EPROM emulators

[SiriusHardware]

To avoid diverting other threads, I thought maybe we could continue on the subject of EPROM emulators here.

As Phil mentioned elsewhere they are a little bit past their sell by date now even for work on retro systems due to the arrival of FLASH programmable equivalents for many EPROMs but at the time they were a Godsend when the only alternative was to embark on a continuous cycle of programming, testing, erasing and reprogramming EPROMs. If you were lucky you had two or three of the correct type, one in use and two in the eraser so you could interchange them fairly quickly. Of course the alternative was to plan and write your code properly first time, but who could ever be bothered to do that?

I have a couple of devices at least which are capable of EPROM emulation, one is an ICE Tech Micromaster 1000E which is primarily a device programmer with the added capability of emulation, one is very much one produced by a one-man operation and goes by the name of 'JPD' and it is an emulator only. It is still useful today because communication / control is entirely via commands issued via a serial terminal, and you can also send Intel Hex to it via the same means. I used it extensively when I was rewriting control head firmware for a couple of PMR radios models which were popular about 25 years ago.

The SOFTY 2 (which I don't have) also included this capability and I think it was Timbucus who told me that one of these was in some way involved in the writing of the classic Sinclair Spectrum game 3D Ant Attack.

I'm not familiar with any of the current EPROM emulator designs, though.

[DrStrangelove]

I have a Crash Barrier EM3 emulator that hasn't been turned on in 20 years but did sterling work on an assortment of devices back in the dim & distant past.

I also have a Dataman S4 which emulates as well as programs stuff. I think the last thing it programmed was a 1Mb eprom which had a WAV file stuffed in for a project.

Crash Barrier are long gone, another one man band.

The EM3 uses an obsolete programmable logic chip which is handy.

[ChrisOddy]

Originally Posted by SiriusHardware

The SOFTY 2 (which I don't have) also included this capability and I think it was Timbucus who told me that one of these was in some way involved in the writing of the classic Sinclair Spectrum game 3D Ant Attack.

Ah, so I need to get on with the SOFTY 2 replica then !

[Jez1234]

Sorry to "thread crash" but would an Acorn Atom "Toolkit ROM" be any use to vintage computer types? My guess is it will be common and anyone who wants one has one... but if not then I have one I've been hanging on to for 40 years! It was burnt on an EPROM burner hence the title jogged my memory.

[SiriusHardware]

I have a feeling Tim(bucus) will be in touch with you shortly. He was just saying in another thread that he has just picked up an Acorn Atom.

Ah, so I need to get on with the SOFTY 2 replica then !

Indeed, although it may not be able to emulate anything bigger than a 2716?

[Phil__G]

Softy-E ?

[ortek_service]

Originally Posted by Jez1234

Sorry to "thread crash" but would an Acorn Atom "Toolkit ROM" be any use to vintage computer types? My guess is it will be common and anyone who wants one has one... but if not then I have one I've been hanging on to for 40 years! It was burnt on an EPROM burner hence the title jogged my memory.

I think I've got at least one copy of this, amongst a few Atom (EP)ROM's I picked-up. But if you've got access to a means of reading it out, you could upload it here somewhere / check whether it's already in the archives on Stardot etc.

[ortek_service]

From https://www.vintage-radio.net/forum/...d.php?t=203099

QUOTE=ortek_service;1579456]
>>
>>
and Kris Sekula's: FB EPROM EMU NG Users Group
- Which he was trying as a bit of an experiment to see if people preferred this over his original group, at https://groups.io/g/eprom-emu-ng
(But probably also a few on the groups.io group, who didn't really do FB)

>> and mainly using his EPROM-Emulator project on Commodore's etc.

>> and was always keen for anyone to tell him about / send pictures of his EPROM-Emulator being successfully being used on any system (Inc. Homebrew ones), that no-one else seemed to have tried so far.
- So it will be interesting to see when someone has it connected to an MK14 (Will require making a custom adaptor from its DIL header to the PROM sockets, although would plug into ChrisOddy's MK14E a bit easier) or other SC/MP system (Might be able to use the MM5204 to 2716 readout adaptor I made, for the NS Introkit).

And I have been meaning to make one of Kris's EPROM-Emulators, as he's put quite a bit of effort into making it as quick & convenient as possible to update the target's running-image from the link to a PC / compilers run on that. Whereas the EPROM-Emulator only one I think I've currently got is that built into the Dataman S3, as never quite got round to building an EPROM-Emulator myself that I'd originally designed to go with my EPROM-Programmer project I'd been working on in the 80's.[/QUOTE]

Originally Posted by Phil__G

I remember a few eprom emulator projects in the magazines back in the day, from eti, elektor, byte etc plus there were a few 'small ads' ones built by blokes in sheds
I never built or used one back then, and these days eeprom is quick & easy, and we all have a lot more coding experience than we had back then so hopefully fewer mistakes

Yes, I looked at these ETI etc. designs, when I started to design one back then. And mine was very similar, with a 32K RAM IC and tri-state buffers on the Address & Data lines both the target and host computer sides.
The other main way of making one, is to use a Dual-port RAM with these buffers and the necessary arbitration-logic built in.

