This is the second GBAPII++ Amiga graphics card I have built. I finished the last bit of the build two weeks ago. Today I tested it in my Denise Amiga clone and could confirm that it was working fine. If you are interesting in building one yourself, check out more information about the graphics card here. There are some details about the background of the card there too.
Hardware specs
The GBAPII++ is a Zorro 2 based Amiga graphics card based around the Cirrus Logic GD5434 chip. It has 2 MB memory and is a relatively affordable Amiga graphics card. Occasionally you see users referring to the card as an open Picasso 2 card as you can order empty PCBs yourself and build it. But if you know Amiga hardware well this card is based on another chip. The similarities are close though, both cards has only 2 MB and is probably likewise in performance as they are both Zorro 2.
The VGA adapter plate has both output and input so its possible to run scandoubler output through one VGA output, very handy and a must have these days IMHO. I use mine with a Indivision MK3 and it works perfectly out of box. Or run it with the Multivision-AGA scandoubler.
It is possible to use the card on an Amiga 500 by soldering an 86 pin 2.54mm edge card slot to the side of the card, thats probably why the graphics card goes by the name A500-GraKa.
Components
If you are thinking about building one I suggest you go looking for a GD5434 chip first. These chips are not impossible to find but can be pricey. I have paid between 20 to 40 euro each for Cirrus Logic GD5434 chips (currently have built four cards based on this chip). Finding an old VGA card and desoldering a chip with hot air is also a possibility.
The memory used is the same type of memory that is used in an Amiga 1200 1.4d revision. The typical SOJ40 2MB memory chips in the quantity of 4 chips.
I had difficulty finding the correct voltage crystal but eventually found the right one on AliExpress (and it worked too).
Building the graphics card
For some reason I thought building this card was incredibly confusing. I think the main reason is that I somehow got the build instructions for a previous revision of the A500GraKa card, once I got the correct file everything worked out fine! IIRC there are some solder pads marked as ferrite beads that should take resistors (or it was the other way). To find out what components go where one can look into the designer files, also study the BOM.
Performance
I have not tested performance yet and will probably never do, but make no mistake, this is no competition for a ZZ9000 graphics card. It is a fine card to use on a 030 based Amiga with a Zorro 2 bus as long as one do not go crazy on the amount of colors or resolution used. It is much better than using hires laced. I stick to 800×600 in 8 colors and it works fine.
Conclusion
Many thanks for the creators of this card and previous cards it is based on. I think this card is a no brainer, just get one if you have an empty Zorro slot and no graphics card. I will list the good things first and negative later, these are strictly my personal opinions.
Positive
- Half size card
- Has a hole cut out for your finger so you can remove it easely
- Autoswitch between scandoubler/VGA
- Open card, PCBs can be ordered by yourself. There is also commercial version of it
- There is a thread on a1k.org where you can ask questions about the card
- Supported in P96 (so you can install the card with the P96 installer)
Negative
- Somewhat confusing build instructions
- Only has 2 MB
- Is a Zorro 2 card so its slow (but still perfectly fine for lower resolutions/fewer colors)
