
VT8231
Preliminary Revision 0.8
October 29, 1999
-27-
Pinouts
7HFKQRORJLHV,QF
:H &RQQHFW
Resets, Clocks, and Clock Control
Signal Name
Pin #
I/O
Signal Description
PWRGD
PWRBTN#
E3
U2
I
I
Power Good.
Connected to the PWRGOOD signal on the Power Supply.
Power Button.
Used by the Power Management subsystem to monitor an
external system on/off button or switch. The VT8231 performs a 200us
debounce of this input if Function 4 Rx40[5] is set to 1. (3.3V only)
Sleep Button.
Used by the power management subsystem to monitor an
external system sleep button or switch (Function 4 Rx40[6] = 1). Connect to
VCC if not used.
PCI Reset.
Active low reset signal for the PCI bus. The VT8231 will assert
this pin during power-up or from the control register.
RTC Crystal Input
: 32.768 KHz crystal or oscillator input. This input is
used for the internal RTC and for power-well power management logic.
RTC Crystal Output
: 32.768 KHz crystal output
Oscillator.
14.31818 MHz clock signal used by the internal Timer.
Slow Clock.
Frequency selectable if PMU function 4 Rx54[1-0] is nonzero
(set to 01, 10, or 11).
CPU Clock Stop
(Rx75[4] = 0). Signals the system clock generator to
disable the CPU clock outputs. Not connected if not used. See also PMU I/O
Rx2C[3].
PCI Clock Stop
(Rx75[5] = 0). Signals the system clock generator to disable
the PCI clock outputs. Not connected if not used.
SLPBTN#
/
FAN2 /
GPIO18
PCIRST#
K3
I / I
/ IO
E4
O
RTCX1
E2
I
RTCX2
OSC
SLOWCLK
/
GPO0
CPUSTP#
/
GPO5
E1
T12
R4
O
I
O
W2
O /
O
PCISTP#
/
GPO6
W1
O /
O