Appendix A
Frequently Asked Question
Note: FAQ may be updated without notice. If you
cannot find the information that you need in this
appendix, visit our WWW home page, (address:
http://www.aopen.com.tw) and check the FAQ
area and other new information.
Q: How can I identify the mainboard BIOS version?
A: The AOpen mainboard BIOS version appears on the upper-left corner of the
POST (Power-On Self Test) screen. Normally, it starts with R and is found in
between the model name and the date. For example:
AP53/AX53 R3.80 Oct.22.1996
Q: How can I identify the model name & revision of the mainboard from
PCB?
A: The AOpen mainboard revision appears as REV:X.X on the PCB, usually it is
under beneath of AOpen Logo & mainboard model name. For example,
“AX6L REV:1.2” shall appear on the PCB as follows:
AX6L
REV:1.2
A-1
Frequently Asked Questions
Q: What is MMX?
A: MMX is the new single-line multiple-instruction technology of the new Intel
Pentium PP/MT (P55C) and Pentium II (Klamath) CPU. The AMD K6 and
Cyrix M2 will support MMX, too. The MMX instructions are specifically useful
for multimedia applications (such as 3D video, 3D sound, video conference).
The performance can be improved if applications use these instructions. All
AOpen MBs have at least dual power onboard to support MMX. It is not
necessary to have special chipset for MMX CPU.
Q: What is USB (Universal Serial Bus)?
A: USB is a new 4-pin serial peripheral bus that is capable of cascading
low/medium speed peripherals (less than 10Mbit/s) such as keyboard, mouse,
joystick, scanner, printer and modem/ISDN. With USB, the traditional
complex cables from back panel of your PC can be eliminated.
You need the USB driver to support USB device(s). AOpen MBs are all USB
ready, you may get latest BIOS from AOpen web site
(http://www.aopen.com.tw). Our latest BIOS includes the keyboard driver
(called Legacy mode), that simulates USB keyboard to act as AT or PS/2
keyboard and makes it possible to use USB keyboard if you don't have driver
in your OS. For other USB devices, you may get the drivers from your device
vendor or from OS (such as Win95). Be sure to turn off "USB Legacy
Support" in BIOS "Chipset Setup" if you have another driver in your OS.
Q: What is FCC DoC (Declaration of Conformity)?
A: The DoC is new certification standard of FCC regulations. This new standard
allows DIY component (such as mainboard) to apply DoC label separately
without a shielding of housing. The rule to test mainboard for DoC is to
remove housing and test it with regulation 47 CFR 15.31. The DoC test of
mainboard is more difficult than traditional FCC test. If the mainboard passes
DoC test, that means it has very low EMI radiation and you can use any kind
of housing (even paper housing). Following is an example of DoC label.
AP5T
Test To Comply
With FCC Standards
FOR HOME OR OFFICE USE
A-2
Frequently Asked Questions
Q: What is Bus Master IDE (DMA mode)?
A: The traditional PIO (Programmable I/O) IDE requires the CPU to involve in all
the activities of the IDE access including waiting for the mechanical events.
To reduce the workload of the CPU, the bus master IDE device transfers data
from/to memory without interrupting CPU, and releases CPU to operate
concurrently while data is transferring between memory and IDE device. You
need the bus master IDE driver and the bus master IDE HDD to support bus
master IDE mode. Note that it is different with master/slave mode of the IDE
device connection. For more details, refer to section 2.3 "Connectors".
Q: What is the Ultra DMA/33?
A: This is the new specification to improve IDE HDD data transfer rate. Unlike
traditional PIO mode, which only uses the rising edge of IDE command signal
to transfer data, the DMA/33 uses both rising edge and falling edge. Hence,
the data transfer rate is double of the PIO mode 4 or DMA mode 2. (16.6MB/s
x2 = 33MB/s).
The following table lists the transfer rate of IDE PIO and DMA modes. The
IDE bus is 16-bit, which means every transfer is two bytes.
Mode Clock per
33MHz
PCI
PIO mode 0 30ns 20 600ns (1/600ns) x 2byte = 3.3MB/s
PIO mode 1 30ns 13 383ns (1/383ns) x 2byte = 5.2MB/s
PIO mode 2 30ns 8 240ns (1/240ns) x 2byte = 8.3MB/s
PIO mode 3 30ns 6 180ns (1/180ns) x 2byte = 11.1MB/s
PIO mode 4 30ns 4 120ns (1/120ns) x 2byte = 16.6MB/s
DMA mode 0 30ns 16 480ns (1/480ns) x 2byte = 4.16MB/s
DMA mode 1 30ns 5 150ns (1/150ns) x 2byte = 13.3MB/s
DMA mode 2 30ns 4 120ns (1/120ns) x 2byte = 16.6MB/s
DMA/33
Q: What is ACPI (Advanced Configuration & Power Interface) and OnNow?
A: The ACPI is new power management specification of 1997 (PC97). It intends
to save more power by taking full control of power management to operating
system and not through BIOS. Because of this, the chipset or super I/O chip
needs to provide standard register interface to OS (such as Win97) and
provides the ability for OS to shutdown and resume power of different part of
chip. The idea is a bit similar to the PnP register interface.
30ns 4 120ns (1/120ns) x 2byte x2 = 33MB/s
Clock
count
Cycle
time
Data Transfer rate
A-3