Flea Ohm Zero - FPGA AMIGA (Minimig) in a RPi-Zero-Formfactor

[guidol]

Did anyone see the Flea Ohm Zero at
https://hackaday.io/project/13048-flea-ohm-fpga-project

On YouTube is a video from the last year with a small (like now) FPGA running the Minimig Core:
https://youtu.be/mPIfhLXsYkQ

Now the new Board has a bigger FPGA (ECP5 FPGA from Lattice Semiconductor)

[nightshadowpt]

This looks interesting, although I am not sure how much size matters for these boards.

The current size of products like MiST is already quite compact to emulate an Amiga, can easily fit (almost) anywhere and it has more ports.

Nonetheless, it is still an interesting option.

Thanks for sharing.

[Dal]

This looks interesting, although I am not sure how much size matters for these boards.

The current size of products like MiST is already quite compact to emulate an Amiga, can easily fit (almost) anywhere and it has more ports.

Nonetheless, it is still an interesting option.

Thanks for sharing.

Portable handheld device perhaps?

[nightshadowpt]

Portable handheld device perhaps?

Touché!...

[Basman74]

Hello Everyone,

I'm the creator of the FleaFPGA 'Ohm' board mentioned in this thread. Thought it may interest you to know that I have now launched my homebrew board as an Indiegogo campaign

Although not strictly a gaming-oriented board, it does have some good possibilities for gaming (in our own opinion, at least ). If anyone has questions about it, feel free to ask. Thanks!

Regards,
Valentin Angelovski

[NegSol]

I like your board and the form factor - smaller is better

Having had trouble with shipping Indigogo backed hardware from overseas to Europe before might I ask you what your experience was with the 90 boards you already shipped in 2015? Any luck getting them through customs in Europe? Maybe even Germany?

[Basman74]

I like your board and the form factor - smaller is better

Thanks!

Having had trouble with shipping Indigogo backed hardware from overseas to Europe before might I ask you what your experience was with the 90 boards you already shipped in 2015? Any luck getting them through customs in Europe? Maybe even Germany?

Regarding my earlier boards: Apart from receiving the occasional complaint about paying customs duties, I had no problems shipping to europe. I did have some minor problems shipping to the USA or Canada.

Hope this helps. Valentin

[Basman74]

Duplicate post

[Higgy]

Great project Valentin, I am looking to back this.

I have a MiST and ZX-Uno (Spanish FPGA device). A highly portable AMIGA and old skool PC Core have got my interest! ZX Uno only has 512kb as standard so that limits its PC Core (based on Next186).

Question - is it possible to also get analog sound out? Or maybe within the PC and AMIGA Core it could be sent also to some GPIO pins?

[Basman74]

Great project Valentin, I am looking to back this.

I have a MiST and ZX-Uno (Spanish FPGA device). A highly portable AMIGA and old skool PC Core have got my interest! ZX Uno only has 512kb as standard so that limits its PC Core (based on Next186).

Question - is it possible to also get analog sound out? Or maybe within the PC and AMIGA Core it could be sent also to some GPIO pins?

Thanks Higgy for your encouraging words and also your question!

Yes - Next186 and Minimig both definitely have the possibility for audio out via the GPIO header (via hardware PWM of some pins etc.) as well.

Regards,
Valentin

[Higgy]

Options are always good as I am sure you agree (within price / tech constraints).

I am thinking of many setups where people (& me) have a VGA/DVI monitor and desktop PC speakers. HDMI to DVI no problem, but having or the ability to solder on a 3.5mm jack will open up more options to use the Flea.

Also regarding the USB ports, PS/2 is mentioned . Could you be clearer. With Next186 and Minimig, you can use USB joystick, keyboard and mouse? (OK on Next186 USB joystick might be pushing it).
I am not sure and other potential backers may also not be sure what can be used.
Finally can a USB hub be plugged in? Again just to ease any concerns. 2 ports onboard is good but for an AMIGA to be truely useful you need 3 (keyboard, mouse and joystick).