A dual-port one does have some advantages, like that it may be possible to leave the target system running whilst modifying the 'ROM' - Although that could be inadvisable, and may be best to reboot each time.
It could also be possible to use Dual-port RAM as actual RAM in the target system, and interrogate it by the host, whilst target is running - So more of an Ice Circuit Emulator / Debugger.

Some typical (but rather more expensive/ may be discontinued) Dual port RAM's are:

IDT 7006 16Kx8
IDT 7007S55JI 32Kx8 $37
IDT 7008L25J 64Kx8

And ChrisOddy has used one of these, along with an Arduino Nano, in his own (Acorn System Eurocard) design , that allowed you to link a PC to an area of RAM in the Acorn-System.
So also kind of an In-Circuit debugger, rather than just an EPROM Emulator.

[ortek_service]

Originally Posted by SiriusHardware

>>
>>
The SOFTY 2 (which I don't have) also included this capability and I think it was Timbucus who told me that one of these was in some way involved in the writing of the classic Sinclair Spectrum game 3D Ant Attack.

Originally Posted by SiriusHardware

I have a feeling Tim(bucus) will be in touch with you shortly. He was just saying in another thread that he has just picked up an Acorn Atom.

Indeed, although it may not be able to emulate anything bigger than a 2716?

Well you could always use an original version (/replica of it) SOFTY in the meantime, as I believe these also functioned as an EPROM-Emulator (but with half the capacity of the SOFTY-2) / could directly replace an SC/MP CPU nvia its expansion bus.

Although it seems it would be hard work to use either of these with a Spectrum, and the later S3 / S4 would be much easier (But weren't released iuntil many years after the Spectrum, so weren't an option back then) - With the S4 still quite popular and sought-after as about the last Commercial one around but now also discontinued with no replacement.

[ortek_service]

Originally Posted by SiriusHardware

>>
As Phil mentioned elsewhere they are a little bit past their sell by date now even for work on retro systems due to the arrival of FLASH programmable equivalents for many EPROMs but at the time they were a Godsend when the only alternative was to embark on a continuous cycle of programming, testing, erasing and reprogramming EPROMs. If you were lucky you had two or three of the correct type, one in use and two in the eraser so you could interchange them fairly quickly. Of course the alternative was to plan and write your code properly first time, but who could ever be bothered to do that?
>>
>>

Well they are still sometimes better than using FLASH / EEPROM's, as you can just leave the Emulator semi-permanently connected and have updates done in seconds, rather than the continual IC-swapping from the days of having to program in an IC-programmer.

Originally Posted by SiriusHardware

I'm not familiar with any of the current EPROM emulator designs, though.

There doesn't seem to be many ones around at all anymore.
So probably what led to Kris Sekula designing his open-source published one / the odd other one being published.

About the only semi-commercial one we found was the Momik electronics memSIM-2 USB EPROM simulator.
This contains the following:

M5M5408BFP 5V 4Mbit (512K x 8) TSOP-52 RAM
3x 74VHCT541A 4.5-5.5V supply Octal Buffer/Driver TTL I/P Compatible
74LVC4245AD 3.3V Octal Transceiver
ATMega64A uC
2x 74ACT08 Quad AND-gates
74ACT32 Quad OR-gate
74ACT04 Hex Inverter
4x SIL9 = 32off Resistors Pull Up/Down to 34way DIP header

FTDI FT232? along with 2x 6N137 Optocoupler (For an isolated USB I/F?)
? DC-DC Converter module + ? DC-DC converter (3.3V from +5Vbus?)

Chris did buy one of these online, but gave up on it after a while, managing to resell it for almost what he paid for it, as despite trying various buffering / pull-up/down mods he found it was too flaky in his Acorn System.

[SiriusHardware]

Well they are still sometimes better than using FLASH / EEPROM's, as you can just leave the Emulator semi-permanently connected and have updates done in seconds, rather than the continual IC-swapping from the days of having to program in an IC-programmer.

It is arguably better for the hardware / the socket just to leave an emulator plugged in instead of constantly unplugging, removing, reprogramming and replacing a memory device, and if the emulator is a parallel connected device updates to the contents of the emulated memory only take a very short time, I agree.

[Jez1234]

Originally Posted by ortek_service

I think I've got at least one copy of this, amongst a few Atom (EP)ROM's I picked-up. But if you've got access to a means of reading it out, you could upload it here somewhere / check whether it's already in the archives on Stardot etc.

I do not have access to such equipment. Tim(bucus) has now PM'ed me so if he replies that yes he wants it then it is his. Presuming it works he should then be able to help you I guess.

