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Chapter 3 Hardware Installation
23
Chapter 3
Signal
Pin#
Pin Type
Pwr Rail /Tolerance
PU/PD
Description
VGA_RED
B89
O Analog
Analog
PD 150R
Red for monitor. Analog output
VGA_GRN
B91
O Analog
Analog
PD 150R
Green for monitor. Analog output
VGA_BLU
B92
O Analog
Analog
PD 150R
Blue for monitor. Analog output
VGA_HSYNC
B93
O CMOS
3.3V / 3.3V
Horizontal sync output to VGA monitor
VGA_VSYNC
B94
O CMOS
3.3V / 3.3V
Vertical sync output to VGA monitor
VGA_I2C_CK
B95
I/O OD CMOS 3.3V / 3.3V
PD 2.2K to 3.3V
DDC clock line (I2C port dedicated to identify VGA monitor capabilities)
VGA_I2C_DAT
B96
I/O OD CMOS 3.3V / 3.3V
PD 2.2K to 3.3V
DDC data line.
Signal
Pin#
Pin Type
Pwr Rail /Tolerance
PU/PD
Description
SER0_TX
A98
O CMOS
3.3V~5V
General purpose serial port 0 transmitter
SER0_RX
A99
I CMOS
3.3V~5V
General purpose serial port 0 receiver
SER1_TX
A101
O CMOS
3.3V~5V
General purpose serial port 1 transmitter
SER1_RX
A102
I CMOS
3.3V~5V
General purpose serial port 1 receiver
Signal
Pin#
Pin Type
Pwr Rail /Tolerance
PU/PD
Description
I2C_CK
B33
I/O OD CMOS 3.3V Suspend/3.3V
PU 2.2K to 3.3VSB
General purpose I2C port clock output
I2C_DAT
B34
I/O OD CMOS 3.3V Suspend/3.3V
PU 2.2K to 3.3VSB
General purpose I2C port data I/O line
SPKR
B32
O CMOS
3.3V / 3.3V
Output for audio enunciator - the "speaker" in PC-AT systems.
This port provides the PC beep signal and is mostly intended for
debugging purposes.
WDT
B27
O CMOS
3.3V / 3.3V
Output indicating that a watchdog time-out event has occurred.
FAN_PWNOUT
B101
O OD CMOS
3.3V / 12V
Fan speed control. Uses the Pulse Width Modulation (PWM) technique to control the fan's RPM.
FAN_TACHIN
B102
I OD CMOS
3.3V / 12V
PU 10K to 3.3V
Fan tachometer input for a fan with a two pulse output.
TPM_PP
A96
I CMOS
3.3V / 3.3V
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.
VGA Signals Descriptions
Serial Interface Signals Descriptions
Miscellaneous Signal Descriptions