FPGA 68000

Moderators: Mug UK, Zorro 2, Greenious, spiny, Moderator Team

User avatar
SainT
Obsessive compulsive Atari behavior
Obsessive compulsive Atari behavior
Posts: 116
Joined: Tue Dec 04, 2007 3:33 pm
Location: Gloucestershire

FPGA 68000

Postby SainT » Tue Feb 12, 2008 9:59 am

I'm thinking about getting an FPGA board to have a mess around with some 68000 based hardware hacking, does anyone have any suggestions for something fairly cheap which has enough gates to run something like an ST? I was looking at the Spartan-3 with a XC3S400 (http://www.enterpoint.co.uk/store/erol.html#2045X2108) -- is 400k gates enough? I know the old 68000 allegedly had 68k gates, but something tells me the synthisised cores available are likely to be bigger.

Cheers
-- James

matashen
Atari nerd
Atari nerd
Posts: 46
Joined: Wed Oct 31, 2007 8:06 pm

Re: FPGA 68000

Postby matashen » Tue Feb 12, 2008 4:25 pm

Hello,

Contact Wolfgang Förster at experiment-s.de
He already works on an FPGA-AtariST Core called Suska III

He has the VHDL Code of that project online on his site

Greatings Matthias

User avatar
SainT
Obsessive compulsive Atari behavior
Obsessive compulsive Atari behavior
Posts: 116
Joined: Tue Dec 04, 2007 3:33 pm
Location: Gloucestershire

Re: FPGA 68000

Postby SainT » Tue Feb 12, 2008 4:29 pm

Yeah, the Suska project is what got me interested in the first place. There is also some interesting work on old arcade games, C64, Amstrad CPC and so on... FGPA's are interesting bits of kit.

I'll drop him a line...

-- James

User avatar
alexh
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2595
Joined: Wed Oct 20, 2004 1:52 pm
Location: UK - Oxford
Contact:

Re: FPGA 68000

Postby alexh » Wed Feb 13, 2008 2:10 pm

If you want an FPGA board, may as well get a MiniMig

http://www.vesalia.de/e_minimig.htm

MiniMig has the advantage of having a 68k CPU soldered down (freeing up room in the FPGA for the main chipset). It's two main faults are the RAM, there is only 2Mbytes of which (256Kbytes) is used by TOS. The other is it only has 12-bit (4096) colour output (But to be fair, that is better than some FPGA boards!). But it does have an example of a scandoubler (31KHz VGA output stage). It does have VGA connector, Joysticks, mouse, keyboard. It has an example of a floppy disk emulator written in PIC assembler (reads data files from the MMC/SD card and pretends to be a floppy drive).

http://home.hetnet.nl/~weeren001/

As has already been said, most of the work for the Atari ST has been *attempted* (not to say it is any good).

http://www.experiment-s.de/index.php?id=78&L=1

Of course MiniMig (like all FPGA boards) can be programmed to represent other platforms, Spectrum, Amstrad, C64 have all been converted to RTL (hardware source code).

http://home.freeuk.com/fpgaarcade/index.htm
http://c64upgra.de/c-one/
http://www.symbos.de/trex.htm
http://zxgate.sourceforge.net/index.html

If you need any help, just ask. Programming in VHDL and Verilog and using FPGA's is my Job, that is what I did over in ARC at Argonaut, been doing it ever since.

User avatar
alexh
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2595
Joined: Wed Oct 20, 2004 1:52 pm
Location: UK - Oxford
Contact:

Re: FPGA 68000

Postby alexh » Fri Feb 15, 2008 3:29 pm

MiniMig's FPGA is programmed in circuit from a file which is on the SD card. The program on the PIC microcontroller reads the SD card and programs the FPGA on power up. If you want to change anything you recompile, route, copy the file onto the SD card and then power cycle.

Another (sort of) negative of MiniMig is the PIC. Unlike the FPGA it cannot be programmed in circuit. If you want to make any changes to the PIC program you need an external PIC programmer.

What is the PIC used for?

It is an intermediary between the FPGA and the SD card.

  • It programs the FPGA.
  • Allows you to select which floppy disk image to "insert"(With an OSD-GUI)
  • Emulates the floppy disk drive
  • In the future it will emulate hard disk drives (either using image files, or a DIR)

simbo

Re: FPGA 68000

Postby simbo » Fri Feb 15, 2008 4:06 pm

hi alexh ive done this in the past

you can connect just two 220R resisistors in series usualy with B5 and B6 and !mclr pins on any pic
and at the pin end connect just three wires

and program flash it from icprog.exe even if it has no bootloader over the serial port
adding fly programming this way is easy to any existing pic circuit
then you just need a serial port rx tx cls wire dtr with dsr in the serial plug
and thats it can even be a drag and drop to flash the new file so fly programming is also aok

i toyed with the idea of getting one of these but ill wait a while see what happens myself
... it is nice and looks fab....

