System Logic; Power Subsystem; Power Rails; Rtc Back-Up Battery - CompuLab SBC-FITPC3 Reference Manual

4

SYSTEM LOGIC

4.1

Power Subsystem

4.1.1

Power Rails

The Fit-PC3 is powered with a single 12V power supply.
Table 4
Signal Name
VIN_12V
GND
4.1.2

RTC Back-Up Battery

The Fit-PC3 features an on-board 18mAh rechargeable coin cell lithium battery, which maintains the
Fit-PC3 RTC when the main power supply is not present. The battery is being re-charged whenever
Fit-PC3 is connected to the main power supply. The back-up battery will sustain the RTC for up to 6
months with no charging.
4.1.3

Power-on Logic

The Fit-PC3 is designed to support standard PC power-on logic. The Fit-PC3 BIOS can be configured
for the following behavior for when main power is applied:
·
Stay off
·
Turn on automatically
·
Preserve the last state before power disconnect
4.1.4

Power Button

The Fit-PC3 power button SW2 controls the system power state. The button serves as a standard
ON/OFF button in a typical PC system. The button behavior is programmable using standard tools
available in MS Windows and Linux.
Revised December 2011
Power signals
Type
P Main power supply. Typical voltage – 12V.
P Common ground.
SBC-FITPC3
Description
System Logic
14