Specifications

Chapter 3 Hardware
46 Reference Manual LittleBoard 800
Speaker
The signal lines for a speaker port with 0.1-watt drive are provided through a Utility 1 interface (J15).
Table 3-16. Utility 1 Interface Pin/Signal Descriptions (J15)
Pin # Signal I/O Description
1 -12V I -12 Volts – Supplied from external power source.
2 GND I Ground
3 -5V I -5 Volts – Supplied from external power source.
4 GND I Ground
5 PwrLED 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 I Ground
9 RSTSW* I Reset Switch – This signal (ground) provided from 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 I Keyboard Ground
14 KBDPWR O Keyboard Power – This +5 volts is provided to external keyboard
connector. Requires external fuse for keyboard/mouse protection.
15 BATV+ I
Backup Battery – This connection provides an additional backup battery
from an external source. It can also be used in place of the on-board
backup battery, B1, shipped with all LittleBoard 800s. Each RTS battery
input is protected with a zener diode.
16 BATV- I Battery - Return (Grounded)
Notes: The shaded area denotes power or ground. The signals marked with * = Negative true logic.
Utility 2 Interface (J13)
The Utility 2 interface consists of a 24-pin connector used to interface various signals to the external
board with external connections, or directly to the respective connector such as, the mouse, USB, etc.
Table 3-18 gives the pin-outs and interface signals for the Utility 2 interface and it has 24 pins, 2 rows,
odd/even, (1, 2) with 0.100” pin spacing.
• PS/2 Mouse signals
• Infrared (IrDA) signals
• SMBus signals
• USB signals for USB ports 1 and 2
• Power button signal
System Management Bus (SMBus)
The I/O Hub, 82801DBM, (Southbridge) contains both a host and slave SMBus port; but the host cannot
access the slave internally. The slave port allows an external master access to the I/O Hub through the
connector (J13). The master contained in the 82801DBM is used to communicate with the SDRAM
DDR DIMM, 82541(GI/PI) Gigabit Ethernet controller, and the clock generator. Table 3-17 gives the
addresses for these devices with the components and corresponding binary addresses of the SMBus.