User avatar
alexh
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2595
Joined: Wed Oct 20, 2004 1:52 pm
Location: UK - Oxford
Contact:

Re: FPGA 68000

Postby alexh » Fri Feb 15, 2008 9:49 pm

The £120 MiniMig cost is still a bit offensive. Especially as you can pick up an XBOX-1 for £20 and run emulators.

Hopefully the MiniMig price could come down with enough sales.

It's a shame, the MiniMig board is just not quite good enough: It's too expensive, the FPGA is a little on the small size (offset with hard 68k), it only has 12-bit colour (Amiga 1200 & Atari Falcon's have 24-bit), and the worst thing it only has 2Mbyte RAM (1.75 usable).

If it was just remade with a few tweaks it would be perfect.

But MiniMig is a lot cheaper than the alternatives:

http://www.terasic.com.tw/

The DE-2 board is better, but too expensive and OTT with Ethernet and USB, even TV-IN. Strangely it only has 10-bit colour!

User avatar
earx
Captain Atari
Captain Atari
Posts: 353
Joined: Wed Aug 27, 2003 7:09 am

Re: FPGA 68000

Postby earx » Tue Feb 19, 2008 8:43 am

Falcon has 18 bit colour in planar mode and 16 bit when in chunky mode. A1200 had 24 bit IIRC. chunky mode was way more useful, anyhow. </pedantic>

User avatar
unseenmenace
Atari God
Atari God
Posts: 1961
Joined: Tue Sep 21, 2004 9:33 pm
Location: Margate, Kent, UK
Contact:

Re: FPGA 68000

Postby unseenmenace » Tue Feb 19, 2008 10:45 am

It would be awesome to see an FPGA STE with all the major ports as a proper ST replacement. You could even attach a small LCD and some buttons and make it into a PST :) I'm not sure it would be worthwhile to emulate anything above a Mega STE though so surely 4MB RAM and 12-bit colour would be fine?
UNSEEN MENACE
Several STFM's, 4MB STE, 2MB TT with 1.2GB Hard Drive and 14MB Falcon with 540MB Hard Drive,
Lynx 2 and Jaguar with JagCD
Member of GamebaseST and AtariLegend team
Check out my website at http://unseenmenace.110mb.com

User avatar
alexh
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2595
Joined: Wed Oct 20, 2004 1:52 pm
Location: UK - Oxford
Contact:

Re: FPGA 68000

Postby alexh » Wed Feb 20, 2008 5:09 pm

The MiniMig PCB is ideal (if a bit expensive at £120) for reproducing a 1Mbyte Atari ST(e). It's bonus features (over a £10 ST) are 31KHz VGA output, PS2 keyboard and mouse, no floppy drive or disks and it's form factor.

It would take about 1-2 hrs to merge the VHDL Suska sources with the MiniMig PCB VHDL wrapper to get it to working (in the most basic form).

A week or so to complete the merge, then perhaps a lifetime to debug ;)

User avatar
Joel
Obsessive compulsive Atari behavior
Obsessive compulsive Atari behavior
Posts: 107
Joined: Thu Mar 01, 2007 12:42 am
Location: Essex, UK

Re: FPGA 68000

Postby Joel » Sat Feb 23, 2008 5:56 pm

Well if someone was willing to have a crack at that I'd be happy to bug test it.

I have two Minimig bare PCBs left from my run over on amiga.org so I could populate both and send one to the prospective coder willing to take on the task (I'm looking at you alexh :D). Of course the programmer could keep the PCB after.

I have a source in China for the parts too, at least the hard to find components.

Incidently, wouldn't you just be able to swap out the two 1mb RAMs for two 2mb chips and update the code? Don't they work like eproms?

-Joel
520 STFM (Upgraded to 1mb)
520 STFM (Stock)
520 STFM (Stock)
1040 STE (Stock)
Falcon 030.. I wish!

User avatar
alexh
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2595
Joined: Wed Oct 20, 2004 1:52 pm
Location: UK - Oxford
Contact:

Re: FPGA 68000

Postby alexh » Sat Feb 23, 2008 10:36 pm

Joel wrote:I could populate both and send one to the prospective coder willing to take on the task (I'm looking at you alexh )

Get me a debugged board and I am more than happy to do the work. I was thinking of contacting A-Cube direct.