I think you know, but to clarify, I am not being negative, just trying to help your campaign and highlight things which might not be obvious to a project creator but are a bit confusing to potential backers.

Thanks

[Basman74]

Also regarding the USB ports, PS/2 is mentioned . Could you be clearer. With Next186 and Minimig, you can use USB joystick, keyboard and mouse? (OK on Next186 USB joystick might be pushing it).I am not sure and other potential backers may also not be sure what can be used.

Sure! Would be happy to.

Both the Next186 and Minimig cores shown in my Indiegogo video, are direct ports of existing projects on opencores or github. Both cores (in their current form) will only talk to PS/2 devices (hence why I also made the ports backwards compatible with PS/2). So, in order to use either of these cores one must use either composite USB (ie. devices that can fall back to PS/2) or be PS/2 only connected via some adapter dongle.

While the two micro USB host ports have been designed with a focus on direct connection HID class devices, actual HDL examples for this are very much in the 'pending' stage. Obviously, both of the above-mentioned cores could benefit from USB HID support and the provisions are on-board electrically speaking.

Now, given my personal free time is limited (this is a hobby project, after all), my current plan going forward:
1.) Ensure those ports will be suited to their various modes and then get as many boards into the hands of people who know as much (or more) about USB than I do.
2.) Where possible, and get at least one form of working USB HID related example ready around the time the Ohm boards ship.

There are many different retro computer systems and/or game consoles my FleaFPGA Ohm could implement, potentially. While HDL development can be fun (my opinion) but also can be very time-consuming for complex HDL conversions, hence plan task#1 takes priority.

Finally can a USB hub be plugged in? Again just to ease any concerns. 2 ports onboard is good but for an AMIGA to be truely useful you need 3 (keyboard, mouse and joystick).

While possible, a USB Hub negotiation adds an extra level of complexity I would prefer not to deal with quite frankly. So this is not an option I'll be looking into in the short/medium term (but I won't stop anyone else from doing so if they wish!).

In my view, GPIO for joysticks or one USB joystick per port would suffice for gaming console applications for FleaFPGA Ohm.

I think you know, but to clarify, I am not being negative, just trying to help your campaign and highlight things which might not be obvious to a project creator but are a bit confusing to potential backers.

No problem. I think it helps if I re-iterate what I attempted to make clear in terms of what was on offer on Indiegogo: I am effectively offering a fairly low-cost FPGA development board with what appears to be some possibilities for things like retro-gaming. My campaign only covers the cost to make and ship tested boards that also have some existing working examples to go with them on github. Anything above that must happen in the remainder of my free time or ask for additional help. To be honest the latter would be well appreciated.

I hope this is clear.

Regards,
Valentin

[kolla]

When plugged into a raspberry pi (zero), how... uhm... integrated are the two?
I am again imaging FPGA accelerated emulation, where ARM on Pi do CPU emulation, fast ram and I/O, while Flea Ohm has the chipset and chipram covered.

Hope the keyboard issue can be sorted, so many old games just take for granted that Amiga has keyboard

[christos]

Just a quick question. This doesn't run the Atari ST core, right?

[Basman74]

When plugged into a raspberry pi (zero), how... uhm... integrated are the two? I am again imaging FPGA accelerated emulation, where ARM on Pi do CPU emulation, fast ram and I/O, while Flea Ohm has the chipset and chipram covered.

Well, for starters the GPIO headers are electrically pin-compatible (I think I mention that already in the basic specs on the campaign page and elsewhere). This provides various interfacing options. As for programming the FPGA from the pi zero, one could conceivably connect the USB OTG host from pi zero to flea Ohm's USB slave port and run a ported variant of flea JTAG utility on the Pi zero to load bit-files into the FPGA's config SRAM on the Ohm board..

I am currently working on a User manual for FleaFPGA Ohm right now. Kindly keep an eye out for it if you're interested.

Cheers, Valentin

[Basman74]

Just a quick question. This doesn't run the Atari ST core, right?

