SC2200 NSC [National Semiconductor], SC2200 Datasheet - Page 253

• Manufacturer Part Number: SC2200
• Description: Thin Client On a Chip
• Manufacturer: NSC [National Semiconductor]

Revision 3.0
Core Logic Module
5.4.2.2
F1 Index 40h, Base Address Register 1 (F1BAR1), points
to the base address of where the ACPI Support registers
Offset 00h-03h
Offset 04h
Note:
Offset 05h
Offset 06h
Offset 07h
31:5
2:0
7:0
7:0
7:6
2:1
Bit
4
3
5
4
3
This register should not be read. It controls a reserved function of power management logic.
ACPI Support Registers
Description
Reserved. Always reads 0.
THT_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:
1:
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].
Reserved. Always reads 0.
CLK_VAL (Clock Throttling Value). CPU duty cycle:
000: Reserved
001: 12.5%
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].
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].
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)
Reserved. Must be set to 0.
INTR_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.
GPWIO_DBNC_DIS (GPWIO0 and GPWIO1 Debouncers). Debounce settings for GPWIO0 and GPWIO1. Selects the
time that a high-to-low or low-to-high transition (debounce period) must be for GPWIO0 to be recognized.
0: Debounce period is 15.8 msec. (Default)
1: Debounce period is 31 µs.
GPWIO2 pin is fixed at 31 µs.
Reserved. Must be set to 0.
Disable.
Enable.
Table 5-34. F1BAR1+I/O Offset: ACPI Support Registers
(Continued)
ACPI_FUN_CNT — ACPI Function Control Register (R/W)
SMI_CMD — OS/BIOS Requests Register (R/W)
P_LVL3 — Enter C3 Power State Register (RO)
P_CNT — Processor Control Register (R/W)
010: 25%
011: 37.5%
Reserved
253
are located. Table 5-34 shows the I/O mapped ACPI Sup-
port registers accessed through F1BAR1.
100: 50%
101: 62.5%
110: 75%
111: 87.5%
Reset Value: 00000000h
Reset Value: 00h
Reset Value: xxh
Reset Value: 00h
Reset Value: 00h
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