PROBURNER
Best EPROM burner on the market
Reviewed by IAN CHADWICKWhy burn your own chips? For one thing,
cartridge software loads and runs faster and easier. It also enables you
to customize your operating system to suit your special needs.
However, burning chips-EPROMS or EEPROMS-is not something
that most amateur programmers tackle. It's generally expensive, difficult
and unforgiving. Also, the variety of EPROMS that can be programmed by
most devices available is less than encouraging-too many are simply left
out for one reason or another.
The Thompson Electronics Proburner now changes
all that. It is an excellent buy for the versatility and ease of use that
it offers. This EPROM burner fits into the cartridge slot of an Atari XL
or XE computer. Control software is built in and so is the chip socket
itself (a low insertion-force socket rated for 10,000 insertions). There's
no need to hook up an 850 or load disk files first. But XE owners will
quickly come to hate their cartridge slots on the back of the computer,
since it makes chip insertion awkward and somewhat chancy.
The Proburner can read and write a wide range of 26-pin
and 28-pin chips from 2K to 16K, including the 2716, 2732, 2764 and 27128
EPROMs as well as the 2816A, 52B13, 52B23 and 52B33 EEPROMs. It can also
read 2K to 8K ROMs into memory and store the cartridge itself, using the
burner as its own tester to see if your efforts worked.
EPROM BASICS
EPROMs can be erased with a strong ultraviolet light. Many electronic
magazines have run stories explaining how to build an eraser using a medical
UV sterilizing lamp for under $25. EEPROMs can be erased electrically.
It's obviously easier, but EEPROM chips cost at least twice as much as
EPROMs.
EPROMS are not necessarily pin-compatible with your computer
or with the chips in your cartridges. (the OS ROM chip in the Atari XL/XE
series is a compatible 27128.) You can read these chips with the Proburner,
but you need a socket designed for an EPROM when you burn your code back
into such a chip. Many third-party cartridges use EPROMs- Monkey Wrench
and MAC/65, for example. Cannibalizing your unused carts is one simple
method of obtaining the sockets.
OPERATIONS
Proburner's selection of software commands is slim; load and save a
file to disk (using DOS, which overwrites code in low memory), cassette,
copy, burn-in, verify or run from chip, erase check and transfer to DOS.
There is also a monitor which can display, change, print or move a section
of memory.
There is no method of reading disk sectors, assembling
or disassembling memory-features I would prefer in-stead of the cassette
I/O. However, I found I could go to DOS and load my own monitor program
into low RAM. Then I could return to the cartridge and run It from there,
or jump to the cart from the monitor. This gives me the ability to disassemble
code before I try to change it.
The Proburner code itself takes up $8000 to $8FFF and
seems to be duplicated between $9000 and $9FFF. That's a 4K duplication
and, unless there is some good reason for it, the space could be better
used by a disassembling monitor or a miniassembler. Running the burner
from either start location seems to produce the same results. If the Proburner
wasn't so completely sealed in epoxy, I would take out the software chips
and reburn one of the duplicate areas with my own software instead.
FINER POINTS
Many factors must be considered before you try to burn a chip. I planned
to copy the XL/XE OS chip into RAM, save it to disk, delete the useless
self-test code, replace it with my monitor program, change the startup
colors, reverse the [OPTION] key toggle to activate BASIC when held down,
fix the printer timeout bug, tamper with the floating point routines-and
then write the whole 16K back into a 27128 chip.
However, Proburner saves memory to a disk file via the
DOS binary save command. And loading DOS writes DUP into memory-up to $3306.
So I over-wrote my carefully moved and edited ROM code. Sigh. There is
enough room to fit all of the OS code into free RAM above DUP and not over-write
it. But it's a consideration you must prepare for in advance.
If you aren't used to burning your own chips, I suggest
you start slowly. Try a 2K or 4K EPROM before tackling a larger project.
It's easier to erase and reburn, although burn time itself is only a few
minutes. Learning to burn your own chips isn't really difficult. But because
so little written help can be found anywhere, you must figure out a lot
of the finer points by trial and error.
The Proburner has several built-in safety routines, such
as a timer to wait while the cart sets up its internal hardware necessary
for burning. There's also an automatic erase check-and-verify when burning
an EPROM.
The instructions on inserting and reading a chip are well
enough explained to be easily understood by novices. But otherwise, the
Proburner manual leaves much to be desired. It's terse, to say the least.
And it's written for those who already understand EPROM burners, not the
novice. Proburner designer Peter Thompson tells me that rewriting the manual
for a less-experienced reader is currently his main priority. But for the
experienced user, Proburner is much easier to understand and operate than
all others I've seen for the home market.
Specify your computer model when you order a Proburner.
The XE version required the addition of a smaller capacitor to reduce signal
noise-it will run happily on the older models but the 800XL version is
not compatible with the l30XE.
Proburner opens the door for Atari users to get into the
mysteries and joys of chip burning without seriously damaging their pocketbooks
or causing severe frustration. I recommend it highly.
Proburner is available from Thompson Electronics, 1074
Kensington Avenue, Suite 188, Buffalo, New York, New York 14215. Telephone
(416) 960-1089. The cost is $149, 32K cartridge.