Whether or *not* you got the Heathkit EPROM Programmer, please tell us: Why do you need *this* particular programmer??? Would
*not* any EPROM programmer work just as well??? Do you have a lot of Heathkit gear???-- +----------------------------------------+ | Charles and Francis Richmond | | | | plano dot net at aquaporin4 dot com | +----------------------------------------+
Hi Charles,
I'm gonna give it my best shot when the auction closes tomorrow but it may go too high for me. What I like about this programmer is that, I believe, it can also function as an eprom simulator. I haven't found any other simulators that support the older 2716 and
2732 eproms... heck, it isn't easy finding any simulators these days. Of course I can continue the burn, burn, burn and batch erase routine but being able to quickly try something will have its benefits. This activity all centers around writing custom code for old 1980 vintage pinball machines that are motorola 6808 based and use primarily 2716 and 2732 eproms. One of my test fixtures (which uses custom code on the pinball boards) can be seen here:Now I'm attempting to take the diagnostics to a more detailed level.
As far as heathkit... I only have a line following robot that I built when I was a kid... but I remember the stores and I can see myself getting hooked on collecting heathkit... I'm sure my wife hopes that I don't!
take care, Tim
TXMarsh:
I should have three ROM emulators made by Parallax (the one of the Basic Stamps) a little less than 20 years ago. But they work on the paralel port and I don't have the related (clearly DOS) software. If you can find it I'll be happy to send them to you.
-- Saluti
Why not use EEPROMs? Erase times would be much less.
Wow. Something like that would have been great back when I was a twenty year old pinball repairman, even though we mostly had Bally machines.
-- Mike McGinn FACOCM You won't look forward to the trip! No electrons were harmed in sending this message. ** Registered Linux User 377849
I built a number of those. 4 x 2116 stacked on top with three pins bent out, a 74H138 to demux the next bits + enable, a 7404 and a switch to set rw/ro mode, and a little 6V alkaline battery assebly and a diode with 0.85V drop to feed it while not connected to power, all assembled into a DIP cradle.
Plug into base machine, set RW switch, write memory, set switch to ro, unplug, plug into test object, boot.
I never made drawings, just soldered it together for a commodore PET project. It got popular, so I had to make copies.
-- mrr
Morten Reistad:
In mine the RAM is a single chip in a 24 or 28 pin wide DIP. They have a flat cable with a DIP connector that plugs into a 27C51 socket, two modular plugs for the parallel port and for daisy-chaining other emulators, no battery, diodes or switches, as they are powered by the target and do not need to be unplugged from either the PC or the target.
Good! :-)
These days you could probably add a set of ports to a PC, wire them to a DIP plug and emulate the EPROM in software complete with the timing characteristics.
I can't think why you'd want to but ...
-- Steve O'Hara-Smith | Directable Mirror Arrays C:>WIN | A better way to focus the sun The computer obeys and wins. | licences available see You lose and Bill collects. | http://www.sohara.org/
Ahem A Rivet's Shot:
I definitely don't think so. A PC must handle lots of unpredictable interrupts that will skew the timings. On the other hand, using a parallel FTDI chip...
-- Saluti
Not in Windows, you won't. Maybe DOS, or Linux in single-user mode.
Good Luck! Rich
Without an OS at all was what I had in mind - DOS come close enough though.
-- Steve O'Hara-Smith | Directable Mirror Arrays C:>WIN | A better way to focus the sun The computer obeys and wins. | licences available see You lose and Bill collects. | http://www.sohara.org/
They can all be turned off.
Sure that'll work.
-- Steve O'Hara-Smith | Directable Mirror Arrays C:>WIN | A better way to focus the sun The computer obeys and wins. | licences available see You lose and Bill collects. | http://www.sohara.org/
This is definitely a project where the right way to do it would be to have a little PIC managing low-level timing, and talking to the PC over USB.
-- As we enjoy great advantages from the inventions of others, we should be glad of an opportunity to serve others by any invention of ours; and this we should do freely and generously. (Benjamin Franklin)
Well my bid of $125 fell short. The unit sold for $130. I guess 1986 technology is still in broad demand! Probably for the best... I think you are all correct that I should be able to build one of these... add one more project to the list! : ) Tim
Joe Pfeiffer:
Noplis.
-- Saluti
Sorry? (I'm afraid I only read English)
-- As we enjoy great advantages from the inventions of others, we should be glad of an opportunity to serve others by any invention of ours; and this we should do freely and generously. (Benjamin Franklin)
Joe Pfeiffer:
"No, please".
If you are used to PIC's demented assembly, you should have been able to decipher it easily.
-- Saluti
I suppose it would sound lame to say that occurred to me, but I figured it must have been a real word....
Their instruction set is certainly weird, but their processors are so perfectly suited to tasks like this...
-- As we enjoy great advantages from the inventions of others, we should be glad of an opportunity to serve others by any invention of ours; and this we should do freely and generously. (Benjamin Franklin)
Joe Pfeiffer:
Have you ever taken a look at Atmel's AVRs? Since I did, no more PICs.
-- Saluti
Rubbish, unless you are doing bare-metal programming on the PC (and no sane person would do that).
No, it will not work - USB 1.1 (as used by most FTDI chips) runs on a 1 ms cycle. Even with USB 2.0 (as used by some faster FTDI chips) runs on a 0.1 ms cycle. This means that any time you need to read a port then set some outputs based on the inputs, you have an absolute minimum of
0.2 ms latency - three orders of magnitude too high for an eprom emulator. For proper emulation of the signal sequencing, you would need several read-write cycles making it even worse.That's almost right - but drop the "PIC". They are horrible devices, and too slow here. Even using a decent small micro like an AVR, you couldn't emulate an eeprom at more than about 1-2 MHz. And if you have a chip that is fast enough, it is difficult to get consistent timings.
A much better idea is to use a small programmable logic device with a ram chip and a USB connection. You don't need much - a 128 macrocell PLD would be enough if you use an FTDI chip for the usb connection. Or you could buy one of FTDI's modules with a Cylone FPGA - it's overkill, but easily available and ready-made.
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