Signal Definitions

32580B

3.4.15Power Management Interface Signals (Continued)

Signal Name

Ball No.

Type

Description

Mux

 

 

 

 

 

PWRBTN#

AH5

I

Power Button. Input used by the power management

---

 

 

 

logic to monitor external system events, most typically a

 

 

 

 

system on/off button or switch.

 

 

 

 

The signal has an internal pull-up of 100 KΩ, a Schmitt-

 

 

 

 

trigger input buffer and debounce protection of at least 16

 

 

 

 

ms.

 

 

 

 

ACPI is non-functional and all ACPI outputs are unde-

 

 

 

 

fined when the power-up sequence does not include

 

 

 

 

using the power button. SUSP# is an internal signal gen-

 

 

 

 

erated from the ACPI block. Without an ACPI reset,

 

 

 

 

SUSP# can be permanently asserted. If the USE_SUSP

 

 

 

 

bit in CCR2 of GX1 module is enabled (Index C2h[7] = 1),

 

 

 

 

the CPU will stop.

 

 

 

 

If ACPI functionality is desired, or the situation described

 

 

 

 

above avoided, the power button must be toggled. This

 

 

 

 

can be done externally or internally. GPIO63 is internally

 

 

 

 

connected to PWRBTN#. To toggle the power button with

 

 

 

 

software, GPIO63 must be programmed as an output

 

 

 

 

using the normal GPIO programming protocol (see Sec-

 

 

 

 

tion 6.4.1.1 "GPIO Support Registers" on page 233).

 

 

 

 

GPIO63 must be pulsed low for at least 16 ms and not

 

 

 

 

more than 4 sec.

 

 

 

 

Asserting POR# has no effect on ACPI. If POR# is

 

 

 

 

asserted and ACPI was active prior to POR#, then ACPI

 

 

 

 

will remain active after POR#. Therefore, BIOS must

 

 

 

 

ensure that ACPI is inactive before GPIO63 is pulsed

 

 

 

 

low.

 

 

 

 

 

 

PWRCNT1

AK6

O

Suspend Power Plane Control 1 and 2. Control signal

---

 

 

 

asserted during power management Suspend states.

 

PWRCNT2

AL7

O

---

These signals are open-drain outputs.

 

 

 

 

 

 

 

 

 

THRM#

AK4

I

Thermal Event. Active low signal generated by external

---

 

 

 

hardware indicating that the system temperature is too

 

 

 

 

high.

 

 

 

 

 

 

AMD Geode™ SC2200 Processor Data Book

69

Page 65
Image 65
AMD SC2200 manual PWRBTN# AH5, PWRCNT1 AK6, Suspend Power Plane Control 1 and 2. Control signal, PWRCNT2 AL7, THRM# AK4