27C400/27C800 EPROM emulator

Any 8bit repairs, images, cool things, upgrades etc.
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cmorley
Posts: 291
Joined: Tue May 28, 2019 5:46 pm

Re: 27C400/27C800 EPROM emulator

Post by cmorley »

Tidy up continuing - just buttoning up a few things. It seems newlib-nano doesn't really live up to its name. I binned off the ctype library functions and saved 800 bytes of unnecessary c-locale information. On a 32K FLASH MCU that is huge.

95% of the strings are now refactored into the string table now so translation would be pretty easy... I might add the option because unless the FLASH erase & program library busts my .text section limit it is a 4 line function (flash unlock, flash erase, flash program, flash lock).
Squirrel61
Posts: 15
Joined: Wed Dec 18, 2019 5:22 pm

Re: 27C400/27C800 EPROM emulator

Post by Squirrel61 »

Thanks again for all the work you're putting in this! I can't wait until you start distributing them!
cmorley
Posts: 291
Joined: Tue May 28, 2019 5:46 pm

Re: 27C400/27C800 EPROM emulator

Post by cmorley »

Programming the language from the menu doesn't fit in the MCU's code FLASH. It is a couple hundred bytes over. :(

A translation built from source would still be possible but probably not worth the effort. I have just corrected all the compiler warnings so it build warning free now. I'll package up the new firmware and send it to the testers.

I also built up ten of the modules from the new batch of PCBs. I am just waiting on some 1uF 0402 caps from Mouser to finish these off (Mon/Tue)... they work without the caps and the noise on the rail is within spec for the chips but it is smoother with them. The regulator doesn't need them for stability.

I'm thinking £20 for the issue D "beta" units. The final release issue 1 might be more or might be cheaper - it depends on the economy of scale I can achieve and yield from the assembly house. For now issue D are all hand assembled by me :?
reinauer
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Joined: Sun Jan 12, 2020 6:56 pm
Location: United States

Re: 27C400/27C800 EPROM emulator

Post by reinauer »

Will they fit in an A4000D? If so I would like to order 2 of the latest batch if still available.
cmorley
Posts: 291
Joined: Tue May 28, 2019 5:46 pm

Re: 27C400/27C800 EPROM emulator

Post by cmorley »

reinauer wrote: Sun Jan 12, 2020 8:22 pm Will they fit in an A4000D? If so I would like to order 2 of the latest batch if still available.
I think the A4000 has the same ROM pinout as the A1200. Google says 27C400 for A4000 - if so then yes they should work. There will be plenty to go around I can easily order more parts and assemble a few more.
cmorley
Posts: 291
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Re: 27C400/27C800 EPROM emulator

Post by cmorley »

No capacitors today. Fedex website claims I wasn't in which is BS. No delivery attempt & no card. :x

edit: They did turn up at 2pm on a before 12 service. So log it on the system as undelivered at 10:39am then deliver it at 2pm... is that better or worse than a few years ago when they were logging as delivered before noon then throwing the parcel at me at 2pm? :|
cmorley
Posts: 291
Joined: Tue May 28, 2019 5:46 pm

Re: 27C400/27C800 EPROM emulator

Post by cmorley »

Booting diagrom on an A1200:
Photo0892.jpg
Photo0892.jpg (115.82 KiB) Viewed 4783 times
Switching between Diagrom 1.2 and KS3.1.4 working on the A1200. I don't have a spare A1200 keyboard so triggered the ROM switch from the USB.

I might make the boards a fraction narrower in issue 1 for side to side. These issue C fit like a glove because they were individually milled out - the issue D are V-groove so might need a quick swipe on sandpaper (or don't snap them apart!).

I will make a thread in the GENERAL->PC SALES (as they aren't Atari sales) to take names for beta units.
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rubber_jonnie
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Re: 27C400/27C800 EPROM emulator

Post by rubber_jonnie »

cmorley wrote: Mon Jan 13, 2020 12:20 pm No capacitors today. Fedex website claims I wasn't in which is BS. No delivery attempt & no card. :x

edit: They did turn up at 2pm on a before 12 service. So log it on the system as undelivered at 10:39am then deliver it at 2pm... is that better or worse than a few years ago when they were logging as delivered before noon then throwing the parcel at me at 2pm? :|
Don't get me started on couriers. On Monday they left £150s worth of air tank on my front doorstep for all the world to see. I was working from home all day, saw a DPD van arrive, and got no ring or card, so assumed it was for somebody else.

My wife found it when she got home from work at 16:00.

On another note, I am up for testing these if you're still in need.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
nikoskon
Posts: 19
Joined: Mon Sep 16, 2019 10:18 pm

Re: 27C400/27C800 EPROM emulator

Post by nikoskon »

Great little project there :o
Will definitely be in for a few of these when available, 2 for A1200 and 1 for the others (A500, A600, and A2000) :D
Squirrel61
Posts: 15
Joined: Wed Dec 18, 2019 5:22 pm

Re: 27C400/27C800 EPROM emulator

Post by Squirrel61 »

I'm in for 1 or 2 too. I guess the PC SALES topic hasn't been opened yet, because I couldn't find it. Maybe you can link it here as soon as you open it?
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