minimig 4000

[AeroMan]

Hi to all,

    Wow, this thread is hot... seems to be that everybody have a small poject on the Amiga based on Minimig.
    I'm planning some stuff also, but as my time is getting very short, I don't want to make it public, as it may not see the light of the day (3 years old twin daughters and a classic car to restore fills my weekends :-D )
    Let me share some of my opinions. Then you can throw me some rocks :-D. I really believe that if there is a future for the Amiga it is in our hands, as the "big companies" had proven to be such a disaster. There are a lot of other folks doing compatibles around the world, and Minimig is a great start.
    I think if AGA compatibility is the target, we should have that in mind when doing any board. The hardware should be capable of supporting it, and we can grow the software slowly from OCS to ECS and then AGA without doing new boards. This keeps costs acceptable for us hobbists.
    The 68060 is an expensive guy. Coldfire is cheaper, but a litle bit incompatible. I would go to PPC, as OS4 needs it, and it is cheaper than the 060, but I believe the best place to start is to seek A1200 compatibility, so use a 020 or a 030 as a plug in daghterboard. It helps to use processor development kits also.
    Most software will run with AGA and 020. When we get A1200 compatibility, a PPC is the best choice to speed it up.
    Virtex 4 is also expensive. You can get a cheaper set up with a MPC5200 and a Spartan3, and the MPC already has SDRAM/DDR controllers, Ethernet, USB and some stuff more.
    I've talked with some friends who work with FPGAs, and they told me VHDL would fit best for this kind of project, althrough Verilog is easier to learn. I'm trying to learn Verilog first anyway.
    Now two quick questions to the people who are playing with Minimig already: How many gates are we using from the Spartan ? I would like to know how big we could expect an AGA version to be...
    The second one: wouldn't it be cheaper to use two or three smaller FPGAs for an AGA Minimig than upgrade to a bigger FPGA? The cost of those chips seems to grow exponentially.

[AeroMan]

alexh wrote:
I dont know who you're mates are but they are either poor engineers or they make stuff up they dont know!

VHDL and Verilog are just languages, you can write exactly the same thing in both languages.

I'm not stating that we should ignore what was done in Verilog and try to rewrite everything in VHDL. It was just one comment from them I would like to share.

Actually, one of them is PHD... What they told me in that discussion is that there are some stuff that you can implement in VHDL easier than in Verilog, but it is more difficult to learn. I'm starting to learn those languages right now, so I don't have enough knowledge to say if it is true or not, but it sounds reasonable to me, as Assembly and C are also languages and althrough C is very powerful, there are things that can't be done using it. You can do everything in Assembly, but it is way more difficult.

alexh wrote:
Impossible metric to measure, even if you knew the current size of MiniMig

Yes, It can give me a north to go. With the 60% number that AJCopland said below, I can tell the hardware needs prevision for a second FPGA or a bigger one, but it may fit in the current chip. Why? Because Paula and the CIAs are the same, blitter and copper have little differences, and the big work will be on Lisa and the memory fetch part of Alice. If the number was 30%, for example, I would say 99% of chance that if there are enough free IOs, we can use the same chip.

alexh wrote:
However IMHO form-factor is a bit selling point of MiniMig. In fact to me, it's the only selling point.

I agree with you, if we consider the Mini side fo Minimig. But if we are heading to a new Amiga hardware, we will need more area for stuff. The A1200 and A500 have perfect sizes, but a PC sized board would be nice, as we could fit it inside cheap PC cases.