Joel wrote:Incidently, wouldn't you just be able to swap out the two 1mb RAMs for two 2mb chips and update the code?

I think you would need additional pins on the FPGA between the 68k and SRAM for the extra address line. Exactly how many? Not sure. At least 2 (1 in and 1 out) as the address lines feed through the FPGA.

Can you get 2Mbyte chips?
Last edited by alexh on Sat Feb 23, 2008 10:43 pm, edited 1 time in total.

User avatar
alexh
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2595
Joined: Wed Oct 20, 2004 1:52 pm
Location: UK - Oxford
Contact:

Re: FPGA 68000

Postby alexh » Sat Feb 23, 2008 10:41 pm

I wonder what is the state of the Suska code? I am suprised we've not seen Tobiflex port Suska to the TerASIC DE boards. He's done MiniMig and Amstrad CPC. Maybe it's not in as good a state as the archive suggests.

User avatar
Joel
Obsessive compulsive Atari behavior
Obsessive compulsive Atari behavior
Posts: 107
Joined: Thu Mar 01, 2007 12:42 am
Location: Essex, UK

Re: FPGA 68000

Postby Joel » Sun Feb 24, 2008 5:03 pm

Get me a debugged board and I am more than happy to do the work. I was thinking of contacting A-Cube direct.


Their price is a little over what I'd be paying for components. Plus these have been sitting here a while so better they get put to use than sit there any longer!

You can get up to at least 4mb I'm sure, though might be harder to source. A couple of extra I/O pins on the Xilinx shouldn't be too much of a bind to jumper, though would certainly involve more bug testing :)

Not sure as to the current state of the Suska core, though Wolfgang seems to think it's capable of running a good chunk of ST software. How accurate that is remains to be seen.

I'll get some parts ordered then and get back to you. :D

-Joel
520 STFM (Upgraded to 1mb)
520 STFM (Stock)
520 STFM (Stock)
1040 STE (Stock)
Falcon 030.. I wish!

User avatar
stimpy
Captain Atari
Captain Atari
Posts: 305
Joined: Mon Aug 22, 2005 2:47 pm
Location: Somerset, UK
Contact:

Re: FPGA 68000

Postby stimpy » Mon Feb 25, 2008 1:23 pm

Joel wrote:
Not sure as to the current state of the Suska core, though Wolfgang seems to think it's capable of running a good chunk of ST software. How accurate that is remains to be seen.


It's pretty accurate!
Netus-Bee,Repairs,Upgrades,EtherNEC,Eiffel

User avatar
alexh
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2595
Joined: Wed Oct 20, 2004 1:52 pm
Location: UK - Oxford
Contact:

Re: FPGA 68000

Postby alexh » Mon Feb 25, 2008 6:08 pm

stimpy wrote:It's pretty accurate!

You're saying this from experience? What FPGA platform are you using? Which tool-chain did you use?

Looking at the code there are some "horrible" bits that I am not 100% sure will synthesise (but it could just be the strange coding style). Might have a go tomorrow just a quick go with the Target being the MiniMig FPGA.

It will probably take too long (a few hours) to get real scripts in place and work out the DCM, RAMS and pin-listings etc.

User avatar
stimpy
Captain Atari
Captain Atari
Posts: 305
Joined: Mon Aug 22, 2005 2:47 pm
Location: Somerset, UK
Contact:

Re: FPGA 68000

Postby stimpy » Mon Feb 25, 2008 8:05 pm

I've been working on average 8 hours a day, 7 days a week since the start of the year on the code, reading and working it out, so I know it quite well now. I think it's quite clear, as good as it can get when keeping the components seperate like the original ST.

Enterpoint Student board, Xilinx ISE Webpack, 68SEC000, modified Eiffel.
Netus-Bee,Repairs,Upgrades,EtherNEC,Eiffel

User avatar
earx
Captain Atari
Captain Atari
Posts: 353
Joined: Wed Aug 27, 2003 7:09 am

Re: FPGA 68000

Postby earx » Tue Feb 26, 2008 12:34 pm

stimpy: does that mean you are actively involved in the suska project? or just shadow engineering it on your own? :)

User avatar
alexh
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2595
Joined: Wed Oct 20, 2004 1:52 pm
Location: UK - Oxford
Contact:

Re: FPGA 68000

Postby alexh » Tue Feb 26, 2008 1:47 pm

stimpy wrote:I've been working on average 8 hours a day, 7 days a week since the start of the year on the code

Don't you have to go to work or something? :-)

If you've been working on it all that time, you must have got something going by now? Lets have a few photo's of it up and running.

