DFI OT905-B series - Manual (Page 25)

www.dfi .com Chapter 3 Hardware Installation
25
Chapter 3
Signal Pin# Pin Type Pwr Rail /Tolerance PU/PD Description
SPI_CS# B97 O CMOS 3.3V Suspend/3.3V Chip select for Carrier Board SPI - may be sourced from chipset SPI0 or SPI1
SPI_MISO A92 I CMOS 3.3V Suspend/3.3V Data in to Module from Carrier SPI
SPI_MOSI A95 O CMOS 3.3V Suspend/3.3V Data out from Module to Carrier SPI
SPI_CLK A94 O CMOS 3.3V Suspend/3.3V Clock from Module to Carrier SPI
SPI_POWER A91 O 3.3V Suspend/3.3V
Power supply for Carrier Board SPI – sourced from Module – nominally
3.3V. The Module shall provide a minimum of 100mA on SPI_POWER.
Carriers shall use less than 100mA of SPI_POWER. SPI_POWER
shall only be used to power SPI devices on the Carrier
BIOS_DIS0# A34
BIOS_DIS1# B88
Signal Pin# Pin Type Pwr Rail /Tolerance PU/PD Description
VGA_RED B89 O Analog Analog PD 150 to Gnd Red for monitor. Analog output
VGA_GRN B91 O Analog Analog PD 150 to Gnd Green for monitor. Analog output
VGA_BLU B92 O Analog Analog PD 150 to Gnd 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 PU 2.2KW 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 PU 2.2KW to 3.3V DDC data line.
Signal Pin# Pin Type Pwr Rail /Tolerance PU/PD Description
I2C_CK B33 I/O OD CMOS 3.3V Suspend/3.3V PU 2.2KW to 3.3VSB General purpose I2C port clock output
I2C_DAT B34 I/O OD CMOS 3.3V Suspend/3.3V PU 2.2KW to 3.3VSB General purpose I2C port data I/O line
Signal Pin# Pin Type Pwr Rail /Tolerance PU/PD Description
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.
KBD_RST# A86 I CMOS 3.3V / 3.3V PU 8.2K to 3.3V
Input to Module from (optional) external keyboard controller that can force a reset. Pulled high on the Module. This is a legacy
artifact of the PC-AT.
KBD_A20GATE A87 I CMOS 3.3V / 3.3V PU 8.2K to 3.3V
Input to Module from (optional) external keyboard controller that can be used to control the CPU A20 gate line. The A20GATE
restricts the memory access to the bottom megabyte and is a legacy artifact of the PC-AT.Pulled high on the Module.
SPI Signals Descriptions
I CMOS NA
Selection straps to determine the BIOS boot device.
The Carrier should only float these or pull them low, please refer to
COM Express Module Base Specification Revision 2.1 for strapping options of BIOS disable signals.
VGA Signals Descriptions
I2C BUS Signal Descriptions
Miscellaneous Signal Descriptions