X8/X16/Xwhatever "Pure" FPGA Unique Sales Proposition

Scott Robison · Post by **Scott Robison** » Fri Oct 15, 2021 5:00 pm

A question original posed elsewhere by@Janne Sirén, relocated here to avoid the appearance of me derailing another thread:

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I hope this is a suitable thread to answer in, coming from the X8 poll thread. Moving onwards from any of that debate, I guess my question/point is how/what do you perceive the unique sales proposition being for an FPGA-only X8 or X16? There are certainly FPGA-only computers already out, but usually they have some other USP such as a case/compability/legacy with ZX Spectrum Next or the MEGA65, or they are lean-mean FPGA monsters like the MiSTer family, the ZX-One family or training boards such as Nexys. Others, like the Foenix computers, have the unique proposition of offering several discrete chips such as "real" processors and several hardware sound chips in addition to FPGAs.

What would be the unique sales proposition of a simple FPGA board like X8/16 that could easily run on any existing FPGA platform that are already being produced? I am genuinely curious about your answer and I hope my question also illustrates the area where I think it would be beneficial for the X16 project to continue having a clear message and a clear point.

While the initial question was posed to @Scott Robison I certainly think everyone is welcome to pose their own thoughts.

Mtemal · Post by **Mtemal** » Fri Oct 15, 2021 5:03 pm

Im not @Scott Robison but I think one perhaps unintended side effect of the X8 is the possibility that it can be programmed to run other 8bit/6502 Machines in FPGA alongside the VERA in FPGA for Video output. Granted that would probably require "erasing" the X8 ROM and assuming the ICE40UP5k could be programmed multiple times means that the X8 platform could be the basis for a truly inexpensive 8bit AIO FPGA machine.

Janne Sirén · Post by **Janne Sirén** » Fri Oct 15, 2021 5:08 pm

Thank you, Scott. Indeed I am very interested in your thoughts. When X16 used to be a 65816 processor and a pair of discrete video and audio chips, that was something unique. Today the Foenix project of course offers almost that in a range of several professionally manufactured computers (the video is FPGA, but otherwise).

If the X16 is turning into more of a simple FPGA board, what is unique about it that isn't already out there? For example, here is the SiDi FPGA from the ZX Spectrum community:

https://manuferhi.com/p/sidi

89 € ($100), professionally produced and finished/cased, available today. Or 69 € ($80) professionally produced without the case. This is one of maybe 20 variants of simple FPGA computers made for running Spectrum, Commodore and similar cores that are readily available at lucrative prices. These are fairly powerful little machines with a plethora of connectors as well.

Janne Sirén · Post by **Janne Sirén** » Fri Oct 15, 2021 5:13 pm

On 10/15/2021 at 8:03 PM, Mtemal said:

Im not @Scott Robison but I think one perhaps unintended side effect of the X8 is the possibility that it can be programmed to run other 8bit/6502 Machines in FPGA alongside the VERA in FPGA for Video output. Granted that would probably require "erasing" the X8 ROM and assuming the ICE40UP5k could be programmed multiple times means that the X8 platform could be the basis for a truly inexpensive 8bit AIO FPGA machine.

If it is that, there is already an entire range of MiSTer and ZX-Uno based FPGA boards that probably do such things even better and cheaper.

Mtemal · Post by **Mtemal** » Fri Oct 15, 2021 5:16 pm

Wow, that SIDI is one heck of a machine.

Janne Sirén · Post by **Janne Sirén** » Fri Oct 15, 2021 5:17 pm

On 10/15/2021 at 8:16 PM, Mtemal said:

Wow, that SIDI is one heck of a machine.

And I mean, there are 10-20 more like it. They have been making really great FPGA computers in the ZX Spectrum/C64 and ST/Amiga communities for the past decade+. They've nailed it down to an art by now, very cheap, very powerful too.

Scott Robison · Post by **Scott Robison** » Fri Oct 15, 2021 5:21 pm

From a purely legal standpoint, in a pure FPGA solution, the ROM is what makes the X-whatever unique. It is based on intellectual property from Cloanto (the kernal, as the current successor to Commodore) and Microsoft (BASIC, though I don't know how the initial license fee Commodore paid transfers to Cloanto but it seems it does indeed transfer). As such, these are not free to copy to other platforms. So having a retro-inspired computer with legally licensed ROM that is derived from the Commodore heritage is one USP. While it would be possible to port the HDL that makes the hardware to other platforms, it would be "useless" to most people without the ROM, and that is encumbered in its current state.

Having a compact FPGA based design that is not subject to some of the downsides of software emulation is another USP. Software emulation is great, and I quite enjoy my The C64, but it isn't ideal. Especially if you think of a Raspberry Pi form factor, an FPGA solution that behaves as a real hardware solution is going to be superior to porting the emulator to an existing SBC platform.

While not directly related to the FPGA nature of the original question, a PETSCII inspired keyboard with symbols printed on the keys is a third USP for the project as we understand it at this time.

Given some time and less of a time crunch (I have to get ready to go teach some middle schoolers how to write Python) I may be able to come up with more, but I think those three are significant. Whether they are enough to entice people to buy into the platform is another question.

Scott Robison · Post by **Scott Robison** » Fri Oct 15, 2021 5:23 pm

On 10/15/2021 at 11:13 AM, Janne Sirén said:

If it is that, there is already an entire range of MiSTer and ZX-Uno based FPGA boards that probably do such things even better and cheaper.

I'm not familiar with the ZX-Uno (I mean, I've heard of it but literally know nothing else). The MiSTer is nice, though it currently costs a lot more than we expect an FPGA X16 to cost (though we're guessing on that based on past information that is incomplete).

Janne Sirén · Post by **Janne Sirén** » Fri Oct 15, 2021 5:29 pm

On 10/15/2021 at 8:23 PM, Scott Robison said:

I'm not familiar with the ZX-Uno (I mean, I've heard of it but literally know nothing else). The MiSTer is nice, though it currently costs a lot more than we expect an FPGA X16 to cost (though we're guessing on that based on past information that is incomplete).

ZX-Uno is basically a whole family of FPGA computers that run various cores. One variant available here for 55 € ($65):

https://www.antoniovillena.es/store/product/zxunoplus/

As for MiSTer, SiDi is MIST compatible (all but its largest cores) and costs 65 € ($80):

https://manuferhi.com/p/sidi-fpga-sin-carcasa-without-case

I believe both ZX-Uno and SiDi are way more powerful than X16/X8.

Scott Robison · Post by **Scott Robison** » Fri Oct 15, 2021 5:29 pm

Oh, a fourth USP: Building on from the Commodore heritage. By this I mean more than just the ROM, I mean the system as a whole. 17M+ C64 computers, 1M+ VIC 20, 5M+ C128. I know there are a lot more of other computers out there at this point, but the Commodore and 6502 lineage is going to appeal to a completely different audience than the Sinclair and Z-80 lineage. That doesn't make one better and the other worse, but I think this is the first time someone has tried to put out something like this (FPGA based actual hardware vs emulation on an ARM or other alien hardware platform) at something like this price point. The fact that the Sinclair inspired models have done as well as they have I think indicates the market might really enjoy something like this. Similar space, similar objectives, achieved differently.