Bart said:
I recently acquired an EPROM programmer that plugs into my printer port on
my PC. The software allows me to take all the hex info off one chip and put
it on another, or edit the hex info (hex editor) as I guess most programmers
do.
Is there any "cool" stuff I can do with this thing? I fantasized taking the
EPROM off my 486 motherboard, copying it into a larger capacity chip and
adding DOS onto the chip but the Internet searches lead me to believe that's
apples and oranges.
Most of my searches tend to imply that programming an EPROM is proprietary
to a processor/microprocessor and not much mention of software to make
things happen between the two. Is there anything "neat" I can do with just
my EPROM programmer without getting deeply involved integrating a processor?
Can I put a small database on an EPROM chip with my programmer, then mount
the chip on a small circuitboard that plugs into a serial/parallel port on a
PC and access the data with a simple QBASIC program?
Hoping there is something else "cool" I can do with EPROM chips than just
copy them.
Any help is appreciated,
Bart
Hi, Bart. There are quite a few things you can do with EPROMs as a
hobbyist (most of them a little dated and clunky in comparison with
just using a PIC), but the "cool" part of your burner/programmer is at
the other end of the cable.
The printer port is a remarkably versatile collection of Input/Output
pins. By being connected to the PC, you can use those I/O pins to
sense and control any number of things.
If you want to look into this, the best place to start is Jan Axelson's
Lakeview Research website:
http://www.lvr.com/parport.htm
This website has a number of really good links which will give you a
start in programming and interfacing with the printer port. I'd also
highly recommend Jan Axelson's book, "Printer Port Complete", which
shows how to do it all in one place. It's well-written and very
suitable for people who don't have a degree in electronics, and also
provides an accompanying CD which gives numerous examples in several
programming languages.
A few pieces of advice. First, start out with your parallel port set
in SPP mode (you can do this by tweaking the PC BIOS). Programming is
simpler, and there's less chance of a newbie letting the smoke out of
the printer port or interface circuit if the I/O pins are dedicated
innies or outies.
If you're comfortable with M$DOS, it's a better OS for newbies because
you don't have to negotiate with Windows for control of the port I/O.
And if it doesn't make you gag, you might want to start out with DOS
and M$ QBASIC, the further crippled version of the already crippled
QuickBASIC. It's included free in M$DOS 5.0 and up. This will gives
you the fastest and cheapest start in reading printer port pins and
turning outputs on and off. Actually, if you know what you're doing,
you can plug in your interface circuit, boot your computer with M$DOS 5
and the printer port in SPP mode, load QBASIC and read the printer port
input pins and set output pins with only a couple of lines of code in
the Immediate window. Can't get easier than that.
Wiring errors and code errors errors can both result in damaging the
printer port, and you should be able to either throw out the PC or
replace an I/O card without cursing your bitter fate (voice of
experience). Remember that newer computers (last 10 years) and all
laptops have the SMT printer port chip on the motherboard, so smoking
this IC usually means throwing out the motherboard, or at least,
getting stuck and having to deal with a big repair hassle.
So if you're going to be experimenting with the printer port, I'd
recommend you use an old junker PC you can afford to throw away for the
hardware debugging part of projects. You can get junkers at garage
sales or by dumpster diving from businesses that are upgrading their
PCs. This is usually the best way, because you can get frequently get
identical machines in quantity, most of them are fairly new, and nobody
really enjoys throwing out something that still works. Some businesses
will be happy to let you scavenge the old boxes as long as they trust
you to wipe the hard drive first. A corollary to this is checking at
your local religious primary and high schools. They are the foremost
recipients of donated business PCs, and are always trying to rotate the
oldest ones out. Be sure to volunteer to move them out yourself.
Since you want to feel good about this, offer a few bucks each, too.
Saint Liebowitz will thank you, and it's always good to have him on
your side, offering up a prayer for your circuit when you turn the
power on. ;-)
Good luck
Chris