Review (Part 1) of the MiniMig Amiga 500 clone.

[ral-clan]

A fellow has posted a pictorial review (well, just part one) of the Minimig (an Amiga 500 open source clone).

I'm pretty impressed with how small it is. Also the fact that it uses flash cards and standard VGA monitors (no flicker fixer needed) is a big bonus.

I'm hoping the development evolution of this thing eventually leads to clones of more powerful Amiga systems, like 040 and even 060 machines.

http://www.loriano.pwp.blueyonder.co.uk ... mig_v1.htm

Anyway, you have to keep clicking on the "NEXT" link on each of those pages to see the rest of the review.

[MacbthPSW]

I guess I'll see when he finishes the review, but if this board is pretty much plug & play then I think I'm getting one. Looks like you can just plug in your keyboard, mouse, monitor, get an SD card properly configured, and away you go?

And, could this be a good hardware platform for VIC-20 and C-64 cores as well (if someone is willing to put in the work, of course)? If so, and they made a version with IEC right on board, this could sell really well.

[Boray]

How about amiga 880kb floppy disks?

[ral-clan]

I guess I'll see when he finishes the review, but if this board is pretty much plug & play then I think I'm getting one. Looks like you can just plug in your keyboard, mouse, monitor, get an SD card properly configured, and away you go?

And, could this be a good hardware platform for VIC-20 and C-64 cores as well (if someone is willing to put in the work, of course)? If so, and they made a version with IEC right on board, this could sell really well.

I don't know much about the technical aspects of the MiniMig, but I have read some discussion about how this could be used to emulate other old computers systems.

As for plug-and-play. I think it mostly is, but I also remember reading somewhere that you need to install the Kickstart image or something - as they don't have the rights to distribute that.

Also, I think the system has been designed to think it's a PAL Amiga. There hasn't been an NTSC version of the MINIMIG "core" written yet (it's apparently quite possible, just that no-one has bothered yet). The output isn't really PAL (as it's double scanned to VGA scanrates), but NTSC games might look squished. I don't think this is really any problem for N. American users using a Minimig, but just something to know in advance.

To Boray: no it can't use 880Kb discs as far as I know. But you can DMS or ADF all your 880KB discs and fit hundreds of them on an SD flash card to use in the MiniMig.

[Centallica]

Very nice piece of equiment

$205 Canadian plus shipping for non-kit...very tempting....must resist for now and wait for later board revisions too

I'd like to follow this project too and see what else comes of it. Would be nice for a Vic or C64 one too eventually

[ral-clan]

Part two of the review has been put online:

http://www.loriano.pwp.blueyonder.co.uk/Part_Two.htm

[gklinger]

The thing about the MiniMig is that it's just a hardware emulator and I don't see what advantages it provides over software emulation. I was amused that the reviewer refers to the compatibility as being "Almost 100%" and yet more than 1/3 of the software they tried didn't work. I'll stick with my E-UAE and my Amiga 1200 for now (and that's saying something because I love spending money on crap like the MiniMig).

[ral-clan]

The thing about the MiniMig is that it's just a hardware emulator and I don't see what advantages it provides over software emulation. I was amused that the reviewer refers to the compatibility as being "Almost 100%" and yet more than 1/3 of the software they tried didn't work. I'll stick with my E-UAE and my Amiga 1200 for now (and that's saying something because I love spending money on crap like the MiniMig).

That's what I wonder too. Isn't it just another form of emulation? But I guess some argue that it's not because it's an FPGA re-creation of the chipset. Also, they are using a real 68000 there too, so that would be a big advantage over emulation.

Perhaps this makes the experience smoother and more like a real Amiga 500.

[gklinger]

But I guess some argue that it's not because it's an FPGA re-creation of the chipset.

That's the important and difficult part.

Also, they are using a real 68000 there too, so that would be a big advantage over emulation.

Emulation of the 68000 is 100%. Emulation isn't perfect because of the emulation of the custom chips.

