Power Management Interface Signals - AMD Geode SC3200 Data Book

32581C
3.4.15

Power Management Interface Signals

Signal Name Ball No.
CLK32 AH8
GPWIO0 AH6
GPWIO1 AK5
GPWIO2 AJ6
LED# AL4
ONCTL# AJ5
PWRBTN# AH5
PWRCNT1 AK6
PWRCNT2 AL7
THRM# AK4
64
Type Description
O 32.768 KHz Output Clock
I/O General Purpose Wakeup I/Os. These signals each
have an internal pull-up of 100 KΩ.
O LED Control. Drives an externally connected LED (on,
off or a 1 Hz blink). Sleeping / Working indicator. This sig-
nal is an open-drain output.
O On / Off Control. This signal indicates to the main power
supply that power should be turned on. This signal is an
open-drain output.
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 222).
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.
O Suspend Power Plane Control 1 and 2. Control signal
asserted during power management Suspend states.
O
These signals are open-drain outputs.
I Thermal Event. Active low signal generated by external
hardware indicating that the system temperature is too
high.
Signal Definitions
AMD Geode™ SC3200 Processor Data Book
Mux
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