User Guide

Frequently Asked Questions
B-14
jumper setting information is stored in CMOS, if the battery is lost or BIOS setup
is accidentally changed, end user (or distributor) may need to open the housing
and check the CPU again.
Most of all, you need a start voltage to boot CPU and go into BIOS for
jumperless setting. 2.85V may be OK for P55C and K6-166, but minimum
voltage of K6-233MHz is 3.1V, it can not boot if user plugs K6-233 onto current
jumperless mainboard.
We probably need to wait after the mature of SMbus, if CPU and clock
generator and other ICs are all SMbus compliance. Chipset can then detect and
report the system configuration right after power on. Then we can have true
jumperless mainboard.
Q: What is the difference of Synchronous and Asynchronous Switching
Regulator?
A: Switching regulator turns on/off Power FET with very high frequency and uses
L/C charge and discharge circuit to do voltage drop. Most of the current
switching designs are Asynchronous mode, which from the technical point of
view, uses Schottky diode for current loop back when power FET is off, and still
consumes very high power as well as heat. AOpen AP5T-3/AX5T-3 implement
high efficient Synchronous switching design that uses MOS FET for the current
loop back and synchronous with the major Power FET (One is on, the other will
be off.). The temperature is less than 36 degree C compared with 57 degree of
Asynchronous design.
Q: What is RTC Wake Up Timer (Alarm)?
A: RTC (Real Time Clock) is a device like electronic watch, and keep the date/time
of the computer system running. The Wake Up Timer is more like an alarm,
which wakes up and powers on your system at a pre-defined time for specific
application. It can be set to wake up everyday or on specific date within a month.
The date/time accurate is second. To set the date/time, go into BIOS setup,
Power Management RTC Wake Up Timer, select Enable. RTC is a standard
device of all the mainboard, but Wake Up Timer is not a standard design,
AOpen AX5T/AX58 support RTC Wake Up Timer.