EPROM Programmer

[msknight]

OK - so, I've got a ZX81 ... ok, ok, I've got six... and I would like to change the BIOS.

Now... I'd like to replace with something that's going to last about 40-50 years. I do have EEPROMs but they're slated to last 10 years. I have read up on the way that they test EEPROMs to see how long they're going to last and I accept that a program on there could last maybe 20 years tops. I have also looked up the EEPROMs that last 100 years, but the minimum order quantity had me choking on my tea. - Also, to put one of the EEPROMs into the ZX81 require pin bending, so un-bending the pins to re-do it in a decade or so's time is likely to wreck the chip.

So, I'm looking to make a jump into 32K EPROM programming ... under Linux.

Yes, I am aware I could use a BBC B to do this, but I don't have an eprom programmer for that either and from what I've seen on fleabay, I think I'd rather a brand new EPROM programmer that I can hook up to Linux and use that way. There's so much that only comes with Windows software, or else requires software to be compiled, that I'm not sure where to turn in order to not waste money.

Grateful for thoughts and advice please.

[roland]

I use an XGecu TL866II Plus programmer in Linux. The software runs fine with wine. Even firmware updates run without problems. It's also possible to run the software in a virtualized Windows (XP) system in VirtualBox.

[msknight]

I'm trying to avoid wine, it's a lot of libraries, we've got the threat of 32 bit library removal from Linux and all that stuff that they keep threatening... and keeping gigs of VM drive just to run the software is a little overkill. To my mind there should be an easier solution out there.

[baz4096]

Is this any use? Not tired it myself:

https://gitlab.com/DavidGriffith/minipro/

[msknight]

Thanks. I'll give it a look. It seems that I might have to make/compile it, and I usually never have much luck doing that.

[chrissawer]

I use a TL866II Plus on Linux with minipro, it works well and wasn't too hard to compile IIRC - I am on Linux Mint. Happy to help out if you have any questions.

A couple of things to be aware of. Firstly the TL866-II hardware (grey with teal ZIF socket) seems to be EOL, replaced by the T48 (also known as TL866-3G) which is black. You can see from this topic that gordonDrogon was recently looking for the older model specifically because it works on Linux: https://www.stardot.org.uk/forums/viewt ... p?p=407735

The other thing to be aware of is that most USB powered programmers will not manage programming voltages of 21 or 25V as required for older EPROMs. I have used mine mostly for "modern" 27C128/27C256 devices which work fine.

[sweh]

I use minipro as well. I left myself a note on how to use it

Code: Select all

  cd /home/sweh/src/minipro
  ./minipro -p AM27128A@DIP28 ...
    ... --read         -r <filename>   Read memory
    ... --write        -w <filename>   Write memory
    ... --verify       -m <filename>   Verify memory
    ... --blank_check  -b              Blank check.

IIRC compiling wasn't too bad; it requires libusb-1.0 development libraries (which maybe libusb-1.0-0-dev on Debian; I don't recall).

[msknight]

I've managed to get a TL866II Plus for a little under £70 with adaptors.

Grateful for any advice as to 28 pin eproms to use with it, with the target being a ZX81 BIOS please? (8K image loaded into a 32k EPROM four times should enable it to read a ROM image if I have to tie the extra address lines high)

[msknight]

I'm looking at these - https://cpc.farnell.com/atmel/at27c256r ... dp/SC09509 - many others seem to be listed as no longer manufacturered. Would these work?

If i'm reading the datasheet correctly, they only require a little over 6v to program them. They do seem to be one-time programmable only, so can't be erased and re-written.

[msknight]

Or these, which seem to have good supply and in demand? https://uk.farnell.com/microchip/at27c2 ... dp/1095781

[baz4096]

Or these, which seem to have good supply and in demand? https://uk.farnell.com/microchip/at27c2 ... dp/1095781

These are one time programmable only. As to their suitability for ZX use, I can't say I'm afraid, sorry!

[BeebMaster]

I think both of these are the same part, the datasheet links to the same document. I used to use these in the Disc & Econet kits. The programming voltage is 12V (datasheet seems to suggest 13V +/- 0.25V) and they always programmed fine (apart from the odd failure over the years due to bad connection I think) in my Morley V2 programmer at 12V.

[msknight]

If anyone has any other suggestions on this, before I pull the trigger on some of these, I'd be grateful.

I've got a pin out of the ROM and the couple of pin conversions required, here - https://msknight.com/bbc/zx81-rom.html

[IanJeffray]

If anyone has any other suggestions on this, before I pull the trigger on some of these, I'd be grateful.

TL866II has served me well, but I bumped up to the T56 for ease of programming 42pin DIPs without a lot of manual switch-flicking.

[msknight]

Thanks. Unfortunately I now have a TL866II on the way, which I'm fairly sure is probably going to be a clone and not an original.

I did that, however, because minipro, which I'll be using on Linux, says that T56 support is still experimental.

On that basis, and that I'm going to be sticking with relatively straightforward chips, I deemed that minipro was the thing to focus on and that the clone hardware should at least deliver what I need today... hoping that minipro will get better with T56 support as time goes on.