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Chapter 3
Table 3-7. Utility 1 Interface Pin Signals (J15) (Continued)
15
BATV+
16
BATV-
Note: The shaded table cells denote power or ground. The * symbol indicates the signal is Active Low.
Utility 2 Interface
The Utility 2 (J13) interface routes various signals to devices such as a mouse or power button.
defines the pin signals of the J13, Utility 2 interface header, which consists of 24 pins, 2 rows, odd/even (1,
2) pin sequence with 0.100" (2.54mm) pitch and provides the following functions.
System Management Bus (SMBus)
The ICH7-M, I/O Hub, 82801GBM (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
Utility 2 header (J13) as well as the J45 SMBus header. The master contained in the 82801GBM is used to
communicate with the DDR2 SODIMM and the clock generator.
addresses of these devices on the SMBus.
Table 3-8. SMBus Reserved Addresses
Component
DDR2 SODIMM
Clock Generator (9LPRS501)
I/O Hub (82801GBM)
Mouse
The signal lines for a PS/2 mouse are provided through the Utility 2 interface (J13).
Power Button
A power button can be connected to the board through the Utility 2 interface as well as through the J46
Power Button header. Press and hold the green button on the power button cable for at least four seconds to
power off the system. To power on the system, press and release the green button and wait for the system to
boot.
Table 3-9.
Utility 2 Interface Pin Signals (J13)
Pin # Signal
1
NC
2
PWRBT*
3
BATLOW*
4
NC
5
NC
6
NC
7
GND
8
VCC
9
MDATA
LittleBoard 735
-
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 735s. Each RTS battery
input is protected with a zener diode.
-
Battery - Return (Grounded)
Address Binary
1010,000x
1101,001x
0000,000x
I/O
Description
-
Not connected (Lid Switch)
I
Power Button – This signal allows the user to turn off and on the power
supply from an external switch.
I
Battery Low – This signal from an external battery indicates to the I/O
Hub there is insufficient power to boot the system.
-
Not connected (IR Mode select)
-
Not connected (IR Transmit Data)
-
Not connected (IR Receive Data)
-
Ground
-
+5 Volts
I/O
Mouse Data – Data signal provided to external mouse connector.
Reference Manual
Table 3-8
lists the corresponding binary
b
b
(default) Programmable Master
b
Hardware
Table 3-9
31
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