
84
AMD Geode SC1200/SC1201 Processor Data Book
Signal Definitions
Revision 7.1
PWRBTN#
E29
AH5
I
Power Button. An input used by the power
management logic to monitor external sys-
tem events, most typically a system on/off
button or switch.
The signal has an internal pull-up of 100 K
,
a Schmitt-trigger input buffer and program-
mable debounce protection (F1BAR1+I/O
Offset 07h[0]) of at least 16 ms.
ACPI is non-functional and all ACPI outputs
are undefined when the power-up sequence
does not include using the power button.
SUSP# is an internal signal generated 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 situa-
tion described above avoided, the power but-
ton 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
Section244). 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
F31
AK6
O
Suspend Power Plane Control 1 and 2.
Control signal asserted during power man-
agement Suspend states. These signals are
open-drain outputs.
---
PWRCNT2
G31
AL7
O
---
THRM#
F28
AK4
I
Thermal Event. Active low signal generated
by external hardware indicating that the sys-
tem temperature is too high.
---
3.4.16
Power Management Interface Signals (Continued)
Signal Name
Ball No.
Type
Description
Mux
EBGA
TEPBGA