It could, but nothing has yet been ported to my board. I suppose if it can do Amiga then I'm reasonably sure it could handle an ST machine as well.

[Sorgelig]

Just a quick question. This doesn't run the Atari ST core, right?

It could, but nothing has yet been ported to my board. I suppose if it can do Amiga then I'm reasonably sure it could handle an ST machine as well.

Is MCU part of Minimig running on softCPU core?
Is there any menu where you can choose what core to load or is it single core board?

[Basman74]

Is MCU part of Minimig running on softCPU core?
Is there any menu where you can choose what core to load or is it single core board?

@Sorgelig: Thanks for your questions!

I assume you mean the MCU that handles the SDcard interfacing? I use a 2nd TG68 softCPU to handle that.

Also, it is mainly intended as a single-bitfile board. However, there are a few potential ways to extend functionality to multiple cores. This could be done by using an external MCU/MPU on a either custom 'hat' (that taps into the 6-pin JTAG header on the board) or via the FleaFPGA Ohm's USB slave port. These could, in theory, update the SRAM config array of the ECP5 FPGA. Tapping into the on-board 6-pin JTAG header would be the faster of the two, I believe.

Regards,
Valentin

[Higgy]

Congratulations on hitting your target!

I don't know the tech details so this might not be relevant at all and you might have seen this, but the standard ZX Uno has a 8mbit SPI Winbond flash for Core storage. They have a menu that you can enter to change Cores. As with a lot of these things the code is available. Main website is here:

http://zxuno.speccy.org/maquina_e.shtml

[Basman74]

Congratulations on hitting your target!

Thanks. Soon the 'fun' begins for me to make the boards happen!

I don't know the tech details so this might not be relevant at all and you might have seen this, but the standard ZX Uno has a 8mbit SPI Winbond flash for Core storage. They have a menu that you can enter to change Cores. As with a lot of these things the code is available. Main website is here: http://zxuno.speccy.org/maquina_e.shtml

Thanks for the suggestion. Their method isn't ideal for the Ohm board (need to cycle power after re-programming external Flash ROM, among other things..).

In any case, updating the FPGA config ROM contents on FleaFPGA Ohm via USB from a PC is quite straightforward and already doable from either Windows or Linux. Not to mention the possibility of writing directly to FPGA config SRAM (which does not need power cycling afterward) from an external microcontroller or even a Pi Zero via JTAG as mentioned previously.

Regards,
Valentin

[kolla]

The screenshot above shows a super hires laced mode - I never managed to display any laced modes with the FleaFPGA Ohm, I just get “no signal” when I try. What’s the secret?

[Basman74]

The screenshot above shows a super hires laced mode - I never managed to display any laced modes with the FleaFPGA Ohm, I just get “no signal” when I try. What’s the secret?

I'll answer your question with a question: Can you explain to me, why did you fork copyrighted material on Github without asking? You did not reply to my email regarding it so I am asking here.

Depending on your reply, I will consider helping you with your question.

- Valentin

[Basman74]

@kolla,

Thanks for responding to my email. Regarding your question, two things you'll need in order to generate the above 'super-hires' PAL screenshot:

1.) a Display client (i.e. TV/monitor) that supports interlaced PAL/NTSC screen modes via digital video inputs, as well as the non-standard video timing provided by minimig.

2.) Have the '30/15kHz video select' pin tied to ground on your FleaFPGA Ohm as shown in pinout drawing at the end of my ECS setup guide included in the minimig ECS repo on Github.

Hope this helps,

Valentin

[kolla]

@Basman74

You should be aware of this:
https://docs.github.com/en/github/site- ... ther-users

And if you after reading that decide to remove you repo… that would be the answer to your question to me about “why”

[Basman74]

@kolla

Thanks for your answer. That doesn't automatically revoke my rights to said documentation but I understand your explanation. In any case, I was never entirely happy with hosting the manual on Github so I have uploaded a new repo in modified form.

- Valentin