TG68 - The Open Source Minimig CPU into the FPGA

[amigadave]

freqmax wrote:
@Belial6:
Or you could use: http://www.xess.com/prod035.php3

Which have 2,5 times logic array of XC3S400. Should be enough for Minimig + MC68000. Builtin PS/2 port, VGA, RAM.
MMC interface, Sound etc.. can be added with some very simple circuit to the prototyping header.

That looks like a very cool prototyping board and components.  Is it really true that it has insufficient lines going to the VGA port for Amiga graphics or did I skim this thread too quickly and misunderstand the comments?

[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!

[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?

[amigadave]

@Belial6,

Thanks for the reply, but from what I have read so far, it did not appear to me that Dennis and Tobiflex are arguing.

My understanding is that the DE1 board just barely is capable of running Minimig v1.1 and has no capacity for improvements which is where many others, including Dennis want to go (v2.0 and beyond).  Maybe I am wrong and have misunderstood some of the previous messages that I read too quickly, but I am pretty sure that Dennis is interested in v2.0 and less interested in just porting v1.1 to other boards.

In any case, I still like freqmax's suggested board, but have not checked on what it cost, I'll go back and look it up and try checking for pricing?  Perhaps someone besides Tobiflex or Dennis will take enough interest in it to try to port the Minimig code, open core 68000 code and some other enhancements to it in the near future.

@Tonyeb, that is what is so exciting about the work being done on the Minimig project.  It has "legs" and anyone with the skill and desire can take what has already been done by Dennis and Tobias and "RUN" with it to create a bigger and better project.

[amigadave]

freqmax wrote:(edited)
Or you could use: http://www.xess.com/prod035.php3

1 million gate FPGA plus all the features below for $199

Features:

    * XC3S1000 FPGA
    * XC9572XL CPLD
    * 32 MByte SDRAM
    * 2 MByte Flash
    * 100 MHz oscillator
    * Parallel port
    * Keyboard/mouse PS/2 port
    * 512-color VGA port
    * 7-segment LED
    * 2 pushbuttons
    * 4 DIP switches
    * 84-pin prototyping interface (65 free I/O pins)
    * 5V DC power jack
    * 5V / 3.3V / 2.5V / 1.2V regulators
    * Downloading cable
    * XSTOOLs CD
    * Works with XILINX ISE, WebPACK, iMPACT and ChipScope software
    * Requires Win2K or WinXP. Not supported by Win98 or WinME!

Looks very tempting to me at that price.  I hope someone attempts to get the Minimig running on it and an open core soft 68020+ is created to put in it.  (I wonder how long it would take me to learn Verilog and VDHL?) :lol:  (probably pretty long since it is VHDL, not VDHL)

Oh, and don't forget this is included too!

Documentation:

    * XSA-3S1000 Board Manual (PDF file)
    * XSA-3S1000 Board Pin List (Excel file)

And these are available:

Accessories:

    * XSUSB USB interface
    * XStend Board 3.0
    * 5 VDC power supply (North America)
    * 5 VDC power supply (Europe)

[amigadave]

@freqmax,

I liked your first suggestion much better, and for an A1200 like Minimig, the 32mb RAM should be plenty.  I am sure it is going to take a huge amount of developing effort to get from v1.1 OCS to v3.x AGA w/68020+ soft CPU.  Perhaps as much, or more than Dennis had to put into the whole of his design?  It would be great if a small team of programmers would take it on and speed its completion.  A Minimig that is equivalent to an 030/50mHz A1200 in a small form factor and at a cost of $300 to $450 would be quite an accomplishment.

[amigadave]

@downix,

Not being as tech savvy as you, I have no idea how many gates the FPGA would need to do the AGA Minimig code plus a softcore 68020+ and thought the 1 million gates could maybe do it.

The price of $199 for the 1 million gates plus all the other features seems like a very good price and it has expansion capabilities which could perhaps contain either the 68020+ in another FPGA, or the AGA, or better display device code.  I just thought that for the price, there was a lot going for the XSA-3S1000 Spartan 3 Prototyping Board and since price is a big consideration for many wanting a Minimig, the XSA-3S1000 was worth looking at a little closer by someone with the capability to produce something.

So, I brought it up a few times just in case it would help point it out to the right people.

Oh, and I totally agree that ECS needs to be next and you are right that we must walk before we can run.  I know that AGA and/or 68020+ will likely be a year or more into the future.

@FrenchShark,

Sounds like a great plan, are you going to be working alone, or with others to make it a reality?  The reason I ask is that I hope that the huge effort to create AGA and/or 68020+ softcore code is at least done in cooperation and not several individuals working on the same thing at the same time and having it take many times as long to complete as it would if they work together.

@Dennis,

See what you have started!  My congratulations to you again sir.  You have done more for the Amiga community than any single person since Jay Miner.    :bow:

[amigadave]

jkonstan wrote:
The Stratix II development board sounds like a nice idea; however, it is really expensive right now ($2K to $3K) unless you have access to one via work or school. Affordable FPGA evaluation boards today, would be Altera Cyclone II/III or Xilinx Spartan 3e.

 :-)

My point about cost and the XSA-3S1000.

[amigadave]

eslapion wrote:

amigadave wrote:

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 Amiga OCS displays 16 or 32 colors out of a palette of 4096 colors. HAM mode can use all 4096 colors on a single picture.

That's because the OCS has 4 bits of final digital output on all 3 Red, Green and Blue channels. 3 x 4 =12 total bits to control the color of every individual pixels 2^12=4096.

The aforementioned board has bits numbered 0 to 2 on these 3 channels. 0 to 2 means 3 bits per channel 3x3=9 bits per pixel on the final output. and 2^9=512.

Yes, I know all about how the Amiga OCS uses a palette of 4096 colors and can display them all in Hold And Modify.  What I had not done was the math using only 3 bitplanes to come up with the 512 color limit (I somehow thought it was a different number).  Anyway, I wonder if the XSA-351000 Spartan 3 Proto-Typing board's 512 color palette would work for all other Amiga programs that don't use HAM mode.  I don't know of any games that do (but there are probably a couple).

DCTV only uses 3 bitplanes per color and can output millions of colors to composite output and even has an RGB converter to display all those colors back in RGB mode.  I would love to go down that route and have the capabilities of the DCTV reverse engineered into the Minimig, or to add a DCTV to the XSA-351000 board's expansion port somehow and have an Amiga display of millions of colors natively using only 3 bitplanes and such a low amount of display power it would be very fast.