Specifications

Chapter 3 Hardware
36 Reference Manual LittleBoard 735
Miscellaneous
Real Time Clock (RTC)
The LittleBoard 735 contains a Real Time Clock (RTC). The BIOS (CMOS) RAM is backed up with a
Lithium Battery. If the battery is not present, the BIOS has a battery-free boot option to complete the boot
process.
Temperature Monitoring
The Intel Atom processor supports the THERMTRIP# signal for catastrophic thermal protection. The
THERMTRIP# is an open drain signal from the processor which is used to shut down the processor core
voltage. This signal is connected to the THERMTRIP# input signal and indicates that a thermal trip from the
processor occurred and the ICH7-M will immediately transition to the S5 state.
User GPIO Signals
The LittleBoard 735 provides GPIO pins for custom use. The signals are routed to the J40 header, and the
Enable and Initialize values are set in the BIOS. An example of how to use the GPIO pins resides in the
Miscellaneous Source Code Examples on the LittleBoard 735 Support Software QuickDrive
TM
.
The example program can be built by using the make.bat file. This produces a 16-bit DOS executable
application, gpio.exe, which can be run on the LittleBoard 735 to demonstrate the use of GPIO pins. For
more information about the GPIO pin operation, refer to the Programming Manuals for the Southbridge
(82801GBM) and Super I/O (SCH3114I-NU) controllers at:
http://www.intel.com/assets/pdf/datasheet/307013.pdf
http://www.smsc.com/main/catalog/sch311x.html
Table 3-20 lists the pin signals for the J40 GPIO header, which uses 10 pins, two rows, odd/even sequence
with 0.079" (2mm) pitch.
Note: The shaded areas denote power or ground.
NOTE The LittleBoard 735 requires a heatsink for the Atom N270 processor.
Table 3-20. User GPIO Pin/Signal Descriptions (J40)
Pin # Signal Description
1
VCC +3.3 Volts DC +/ 5%
2 GND Ground
3 GPI0 User defined
4 GPO0 User defined
5 GPI1 User defined
6 GPO1 User defined
7 GPI2 User defined
8 GPO2 User defined
9 GPI3 User defined
10 GPO3 User defined