Hardware Reference
In-Depth Information
programmed, you should put a sticker over the window to protect it.
EEPROM/Flash ROM
A more advanced 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 erased and
reprogrammed directly in the circuit board they are installed in, with no special 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 opening the system chassis.
With a flash ROM or EEPROM, you don't need a UV eraser or device programmer to program or
erase chips. Virtually all PC motherboards built since 1994 use flash ROMs or EEPROMs, as do
most other computer devices with firmware..
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 can easily upgrade the motherboard ROM without having to swap chips. In most cases,
you download the updated ROM from the motherboard 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.
For more information on updating your PC motherboard flash ROMs, see the section in this
chapter, “
Upgrading the BIOS
,
”
p.
274
.
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
so easy and inexpensive, vehicle manufacturers are releasing bug-fix ROM upgrades that
correct operational problems or improve vehicle performance. In most cases, you must check
with your dealer to see whether any new vehicle ROMs are available. If you have a GM car,
GM has a website where you can get information about the BIOS revisions available for your
car, which it calls Vehicle Calibrations. The GM Vehicle Calibration Information site address
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.
Flash ROM updates can also be used to add new capabilities to existing peripherals or devices—for
example, updating an HD video camera to support higher capacity SDXC flash storage or updating
optical rewritable drives to support new media.
These days, many objects with embedded computers controlling them are using flash ROMs; for
example, I have updated the flash ROM code (often called
firmware
) in hard drives, solid-state
