MiniMig Development

[bloodline]

Ok, Where do we stand with the MiniMig development?

This is really three questions:

a) The softcore development was being hacked by several on this board... what sort of state are we at? New features? Big fixes?

b) I notice the Spare I/O header, any thoughts as to what the future may hold... to me it looks like it begging to be programmed as a high speed serial interface...

c) I haven't looked but are we able to source and even interface an EC020 in place of the 68k?

[alexh]

bloodline wrote:
are we able to source and even interface an EC020 in place of the 68k?

The MiniMig's FPGA has 3.3v I/O pins. The only 3.3v 68k is the MC68SEC000.

FPGA outputs doesnt matter, 3.3v is well within 2.0v - 5v TTL logic levels any 68k expects.

FPGA inputs must have an in-series resistor because the XC3S400-4PQ208C does not have 5v tolerant I/O.

There might be a problem for bidirectional I/O (are there any?)

It would be cool to see if anyone can do this, a MiniMig with a 100MHz 68060 would be cool.

Anyway you look at it, it involves a new PCB. But I guess you gotta start somewhere.

[alexh]

The other big problem with MiniMig is RAM. 2Mbytes (of which 512Kbytes is used for Kickstart) just isnt enough. Ideally we'd want 2+4 Mbytes (Plus kickstart) so two banks of 4Mbytes would seem a good idea.

Do they make larger SRAM chips? Are they similar pinouts? Do they cost the earth?

Would it just be two more I/O pins for an additional address line going to both chips to quadrouple the SRAM size?

Are there enough unused I/O pins on the FPGA to use larger SRAM chips?

This (in theory) sounds like a quick mod that could be made to existing MiniMig PCB's to greatly improve the overall usability of MiniMig.

Out of curiosity, how does the PIC access the SRAM (to load the Kickstart from MMC card)? Does it use a special path through the FPGA programmed in during configuration?

[alexh]

I would also like to see hard disk emulation on MiniMig. I dont know if this is practical given the current PCB & PIC but it would be good to know if the only thing that needs doing is a new PIC code and the FPGA mods

[bloodline]

Looking around the Freescale website, I can't find the 3.3V 68k... all the 680x0s are 5v... though it does make reference to a 3.3v model being available... Looking at the prices though... it's prohibitive to use anything but the 68000 really... The next cheapest is the MC68EC020AA16 at $12 per 1000... -Edit- What the McFCUK is "Floor Life"?

I totally agree about the RAM... I expect there is sufficient IO already there to address more RAM... but the price of the chips again will probably push the cost of the design to something horrible.

[bloodline]

alexh wrote:
I would also like to see hard disk emulation on MiniMig. I dont know if this is practical given the current PCB & PIC but it would be good to know if the only thing that needs doing is a new PIC code and the FPGA mods

I would be surprised if it wasn't easy to put a simple ATA emulation to directly access the MMC.

These are all questions for the FPGA hackers here!

[Crom00]

Hardfile support and software 68k in fpga are paramount. I actually have a Mini-MIG since Oct and let me tell you. The insert floppy repetition really kills the replay value.

I honestly think this is why  16 bitconsoles were so popular in t he us. NO LOAD TIMES.

For this to work in a commercial sense (or even non Amiga Geek sense) it really needs to have HARDFILE support so that we can start making Mini-MIG workbench distributions.

[warpdesign]

For this to work in a commercial sense (or even non Amiga Geek sense) it really needs to have HARDFILE support so that we can start making Mini-MIG workbench distributions.

Non-geeks need a full-working solution anyway, full working as in "plug and play"... If you have to download workbench + roms,... it is already an obstacle for non-amiga fans/geeks...

And right now kickstart & workbench unfortunately isn't freely distributable, so unless you make some agreement with Amiga Inc. to include kickstart/workbench with it, it won't pass the geek market...

[alexh]

bloodline wrote:
Looking around the Freescale website, I can't find the 3.3V 68k... all the 680x0s are 5v... though it does make reference to a 3.3v model being available...

Eh? It's on the main page in B&W!

Freescale wrote:
The MC68SEC000 version provides a static, low power implementation consuming only 15.0mA in normal 3.3V operation

[bloodline]

alexh wrote:

bloodline wrote:
Looking around the Freescale website, I can't find the 3.3V 68k... all the 680x0s are 5v... though it does make reference to a 3.3v model being available...

Eh? It's on the main page in B&W!

Freescale wrote:
The MC68SEC000 version provides a static, low power implementation consuming only 15.0mA in normal 3.3V operation

Yeah, that's the one ref I found... the actual product charts, with the price and specs, all show 5V...  :-?

[alexh]

Crom00 wrote:
software 68k in fpga [is] paramount.

Why? More RAM is surely more important!

[alexh]

bloodline wrote:
the actual product charts, with the price and specs, all show 5V...  :-?

It says on the product brief 3.3v or 5v operation

It's interesting you should point this out, cos it made me look at the 68060 again and voila 3.3v or 5v I/O capability

Very interesting. It looks like an MC68060RC50 running at 100MHz could be the heart of a next generation MegaMig(TM).

[bloodline]

alexh wrote:

bloodline wrote:
the actual product charts, with the price and specs, all show 5V...  :-?

It says on the product brief 3.3v or 5v operation

Ok, yeah, I can see the refs... but the Product lists are not forthcoming:

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MC68000&tab=Buy_Parametric_Tab

It's interesting you should point this out, cos it made me look at the 68060 again and voila 3.3v or 5v I/O capability

Very interesting. It looks like an MC68060RC50 running at 100MHz could be the heart of a next generation MegaMig(TM).

Well yeah!!! That would be cool! But the cost is prohibitive since any Amiga product really needs to be around the £100 mark (ie not too much more than second hand real hardware prices) to make any sense...

[CodePoet]

@ alexh

There might be a problem for bidirectional I/O (are there any?)

I use ADG3304BRU & ADG3308BRU bidrectional translator ICs for alot of my work, they work really well - you'd probably need alot of them though, but it is doable  :-D

[Crom00]

No hardware Motorola CPU means lower cost. Using DRAM would lower cost also allowing more ram. I asked Dennis about this.

Yes to make it truly "plug&Play" would require a serious licensing deal. The whole floppy disk loader thing is a pain. Something line those CD32 game compilations would be cool.