TG68 - The Open Source Minimig CPU into the FPGA

[ChaosLord]

@TobiFlex

Is your fpga 680x0 using a barrel shifter for shifts and rotates?

[amigadave]

Great news Tobiflex, congratulations and thank you!

Dennis wrote:
Excellent news!!

This opens up some whole new possibilities...
(pondering about Minimig rev2.0  :-D )

What a great bit of other news to see that the famous Dennis van Weeren himself is still thinking of Minimig rev2.0 and has not gone on to other unrelated (non-Amiga) projects.

I know Tobiflex has said it would be difficult to move from 68000 to 68020 and above, but I hope that it does not prove to be so difficult that it is not attempted by someone, or another solution is found to lead the Minimig version path up to and beyond all Classic Amigas performance eventually, without breaking backward compatibility.  Perhaps the future versions of the Minimig will even be more compatible at running old AND newer Amiga software than real Classic Amigas?

Very exciting times in the long history of the Amiga!

Dennis, Tobias, ........... Never Give UP!  Never Surrender!

[Belial6]

I'm not sure what all of the debate is about.  TobiFlex says that he already has MiniMig running on a DE-1 board.  Earlier in this thread, he said it works, but he has a few tweaks that still need to be worked out.

I and one other user at least have offered buy Dennis a DE-1 board so that Dennis and TobiFlex can work from a common platform.  If Dennis responds back telling me that the DE-1 will not work, I will withdraw my offer.  If he says that it will work, and accepts the offer, I will buy a board that will be shipped to him.

No matter how much the rest of you argue about what the best board for the project is, only two people have really produced anything that would qualify them as proven experts.  One of the two (TobiFlex) has already stated his endorsement of the DE-1 board, which is inexpensive, and we have not heard from the other.

Now, I don't want to discourage any of you from proving your expertise by porting to an even better board with greater capabilities, but until the time that Dennis comes forward and says that TobiFlex is our of his mind, I am going to take TobiFlex at his word that the DE-1 is up to the job.  Even if he does, I will wait and see if TobiFlex could prove him wrong.

I don't think there is anyone out there that will complain if they can buy a professionally produced MiniMig for $150.

[ChaosLord]

@Belial

Just so you know: from what I can tell, the DE1 needs some add-ons, so the cost will be more than $150.00.  So don't be shocked when the final cost comes in. Good luck. :-)

[freqmax]

@amigadave:
The board doesn't have lines to display *all* colours of the Amiga. Ie max 512 colours.
But this doesn't prevent it from running minimig. And should more fance colouring scheme be desired. One can always add something on the prototyping header. With throughhole stuff (easier).
The important thing is that it has onboard RAM (32M) and that now when the cpu + custom circuits can all be done in HDL. All the messy SMD soldering can be done away with.

[Belial6]

@ChaosLord

Instead of guessing, why not just ask TobiFlex?  He has already ported MiniMig to the DE-1.

[amigadave]

freqmax wrote:
@amigadave:
The board doesn't have lines to display *all* colours of the Amiga. Ie max 512 colours.
But this doesn't prevent it from running minimig. And should more fance colouring scheme be desired. One can always add something on the prototyping header. With throughhole stuff (easier).
The important thing is that it has onboard RAM (32M) and that now when the cpu + custom circuits can all be done in HDL. All the messy SMD soldering can be done away with.

512 colours (or as we would write over here, colors)?  I don't understand that limit, but most Amiga software only requires 16 or 32 colors and productivity usually will work fine with only 4 colors.  The onboard 32mb RAM and extra capacity of the FGPA, plus all the other features makes it seem like a good candidate for Minimig v1.2 without having to solder anything.  That plus the added advantage of the expansion connections could lead to more development and addons.

I wonder if Dennis and Tobias have looked at it?

[Belial6]

@AmigaDave

TobiFlex has stated earlier in this thread that he has already ported MiniMig to the DE-1 and is just tweaking a few things before releasing it.  He also suggested that Dennis work on this board.

This is why I don't get what the debate is about.  Everyone arguing against this board are not arguing that the effort should be put somewhere else.  The effort has already been done by TobiFlex.  They are arguing that TobiFlex should just not release the code because they think a different, and generally WAY more expensive board would be better.  It makes no sense.

The other point that they are arguing is that Dennis should not be working on a common platform as TobiFlex, as both sweetlilmre and I have each offered to individually pay for the entire cost of a DE-1 board for Dennis.

I truly do not understand where these people are coming from.  Maybe they are just so used to not having access to new hardware, that they don't know how to deal with it.  Maybe they are worried that they will lose that little thing that makes them special if just anybody can buy Amiga compatible hardware.

[TobiFlex]

I wonder if Dennis and Tobias have looked at it?

Yes I have. But I can not seen a advantage.
The other point: I love Quartus - The Altera FPGA Design Software - especial the integrated Logic Analyser "SignalTap II". He is also included into the Web Edition. I have found many Bugs with the help of "SignalTap II".


   

@ ChaosLord
Is your fpga 680x0 using a barrel shifter for shifts and rotates?

Use a real 68000 a barrel shifter?
NO!
So I also not use a barrel shifter in my Core.

@alexh
I am sure TobiFlex could get the size of the TG68 down abit with some good constraints and if he made some of the instructions multi-cycle.

I will not optimize the size next time.
I will only optimize the function and speed next time and I think I need more LCs for the optimized Design.

[alexh]

TobiFlex wrote:
I will not optimize the size next time.
I will only optimize the function and speed next time and I think I need more LCs for the optimized Design.

As Jens Schoenfeld of Clone-A said (and from experience I agree) when reverse engineering, the more you improve compatibility the smaller the design sometimes gets. You start to get closer to the original design which was inherently smaller.

Good luck and as soon as I get a board I'll help out a bit. Come on Crom!

[TobiFlex]

I should use a "one hot State Machine" for the signal "microaddr". This could bee an effect.

[TobiFlex]

Hi,
The first update for the TG68 Core:

Open Source 68000 IP Core

I have added the MOVEP Instruction and found a Bug in MOVEQ. If MOVEQ was interrupted the data never stored into the Register.
Now is the Floppy Emu also stable. It was the CPU Core Bug!
Now I can compile stable versions for the DE1 and DE2 Board :-)

The CHK Instruction is not so difficult - but I must make some changes into the Trap system  and this IS difficult :-(

[tonyyeb]

This is all very exciting and obvioulsy the work done is fantastic.... but can someone explain why a simpleton like me who just wants a Minimig and future Minimig developments to continue... should be getting excited?

Thanks in advance

[alexh]

tonyyeb wrote:
can someone explain why a simpleton like me who just wants a Minimig and future Minimig developments to continue... should be getting excited?

If you have a MiniMig v1.x board you dont care.

If are a potential MiniMig v1.x owner, but cannot find one cos no one makes them, and were considering getting buying one of the slightly expensive off the shelf Altera DE1 or DE2 boards then you are wetting your pants as a more compatible DEx-MiniMig is on it's way.

[Crumb]

but can someone explain why a simpleton like me who just wants a Minimig and future Minimig developments to continue... should be getting excited?

This minimig version will also share custom chip emulation with MiniMig v1.x.

[tonyyeb]

alexh wrote:
If you have a MiniMig v1.x board you dont care.

If are a potential MiniMig v1.x owner, but cannot find one cos no one makes them, and were considering getting buying one of the slightly expensive off the shelf Altera DE1 or DE2 boards then you are wetting your pants as a more compatible DEx-MiniMig is on it's way.

So what will be the future? I buy a dev board and then i can download new code and use Amiga software on it?