ADLINK LittleBoard 735 - Manual (Page 36)

Chapter 3 Hardware
30 Reference Manual LittleBoard 735
Utility 1 Interface
The Utility 1 (J15) interface routes various signals to devices such as keyboard, speaker, battery, power-on
LED, and reset switch.
Table 3-7 defines the pin signals for the J15, Utility 1 header, which consists of 16
pins, 2 rows, odd/even (1, 2) sequence with 0.100" (2.54mm) pitch and provides the following functions.
Keyboard
The signal lines for a PS/2 keyboard are provided through the Utility 1 interface, which is also fully PC/AT
compatible.
External Battery
An external battery input connection is provided through the Utility 1 interface as well as the J35 header to
support the Real Time Clock in the event the on-board battery is not used.
Power-On LED
The power-on LED signal provides +3.3 volts power for an external LED that indicates the system is
powered on.
Reset Switch
The signal lines for a reset switch are provided through the Utility 1 interface as well as through the J46
Power Button header.
Speaker
The signal lines for a speaker port with 0.1-watt drive are provided through the Utility 1 interface.
NOTE To perform the equivalent of a power-on reset, the reset button must be pressed
and held for a minimum of four seconds.
Table 3-7. Utility 1 Interface Pin Signals (J15)
Pin # Signal I/O Description
1 NC - Not connected (-12V Power)
2 GND - Ground
3 NC - Not connected (-5V Power)
4 GND - Ground
5 LED O Power-On LED – This on-board +3.3 volts is provided through 330 ohm
resistor to an external Power-On LED.
6 NC - Not connected (Power Good)
7 SPKR+ O + Speaker Output – This signal drives external PC "Beep" speaker.
8 GND - Ground
9 RSTSW* I/O Reset Switch – This signal is provided for an external reset switch.
10 NC - Not connected (Keyboard Switch)
11 KBDATA I/O Keyboard Data – Data signal provided to external keyboard connector.
12 KBCLK I/O Keyboard Clock – Clock signal provided to external keyboard connector.
13 GND - Keyboard Ground
14 KBDPWR - Keyboard Power – This +5 volts is provided to external keyboard
connector. Requires external fuse for keyboard/mouse protection.