One other thing. Everyone knows they can make their own Minimig, right?

[ral-clan]

But I guess some argue that it's not because it's an FPGA re-creation of the chipset.

That's the important and difficult part.

Also, they are using a real 68000 there too, so that would be a big advantage over emulation.

Emulation of the 68000 is 100%. Emulation isn't perfect because of the emulation of the custom chips.

One other thing. Everyone knows they can make their own Minimig, right?

Yeah, I knew the Minimig has been available as a bare board (for kit buildings) for a long time. Now it's available as a finished product though.

As for 68000 emulation being perfect. That's true no doubt. But I think that there are still "timing" issues in emulation. i.e. even though you put instruction A into the emulated 68000 and the output is exactly the same as a real 68000, the timing of that instruction might not be right. This is because the emulated 68000 is running on top of another OS or another microprocessor, which also has a lot of other work to do. There are tiny differences which make for a slightly different feel in game play, etc.

I can certainly notice it when I use an emulated VIC or C64 (I realise those are not 100% perfectly emulated yet).

I won't use an emulated Amiga to run any MIDI music software because of that. I'd rather use a real A500 than a much faster emulated system. In music, the timing must be dead-on. Emulation really shows off its shortcomings when dealing with timing critical issues such as music software.

In this case, if the Minimig is a lot closer to a real Amiga 500 in timing, etc. I'd be much more inclined to buy one (or a future Minimig 2000, 3000 or 4000) to replace my aging real Amiga hardware in my home recording "studio".

[MacbthPSW]

I think it's more accurate to call it a clone when it's a hardware based "emulation". Whether it's an accurate clone or not is another matter.

[eslapion]

I think it's more accurate to call it a clone when it's a hardware based "emulation". Whether it's an accurate clone or not is another matter.

I agree. This is not emulation, this is an attempt at replication. Replication is far more difficult than emulation.

You have much more stringent timing constraint when replication than when emulating and that's probably why less software runs well on the minimig than an emulator, and that's because its really trying to reproduce the original thing down to low level details.

Also, concerning the 68000, I noticed a few months ago on Amiga.org that a guy names Tobias made a 68000 core for FPGA and was able to integrate the Minimig VHDL with that core and run the whole thing, free of the Motorola chip on a DE2 Altera educational board.

[eslapion]

...
And, could this be a good hardware platform for VIC-20 and C-64 cores as well (if someone is willing to put in the work, of course)? If so, and they made a version with IEC right on board, this could sell really well.

I suppose it would be relatively easy to adapt MikeJ's VHDL VIC to that platform...

Unfortunately, MikeJ has made it clear he has no intent in investing the time to make his FPGA based VIC NTSC compatible... PAL only is the norm right now.

[nippur72]

I'm thinking about getting one Minimig. Other than playing Amiga, it's the perfect platform for a VIC-20 FPGA implementation. The board cost less than the Xlinix Spartan-3E alone, plus it has 1GB SD memory and does not need modification for the video (Spartan-3E does, because has 1-bit color).

My intention would be 1) learning Verilog language, 2) translating MikeJ's VHDL code into Verilog (I just can't stand VHDL!) and 3) adapting it to Minimig, possibly expanding its features.

Learning to program an FPGA could be a new exicting adventure. Plus add the fun of going in depth into VIC-20's architecture!

But, there are some cons. Minimig comes with no JTAG cable (the one you use to program the chip) so you need to program it by putting the configuration file on the SD card. Alas, I don't have a SD card reader for my PC!

Minimig also has lacks some ports present on the Spartan 3-E, like Ethernet.

Also there is no FPGA programming software included... I wonder if the Xilinx free WebPack is able to produce a valid configuration file for the Minimig.

Last con is that I would be a newbie in the field, so completing the project I have in mind could take a very long time.

Please share any insights/suggestion you have on the subject.

[PaulQ]

It essentially replaces an Amiga 500, right?

Last time I checked, A500's were still relatively cheap and easy to come by, but offer 100% compatibility.