MiniMig with AGA

[xyzzy]

I like it! Keep up the good work / drinking

[xyzzy]

The NatAmi design is planning to extend AGA, I think if the MiniMig AGA core is extended then it should be designed to be register compatible at least.

[xyzzy]

The most obvious way to expand the AGA core is to add oodles of extra bandwidth to allow high-res AGA screenmodes and ultra fast blitter access without slowing down CPU accesses. This should be transparent to all well-behaved software. Games might need a compatability mode however.

[xyzzy]

I'd like to see what happens when a team of demo coders get their hands on one.

[xyzzy]

Isn't that just for continuity?

[xyzzy]

I'd rather have one with SVideo and composite out as well.

[xyzzy]

We could see all sorts of things emerge, an extended AGA chipset (more planes/resolutions/sprites), AGA but with no DMA contention, a built-in p96/cgfx compatible RTG graphics card and vga switcher or anything else we can squeeze in.

[xyzzy]

The Replay board is supposed to be a multi-purpose board, not just amiga specific. 256MB of onboard ram would be overkill for many applications.

If more ram is needed it can be added via the expansion connector, on a cpu board for example.

[xyzzy]

How simple was the UAEGFX picasso96 "driver"? Totally alien to a real driver?

The advantage of replicating the WinUAE hardware RTG card is that we have the source code to hand and know how its supposed to work.

[xyzzy]

I was thinking how the main board can communicate with the outside world. There's a debug serial port over which we could run PPP or SLIP, or we could use the ARM with its USB port to emulate a high-speed serial-over-usb link.

Secondly, i've been studying the schematics and I don't see any issues with plugging amiga mice into the joystick ports - the h/v pulse lines all go straight into the FPGA, and all three mouse buttons are accounted for.

However I think the ports will be only wired up to 3.3v according to the schematic.

Will this be a problem for autofire joysticks? Do they expect 5v for their electronics ?

[xyzzy]

Only sprite and bitplane DMA could use 32-bit fetches (64 with burst), everything else in AGA is still 16 bit, including the blitter and chip registers.

[xyzzy]

Yes. Although I believe the display DMA fetches one chunk of data from each bitplane in turn, ie 16/32 or 64 bits of data before fetching the same amount for the next bitplane.

[xyzzy]

Party time! \o/

[xyzzy]

Hopefully we'll see an Amstrad CPC (+) core too

[xyzzy]

There are lots of ways AGA can be improved. The most obvious one is eliminating the "SuperHiRes 8-bitplane" DMA slowdown, others include speeding up blitter operations. Hopefully 1280x512 would become totally useable.