[ortek_service]

Originally Posted by Jez1234

I do not have access to such equipment. Tim(bucus) has now PM'ed me so if he replies that yes he wants it then it is his. Presuming it works he should then be able to help you I guess.

That's OK, I've most-likely got a copy already as I have a collection of various Atom (EP)ROM's / Expansion board to let you select between various ones (as only one socket / memory area for these). - But it seems I haven't done a readout-backup on the PC yet, that I've been doing with most of my Acorn etc. ROM''s.
However, I have discovered this 'Acorn Atom Utility ROMs' Stardot page:
https://stardot.org.uk/forums/viewtopic.php?t=7372
Where people have mentioned 'Programmers Toolkit' / attached a copy:
https://stardot.org.uk/forums/download/file.php?id=8545
and apparently later renamed 'Program Power Programmers Toolbox' - also available, complete with documentation on there.

Plus some links from this, where there's a single file download of all Atom ROM's they have listed, inc. RM-RR-V12.000: RR-Toolkit, utillity toolbox with extra commands

[ortek_service]

Originally Posted by SiriusHardware

It is arguably better for the hardware / the socket just to leave an emulator plugged in instead of constantly unplugging, removing, reprogramming and replacing a memory device, and if the emulator is a parallel connected device updates to the contents of the emulated memory only take a very short time, I agree.

Yes, it does avoid doing all that / maybe fitting a ZIF-socket in development system if you're regularly having to do that - I once bought a (apparently Jaguar) ECU v.cheap that did have a ZIF socket fitted for its EPROM!
I would have though they'd tried and avoid any IC sockets, for max. reliability on a safety-critical system but have also seen them swapping socketed Memory IC's, for re-programmed ones on some Car repair / upgrade TV programmes.

With firmware, rather than PC application software, you might well need to write small test routines to workout how best to implement something with the hardware. So ability to make quite frequent changes quickly, may be quite important, and not just a case of being able to write all the code right first-time - Plus, it's not so easy to have software test-harnesses etc. on embedded firmware controlling hardware (especially if written in 'bare-metal' assembler, directly controlling the hardware.

Although, when things get tricky, you may also want to have single-step, breakpoints, & trace etc. functions that in-circuit processor emulators would give you (and now often get free built into many more-modern microcontrollers, via JTAG or other Debug/Programming interface - Although these may also have enough NV-Memory built in, to not require external ones).

[waltje67]

I (we in my group) use the memSIM2.

[SiriusHardware]

Hi Walt - do you have links to more information about that, is it a commercial product or open source, etc?

[ortek_service]

Originally Posted by SiriusHardware

Hi Walt - do you have links to more information about that, is it a commercial product or open source, etc?

Hi G, I actually mentioned this MemSIM-2 in my earlier post (#10) in this thread.

It is a (Low volume?) commercial product, as does come in a proper labelled plastic enclosure, and they do have a website (but all in Poiish?): http://www.momik.pl/

I found this via a quick Google for 'memSIM2', where first / only? hit is for an English guide to it: http://www.momik.pl/pdf/memSIM2_manual.pdf
- Where I had to go back to root URL to find their Home page.

It seems it is a closed H/W design at least, as I'd started to work-out the circuitry from the IC's that are used (a bit more complicated by its opto-isolation and level converters). But it looks like there maybe some open-source (3rd-party?) software for it: https://github.com/nils-eilers/memSIM2

There are also some discussions elsewhere about these:
https://www.retrobrewcomputers.org/f...31&goto=10093&

https://www.eevblog.com/forum/projec...lator-project/


However, I did mention that Chris bought one new (from an online Auction / marketplace?, where he re-sold it). But even after eventually getting it working with issues with quite-strong internal pull-up/downs? still found it was a bit flaky on his Acorn System. Although it seems others have been more successful on more-standard systems.

So I would probably recommended going for the completely open-source Kris Sekula design, that was previously nentioned, and he very-actively provides support for on various channels.

[SiriusHardware]

I remembered you mentioning these (MemSIM-2) units earlier in the thread, I was just interested to know what Walt, whose group seems to use them without any issues, felt about the units and whether he has had any difficulties along the lines of those encountered by Chris O.

[waltje67]

Originally Posted by ortek_service

Hi G, I actually mentioned this MemSIM-2 in my earlier post (#10) in this thread.

So I would probably recommended going for the completely open-source Kris Sekula design, that was previously nentioned, and he very-actively provides support for on various channels.

Yep, that is the one. I got it off eBay (new, by the manuf's) and it works jut fine. I do use my own software (which is based on another project, I just simplified it and took out a load of C++ code that was not necessary- or even useful) with it.

I have NOT used it "in" another system (such as an Acorn), just with and in my own SBC designs, and there, at least, it seems fine.

Fred (not Walt)

[SiriusHardware]

Oh, sorry, Fred, I was reading too much into your 'handle' obviously. Thanks for the info.