[awfgylbcxhrey]

I have a basic question: what exactly is it?

As a former Amiga user, I'm familiar with the Amiga's graphics co-processor(s). I actually forget now how many, I remember Copper and Blitter, but don't recall if those were chips, or functions on a single chip.

So, is this a sort of video adapter that converts the native Amiga video output to HDMI compatible signals, or is it full graphics card that brings Amiga graphics (32/64/4096 color, with acceleration) to modern output resolutions?

[mntmn]

It is a graphics card in the sense of the "ReTargetable Graphics" (RTG) system. I ship drivers for the Picasso96 API (which also emulates the competing CyberGraphX API). All OS friendly Workbench/Intuition GUIs can then be used on a high resolution (up to 1280x720@60hz, 1920x1080@30hz) and color depths of 8 (Palette), 16 or 32 bit. A bunch of open source games like Doom, Abuse, ScummVM have been ported as system friendly applications, too, so these run fine. Old games that bang the hardware still go through the custom chipset of the Amiga and are output through the 15khz RGB connector, not via my card. But I'm currently working on an expansion that scan-doubles and upscales the classic video output, too.

(Edit:) On the hardware side, I implemented the Zorro bus protocol in the FPGA (in Verilog) and hooked it up to a SDRAM controller/arbitrator and DVI/HDMI encoder. There is also a simple blitter in the code.

[jagger11]

Are you maybe thinking about adding more things on this one card? Ethernet, USB, memory (e.g. 1GB by default)...

Maybe even emulation of a faster CPU in FPGA (a'la the Vampire for A600).. though, it'd probably use the CPU slot instead of Z2/Z3.

Also, is it possible to hijack the function of the OCS/ECS/AGA directly via the Zorro slots (proxying the native output gfx output, e.g. with games), or maybe it'd require some kind of hardware bridge between the gfx chipset and your card?

[awfgylbcxhrey]

Thanks for the comprehensive answer!

[snarfy]

Agnus, Denise, and Paula.

https://en.wikipedia.org/wiki/Original_Chip_Set

[digi_owl]

Then later on there was the Enhanced Chip Set and the Advanced Graphics Architecture.

On that note, i think the A500 my parents got me back in the day were a oddity. I distinctly recall it having 1MB chip ram, suggesting it had the ECS inside. But it shipped with Workbench 1.x rather than 2.x.

[bartread]

That wasn't an oddity. It would have shipped with Workbench 1.3. I had one just like it with the Fatter Angus chip that could address up to 1MB of chip RAM, although you could still configure it as 512K chip and 512K fast, which is what I did.

I can't remember whether you did the 1MB chip config with a dip switch or by cutting a track on the motherboard - I think it may have been the latter, which is probably why I didn't do it.

[vardump]

I had a weird Amiga 500. It had late OCS chipset, but on hardware level its Denise could display bitplanes from slow RAM (512 kB RAM expansion)! Unfortunately I never tested blitter, copper lists, sample playback etc. from this memory range, so no idea whether those worked as well. Of course all is DMA access, so my guess is they would have.

RAM was mapped at 0x80000-0x100000 from chipset point of view. CPU saw same data at 0xc00000-0xc80000.

[snarfy]

Yep, I had the 500 too. They called the updated chip Fat Agnus.

[ZenoArrow]

Sounds like it could've been an A500+.

http://www.bigbookofamigahardware.com/bboah/product.aspx?id=...

[rasz_pl]

Amiga shipped with planar graphic modes, this card supplies chunky modes. Planar was great for ~10MHz CPU when moving 1-2 color images on the screen, but totally failed when technology moved on to 8-16bit color depth.

You could even argue Doom killed Amiga as a gaming machine.

[technomalogical]

Indeed, it has been argued. A great YouTube look at Doom's impact on the Amiga can be found here: https://www.youtube.com/watch?v=Tv6aJRGpz_A