Table 3-12. Miscellaneous Signal Descriptions - Ampro COM 830 Reference Manual

Chapter 3
Table 3-11. TV-Out Signal Descriptions (Continued)
TV_DAC_B
TV_DAC_C

Table 3-12. Miscellaneous Signal Descriptions

Signal
I2C_CK
I2C_DAT
SPKR
BIOS_DISABLE
#
WDT
KBD_RST#
KBD_A20GATE
NOTE
Some signals have special functionality during the reset process. They may
bootstrap some basic important functions of the module.
For more information about this signal, please visit Ask an Expert on the Ampro
web site.
COM 830
TVDAC Channel B Output supports the
following: Composite video: not used
Component video: Luminance (Y) analog
signal.
S-Video: Luminance analog signal.
TVDAC Channel C Output supports the
following: Composite video: not used
Component: Chrominance (Pr) analog
signal.
S-Video: Chrominance analog signal.
Description
General purpose I ² C port clock output
General purpose I ² C port data I/O line
Output for audio enunciator, the "speaker" in
PC-AT systems
Module BIOS disable input. Pull low to disable
module BIOS. Used to allow off-module BIOS
implementations.
Output indicating that a watchdog time-out
event has occurred.
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.
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 low on
the module.
Reference Manual
Signals and Pinout Tables
O PD 150R
Analog
O PD 150R
Analog
I/O PU/PD Comment
O 3.3V PU 4k7
3.3V
I/O PU 4k7
3.3V 3.3V
O 3.3V SPEAKER
is a boot
strap signal
(see note 1
below)
I 3.3V PU 4k7
3.3V
I 3.3V PU 10k This signal
3.3V is not
supported
(see note 2
below)
I PU 10k
3.3V
I PU 10k
3.3V
Analog
output
Analog
output
33