I don't think there is any floppy disk emulation included in the current Suska project files. I think it was intended to use real floppy disk drives. That will be the first thing to change once I get a MiniMig board. It should be fairly painless to link into the MiniMig PIC floppy disk emulator.

Where does Wolfgang (Author of Suska) hang out? It would be good to get him here (or us go there) to help forward the project.

User avatar
stimpy
Captain Atari
Captain Atari
Posts: 305
Joined: Mon Aug 22, 2005 2:47 pm
Location: Somerset, UK
Contact:

Re: FPGA 68000

Postby stimpy » Sat Mar 01, 2008 4:30 pm

alexh wrote:
stimpy wrote:I've been working on average 8 hours a day, 7 days a week since the start of the year on the code

Don't you have to go to work or something? :-)


Student :lol:

alexh wrote:If you've been working on it all that time, you must have got something going by now? Lets have a few photo's of it up and running.


http://youtube.com/watch?v=3z5JKzoiNXo

alexh wrote:I don't think there is any floppy disk emulation included in the current Suska project files. I think it was intended to use real floppy disk drives. That will be the first thing to change once I get a MiniMig board. It should be fairly painless to link into the MiniMig PIC floppy disk emulator.


The thought is in my head to ditch floppy drive at some point. There are countless ways of doing it, and I think most important is keeping the component count of memory storage devices to as little as possible.

alexh wrote:Where does Wolfgang (Author of Suska) hang out? It would be good to get him here (or us go there) to help forward the project.


Not sure, I think he is very busy though.
Netus-Bee,Repairs,Upgrades,EtherNEC,Eiffel

User avatar
unseenmenace
Atari God
Atari God
Posts: 1961
Joined: Tue Sep 21, 2004 9:33 pm
Location: Margate, Kent, UK
Contact:

Re: FPGA 68000

Postby unseenmenace » Sat Mar 01, 2008 4:55 pm

stimpy wrote:http://youtube.com/watch?v=3z5JKzoiNXo

Oooh 8)
UNSEEN MENACE
Several STFM's, 4MB STE, 2MB TT with 1.2GB Hard Drive and 14MB Falcon with 540MB Hard Drive,
Lynx 2 and Jaguar with JagCD
Member of GamebaseST and AtariLegend team
Check out my website at http://unseenmenace.110mb.com

User avatar
alexh
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2595
Joined: Wed Oct 20, 2004 1:52 pm
Location: UK - Oxford
Contact:

Re: FPGA 68000

Postby alexh » Sat Mar 01, 2008 10:54 pm

Interesting. Not running a demo or a game, but cool non the less.

I may have to get a board to help out.

User avatar
stimpy
Captain Atari
Captain Atari
Posts: 305
Joined: Mon Aug 22, 2005 2:47 pm
Location: Somerset, UK
Contact:

Re: FPGA 68000

Postby stimpy » Sat Mar 01, 2008 11:24 pm

That video is a bit old, had it running the RG hallucinations demo, with overscanning lower border removal 8)
Netus-Bee,Repairs,Upgrades,EtherNEC,Eiffel

User avatar
unseenmenace
Atari God
Atari God
Posts: 1961
Joined: Tue Sep 21, 2004 9:33 pm
Location: Margate, Kent, UK
Contact:

Re: FPGA 68000

Postby unseenmenace » Mon Mar 03, 2008 6:55 pm

Here is a little "artists impression" of what (in my view) an ST replacement should look like. Its not 100% to scale but close enough :) . All we need now is someone who works in plastics to make such a thing 8)
You do not have the required permissions to view the files attached to this post.
UNSEEN MENACE
Several STFM's, 4MB STE, 2MB TT with 1.2GB Hard Drive and 14MB Falcon with 540MB Hard Drive,
Lynx 2 and Jaguar with JagCD
Member of GamebaseST and AtariLegend team
Check out my website at http://unseenmenace.110mb.com

User avatar
PaulB
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2168
Joined: Tue Jun 11, 2002 10:56 pm
Location: You Kay

Re: FPGA 68000

Postby PaulB » Mon Mar 03, 2008 8:02 pm

So you want to do away with the floppy entirely?


Return to “FPGA Chat”

Who is online

Users browsing this forum: No registered users and 1 guest