State Register (RO)	Reset Value: xxh

7:0

P_LVL3 (Power Level 3). Reading this 8-bit read only register causes the processor to enter the C3 power state. Reads of P_LVL3 return 0. Writes have no effect.

The ACPI state machine always waits for an SMI (any SMI) to be generated and serviced before transfer into C3 power state.

A read of this register causes an SMI if enabled: F1BAR1+I/O Offset 18h[11] = 1 (default).

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[4].

Offset 06h SMI_CMD — OS/BIOS Requests Register (R/W) Reset Value: 00h

7:0

SMI_CMD (SMI Command and OS / BIOS Requests). A write to this register stores data and a read returns the last data written. In addition, a write to this register always generates an SMI. A read of this register does not generate an SMI.

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[0].

Offset 07h	ACPI_FUN_CNT — ACPI Function Control Register (R/W)	Reset Value: 00h
7:6	LED_CNT (LED Output Control). Controls the blinking of an LED when in the SL4 or SL5 sleep state.
	00: Disable (LED# signal, is HIZ).
	01: Zero (LED# signal is HIZ).
	10: Blink @ 1 Hz rate, when in SL4 and SL5 sleep states. Duty cycle: LED# is 10% pulled low, 90% HIZ.
	11: One (LED# is pulled low, when in SL4 and SL5 sleep states).
5	Reserved. Must be set to 0.

4INTR_WU_SL1. Enables wakeup on enabled interrupts in sleep state SL1.

0:Disable wakeup from SL1, when an enabled interrupt is active.

1:Enable wakeup from SL1, when an enabled interrupt is active.

3GPWIO_DBNC_DIS (GPWIO0 and GPWIO1 Debounce). When enabled, a high-to-low or low-to-high transition of greater than 15.8 ms is required for GPWIO0 and GPWIO1 to be recognized.

0:Enable. (Default)

1:Disable. (No debounce)

	GPWIO2 pin does not have debounce capability.
2:1	Reserved. Must be set to 0.
AMD Geode™ SC2200 Processor Data Book		255