ADLINK Technology COM Express cExpress-BT2, Руководство пользователя

Страница: 26 / 88

20
Pinouts and Signal Descriptions
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
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
FAN_TACHIN B102 Fan tachometer input for a fan with a two pulse
output.
I OD 3.3V PU 10k
3.3V
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 2k2
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 2k2
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