TG68 - The Open Source Minimig CPU into the FPGA

[AJCopland]

Well done! Very good of you and in keeping with the spirit to open source it too :-)

Andy

[AJCopland]

freqmax wrote:
13 USD for another chip is a bit. Esp considering the FPGA is 25 USD..

Its not that much if it's replacing the PIC that costs £5.04 with a part that costs £6.80 (prices from Digikey uk).

Ok that does selectively ignore any additional components required for ethernet like the connection block etc.

Andy

[AJCopland]

downix wrote:
One thing I was pondering was in rolling this into a spare FPGA I have, and pairing it next to an original 60000, to duplicate instructions and see what differences there are.  Just need to find a minimalistic motherboard design for the 68k, like the old Altair, so I can directly manipulate them.

Didn't see this before.

Have you tried doing this?

Andy

[AJCopland]

ChaosLord wrote:
Why Z80 instead of 6502?

Why not an open source one from opencores.org or some other? Probably familiarity and competance at using it :-D It hardly matters as long as the chip is capable of whatever its being asked to do which doesn't sound like a lot.

On the plus side, the MegaDrive (Genesis for the US) used a Z80 so it's nice to know that already a 68k + Z80 + OCS can fit into the single FPGA!

Andy

[AJCopland]

I have a Sun-3/60 if anyone wanted actual hardware to compare an emulation against. It needs some love as it was pulled from a skip :lol: but there's nothing thats seems irreperably damaged.

Andy

[AJCopland]

Thanks Dennis & TobiFlex. Although I'm building Dennis' v1.1 MiniMig all of thise softcore cpu development is still extremely interesting and cool :-) Downloading them now and I've downlaod the core from opencores.org!

Andy

[AJCopland]

MiniMorph wrote:
I have just ordered 5 Altera DE1 boards from Taiwan.

I will sell a couple of them on in the UK if there is interest. I could sell them privately or on Ebay.

I could probably do the mouse keyboard mod on the boards and I will see if I can get some y cables as well. I will need then anyway.

Good news for my boot loader too. My development boards for that arrived today. I can actually run some code now !

Good to hear that your project is coming along, will you be sharing the re-design as you go or just at the end once you've worked all of the kinks out? I'm just getting to grips with gEDA (never used schematic software before) and trying to get everything setup correctly with the minimig sym files etc then trying things out in baby steps.

On a side note, damn this stuff is complicated when you're newbie, does anyone know of any good introductory guides!?! I've got it mostly installed and setup on Ubuntu, got the custom sym files from Dennis' site loading in ok and seemt o have teh schemtic loading with all of the components but an actual guide to using gEDAs gschema tool would be nice.

Andy

[AJCopland]

downix wrote:
I've been having an issue getting gEDA to read the gerber files myself.

I haven't got that far yet :-D might try that tonight since I seem to be too ill for going out and partying like Plan A had me doing :-(

Once I've had a go I'll report back. Will be happy if i can just get it to load up the schematic and all the syms correctly etc allowing me to edit things. My reasoning is that if I get each prior stage in the process to work then each subsequent one _should_ just fall into place.

I'm optimistic by nature like that :lol:

Andy

[AJCopland]

@freqmax
Thanks mate!

[AJCopland]

I think you can use whatever kit you like as long as you can recompile the VHDL/verilog to fit within the fpga that it uses AND use the ports that it has for input etc.

Honestly though thats just a guess

Andy

EDIT: ah I see that TobiFlex has already replied about it :-D