exxos's Atari, Amiga & retro forum

Hey guys,

I'm the author of zeST, an open-source Atari ST clone for cheap FPGA prototyping boards.
It was designed with cycle accuracy in mind (it uses Ijor's fx68k 68000 core), and uses modern peripherals: HDMI, USB, bluetooth etc.
Its turbo mode allows it to run at 50 MHz.
It supports up to 14 MB of ST RAM, has floppy/hdd emulation, as well as a GEMDOS drive.

With the introduction of the blitter in yesterday's release we can say it can do anything a ST, STF or Mega ST can do!

I think I haven't told much about it on this forum before, so that's the occasion.

Have a look at the website: https://zest.sector1.fr/

I hope some of you will find it of interest, and I'd be glad to discuss about it.

Cheers

Congratulations!

I've not dipped my toe into these waters yet, but that sounds like a great milestone & I like the fact it's open source too.

Best of luck!

David.

What kind of prices are the Zynq 7010 devboards? These were the cheapest I could find.

Z7-Lite ~ £75
DL0001 ~£79
Zynq Zero ~£73

alexh wrote: 19 May 2026 13:45 What kind of prices are the Zynq 7010 devboards? These were the cheapest I could find.

Among these, only z7-lite is supported.
DL0001 could be supported if there's demand for it.
Zynq Zero is not suitable because it has no USB host port (for keyboard/mouse etc)

May I just suggest to consider 7020 models; some are not much more expensive and may be more suited to future zeST releases.

What I would *love* to see is further STE support. We have so many great options for the ST (including Exxos' very own H5 clones) but nearly nothing (?) for the STE.

@zerkman
great,

maybe a stupid question, will it work with Tang Nano 20k?

Cyprian wrote: 20 May 2026 14:26 maybe a stupid question, will it work with Tang Nano 20k?

Similar RTL to what is inside ZEST is already available on the Tang Nano 20k

https://github.com/MiSTle-Dev/MiSTeryNano

However Zest offers lots of features Tang Nano 20k won't be able to do because of it's Hybrid FPGA.

mikro wrote: 20 May 2026 00:25 What I would *love* to see is further STE support. We have so many great options for the ST (including Exxos' very own H5 clones) but nearly nothing (?) for the STE.

I imagine this FPGA platform can do STe? There are open-source RTL hardware designs for STe chips including the GSTMCU (Glue + MMU) coded directly from the Atari chip schematics and STe shifter reverse engineered by Jorge Cwik who also did the FX68k. It would require slightly higher FPGA capacity compared to ST but not much.

I just noticed that the OP implemented their own HDL for most of the ST chipset including the YM2149. Kudos, very cool. I had assumed you had used the Jotego JT49 core and the other open source cores available.

Cyprian wrote: 20 May 2026 14:26maybe a stupid question, will it work with Tang Nano 20k?

No, it won't work. It's a different project from Misterynano.

alexh wrote: 20 May 2026 14:41I imagine this FPGA platform can do STe? There are open-source RTL hardware designs for STe chips including the GSTMCU (Glue + MMU) coded directly from the Atari chip schematics and STe shifter reverse engineered by Jorge Cwik who also did the FX68k. It would require slightly higher FPGA capacity compared to ST but not much.

Yes STE would probably work on this platform. I did ST because it was simpler to do, and also because it's the machine I had when I was a teenager. zeST might even support STE in the future though, who knows?

alexh wrote: 20 May 2026 14:41I just noticed that the OP implemented their own HDL for most of the ST chipset including the YM2149. Kudos, very cool. I had assumed you had used the Jotego JT49 core and the other open source cores available.

I was not even aware of that JT49 core :) But I did this project mostly for fun, so it would not be much fun to reuse existing components.
The only exsting open source components I used are the processors (68k and hd6301), because I was beginning in hardware design when I started zeST and I would not be able to build a working processor at the time. Also the ACIAs, because it's a boring component anyway.