Express-BD7
Pinouts and Signal Descriptions
17
3.3.9. Miscellaneous
Signal
Pin
Description
I/O
PU/PD
Comment
SPKR B32
Output for audio enunciator, the “speaker” in
PC-AT systems
O 3.3V
PU 1k 3.3V Platform
specification
WDT B27
Output indicating that a watchdog time-out
event has occurred.
O 3.3V
PU 10k
3.3V
THRM# B35
Input from off-module temp sensor indicating an
over-temp situation.
I 3.3VSB
THRMTRIP# A35
Active low output indicating that the CPU has
entered thermal shutdown.
O 3.3V
PU 10k
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_TACHIN B102
Fan tachometer input for a fan with a two pulse
output.
I OD 3.3V
PU 47K
3.3V
TPM_PP
A96 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 100k
3.3V
PD only when TPM
on module
3.3.10. 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 2.2k
3.3VSB
Equivalent resistor
is 2.2k
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 2.2k
3.3VSB
Equivalent resistor
is 2.2k
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
3.3.11. 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 2.2K
3.3VSB
Source SEMA BMC
I2C_DAT
B34
General purpose I²C port data I/O line
I/O OD
3.3VSB
PU 2.2K
3.3VSB
Source SEMA BMC
