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3.3.12.
Miscellaneous
Signal
Pin # Description
I/O
PU/PD
Comment
SPKR
B32
Output for audio enunciator, the “speaker” in PC-AT
systems
O 3.3V
WDT
B27
Output indicating that a watchdog time-out event has
occurred.
O 3.3V
THRM#
B35
Input from off-module temp sensor indicating an over-
temp situation.
I 3.3V
THERMTRIP#
A35
Active low output indicating that the CPU has entered
thermal shutdown.
O 3.3V
PU 330 ohm 3.3V
FAN_PWMOUT B101 Fan speed control. Uses the Pulse Width Modulation
(PWM) technique to control the fan’s RPM.
O OD 3.3V
PU 2.2K 3.3V
FAN_TACHIN11
B102 Fan tachometer input for a fan with a two pulse output.
I OD 3.3V
PU 10k 3.3V
TPM_PP11
C83
Trusted Platform Module (TPM) Physical Presence pin.
Active high. TPM chip has an internal pull down. This
signal is used to indicate Physical Presence to the
TPM.
I 3.3V
PD 10k 3.3V
PD is only placed
when TPM is
installed on module
3.3.13.
SMBus
Signal
Pin # Description
I/O
PU/PD
Comment
SMB_CK
B13
System Management Bus bidirectional clock line.
Power sourced through 5V standby rail and main power
rails.
I/O OD 3.3VSB
PU 8k2 3.3VSB
SMB_DAT#
B14
System Management Bus bidirectional data line. Power
sourced through 5V standby rail and main power rails.
I/O OD 3.3VSB
PU 8k2 3.3VSB
SMB_ALERT#
B15
System Management Bus Alert – active low input can
be used to generate an SMI# (System Management
Interrupt) or to wake the system. Power sourced
through 5V standby rail and main power rails.
I 3.3VSB
PU 10k 3.3VSB
3.3.14.
I2C Bus
Signal
Pin # Description
I/O
PU/PD
Comment
I2C_CK
B33
General purpose I²C port clock output/input
I/O OD 3.3VSB
PU 2k2 3.3VSB
I2C_DAT
B34
General purpose I²C port data I/O line
I/O OD 3.3VSB
PU 2k2 3.3VSB
3.3.15.
General Purpose I/O (GPIO)
Signal
Pin # Description
I/O
PU/PD
Comment
GPO[0]
A93
General purpose output pins.
O 3.3V
PU 10K 3.3V
After hardware
RESET output low
GPO[1]
B54
General purpose output pins.
O 3.3V
PU 10K 3.3V
After hardware
RESET output low
GPO[2]
B57
General purpose output pins.
O 3.3V
PU 10K 3.3V
After hardware
RESET output low
