Minimig PCB run - interest thread

[billt]

Hows about making it easy to fit into a Mini-ITX case? I'm not saying easy as in what you'd need to do to mount an Efika in a Mini-ITX as I don't want to be drilling new holes and crap like that, but something with screw holes in the correct places on the Minimig PCB, connectors at the back, add standard power supply connector if needed, etc. to minimize our own personal case fabrication requirements. I'd also put the MMC slot on the back panel for easy access instead of tearing apart the case to swap if you ever need/want to.

[billt]

For everyone wanting to keep 12x12cm size, if that is chosen as the thing to do, at least go with Nano-ITX which I believe is that size. I think there are some Nano-ITX to Mini-ITX coversion kits to fit standard Nano boards into standard Mini cases, and there are probably Nano-ITX cases by now. Whatever is done, at least pick some standard to do it in.

[billt]

Another thought if a new motherboard is made. If there's enough available pins on the FPGA (perhaps pick a different FPGA package to add more pins), put on some additional things that may not be in the current MiniMig design but which could be added with time to the Verilog design. An IDE port, ethernet, and perhaps PCI slot as examples. There's a ton of things on opencores which might be combined into MiniMig. Maybe a larger motherboard will be made someday which could have Zorro slots and video slots as well in addition to PCI and maybe PCI-Express with a PCI-?PCI-Express bridge chip), sortof like early Boxer ideas were.

[billt]

Been there, done that. Heat and pressure often smudge the traces on the qfp tracks, thin tracks often get lifted off the board when removing the wet paper, etc. Applying heat and pressure uniformly is difficult, the larger the board, the higher the incidence of over pressure and heat on some spots, under pressure and heat on others. Some traces smudge, others don't stick. Getting the top and bottom layer aligned right will make you go postal.

What about photosensitive bare boards and printing to transparencies for exposure?

But yes, I'd agree that having it made by a real manufacturer would give best results.

[billt]

Would it be possible to add more than one CPU on future revisions?
What about an DSP, like on the Delphina cards?

The neat thing with FPGAs is that you can do just about anything you want, so long as there is enough room in them for your logic design and enough pins to interact with the outside world. You'd need to add some control logic to the FPGA allowing it the capability to arbitrate and talk to the DSP properly, and assign some FPGA pins to wire up to the DSP on the PCB. Perhaps some of that could be shared with the 68000 bus, perhaps not. It sounds like there's cocnern that the largest pincount QFP style package which is easier to work with does not have enough pins for an IDE port and other things in addition to Dennis's design features. Larger pincount versions of the FPGA exist, as do larger logic capacity FPGAs. Unfortunately the larger pincounts come in BGA, which is much harder to work with, and it's expensive to send out for assembly by a proffessional company. And larger logic capacity FPGAs are just freakin expensive chips. You of course could look for some balance in there, but you'd at least need more pins and thus BGA version to add much more control signals or address/data bussing, even if the additional logic design fits into the same FPGA.