jhumphre@rucs2.sunlab.cs.runet.edu (Jeff Humphrey (Jeffus)) (04/05/91)
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* Attention Poor Hardware Hackers *
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The college kids' ROM emulator is here. I've been watching those
ads in Circuit Cellar for a couple of bi-months, the ones for the
129 dollar ROM emulator. I finally came up with the government
college fund money (tax refund) to buy something moderately large
so I decided to take the chance. I received it the other day and
have had plenty of time to run it through it's paces. I am VERY
impressed (as impressed as one can be over a ROM emulator).
The emulator itself is extremely simple, a 3"x5" circuit board,
a 28 pin jumper (for the ROM socket), phone cable, and a connector
for your computer's printer port. You connect the phone cable to
your computer with the socket they provide, plug the other end into
little circuit board (the emulator), then plug the 28 pin jumper
into the socket for your ROM in the project you are building. They
also provide a little wire that you connect to the RESET pin on
the target processor which will reset the system when the emulator
is finished downloading code. The emulator can handle 2764, 27128,
and 27256 ROMs.
The software provided with the emulator is pretty good. The
main program on the disk is called PRE.EXE which handles the
downloading of Intel, Motorola, Standard Hex, and BIN files to
the device. It also has a built in editor for you files so that
you can make changes or whatever directly to the hex data. Also
included with the software package is a bit of assembly code for
downloading data from your homemade programs directly to the
emulator without using PRE.EXE (why ... I have no idea).
The basic emulator comes without RAM installed but you can get
one with 32x8K static for 124 bucks, or 32Kx8 NV for 169 dollars.
I just plugged in an 8K static and I can emulate most anything I
have any buisness playing with.
Problems: I liked everything about the emulator except that you
have to keep power to your project's circuit for the device to
work. You cannot download a program to the emulator if the
power is off on the target system, the emulator is powered by
the target.
Why is he so excited you might ask .... it's simple, the whole
deal only put me out ONE HUNDRED AND TWENTY NINE DOLLARS, nearly
the price of a gallon of milk these days AND the people were
really nice on the phone. A little added bonus for in '90s.
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This is my signature. There are many like it but this one is mine.
... if you don't get it ... don't ask.
------------------------------------------------------------------------------bender@oobleck.Eng.Sun.COM (I want to be eating rich soup in another town) (04/05/91)
In article <1991Apr5.033756.276@rucs2.sunlab.cs.runet.edu> jhumphre@rucs2.sunlab.cs.runet.edu (Jeff Humphrey (Jeffus)) writes: > > The college kids' ROM emulator is here. I've been watching those > ads in Circuit Cellar for a couple of bi-months, the ones for the > 129 dollar ROM emulator. Ah, yes, the days of ROM emulators, I remember them well! In the early 80's my friend Ralph and I were in college (for EE degrees) by some magic grace, and on the side we built various devices, mostly for our electronic music hobby and for lighting control for our band and so on; stuff that was commercially available but cost $$, so we built it instead. Well, we got to the point where we were blowing EPROMS with every code change, and in the back of our minds we didn't think that EPROMS liked being programmed/erased 20 times an hour, and besides, it took a long time to blow a 2764 (we had an inexpensive EPROM programmer that didn't have any of the new intelligent programming algorithms, so the bigger the EPROM, the linearly longer the programming time). We couldn't solve the programming time problem, but we were also up against the fact that we had a finite supply of EPROMS, and eventually we got to the point where all of our EPROMS were either in the eraser (20-40 minutes) or being used in a circuit somewhere, so I built a ROM emulator. It was a small box with some 6116 SRAMS in it, a ribbon cable with a DIP plug (from Radio Schlock), a toggle switch (for write protect/program mode) and an 1/8" jack for power to keep the SRAMS powered up as we moved it from the EPROM programmer to the target system (in those days, we didn't call it a target system, we just called it the "thing" that we were working on :-). It worked pretty well, and we used it quite a bit until we could borrow 8048 and 8051 ICE's from school, which was like being in a totally new universe. I think we still used the ROM emulator for some things, but since most of our designes were single-chip 8048 and 8051 designs, we used the ICE's for most of the development. Now of course at Sun we have these ROMBOS (I kid you not on the name!) super-fancy ROM emulators with a serial port that can emulate every EPROM/ROM/PROM known to mankind, plus a few of your relatives to boot! But those days spent in the basement of our rented house until the sun came up were some of the best in my life. Have fun emulating! mike -- Won't look like rain, Won't look like snow, | DOD #000007 Won't look like fog, That's all we know! | AMA #511250 We just can't tell you anymore, We've never made oobleck before! | MSC #298726