Hardware Reference
In-Depth Information
EEPROM/Flash ROM
A newer type of ROM is the EEPROM, which stands for
electrically erasable PROM
.
These chips are also called
flash ROMs
and are characterized by their capability to be
erasedandreprogrammeddirectlyinthecircuitboardtheyareinstalledin,withnospecial
equipment required. By using an EEPROM, or flash ROM, you can erase and reprogram
the motherboard ROM in a PC without removing the chip from the system or even open-
ing the system chassis.
With a flash ROM or EEPROM, you don't need a UV eraser or device programmer to
program or erase chips. Not only do virtually all PC motherboards built since 1994 use
flash ROMs or EEPROMs, but most automobiles built since then use them as well.
The EEPROM or flash ROM can be identified by a 28xxxx or 29xxxx part number, as
well as by the absence of a window on the chip. Having an EEPROM or a flash ROM in
your PC motherboard means you now can easily upgrade the motherboard ROM without
having to swap chips. In most cases, you download the updated ROM from the mother-
board manufacturer's website and then run a special program it provides to update the
ROM. This procedure is described in more detail later in this chapter.
I recommend that you periodically check with your motherboard manufacturer to see
whether an updated BIOS is available for your system. An updated BIOS might contain
bug fixes or enable new features or device support not originally found in your system.
Non-PC ROM Upgrades
For the auto enthusiasts out there, you might want to do the same for your car; that is, check
to see whether ROM upgrades are available for your vehicle's computer. Now that updates
are soeasy and inexpensive, vehicle manufacturers are releasing bug-fix ROM upgrades that
correctoperationalproblemsorimprovevehicleperformance.Inmostcases,youmustcheck
with your dealer to see whether any new vehicle ROMs are available. If you have a GM car,
GMhasawebsitewhereyoucangetinformationabouttheBIOSrevisionsavailableforyour
car,whichitcallsVehicleCalibrations.TheGMVehicleCalibrationInformationsiteaddress
is
http://calid.gm.com
.
Besides updates from the vehicle manufacturer, some aftermarket companies produce ROM
upgrades for vehicles. If you are interested in having a custom program installed in your
flash ROM-equipped vehicle, I recommend Fastchip (
www.fastchip.com
)
, Hypertech
(
www.hypertech.com
)
, and Superchips (
www.superchips.com
). If you want to develop your
own vehicle calibrations, see
www.diy-efi.org
for more information.
