(warning, long post. For your question about using Gameduino as a GPU for a hobby machine, I think it looks good, and straightforward - see
the hardware page.)
Should I get the Gameduino with the GPL license
Hmm, your earlier message tells us that some of the
samples have some GPL content:
Some of the samples have used GPL artwork, so they are all GPL.
but I see the
kickstarter page (where you can more or less buy one for $53) says that all the code is GPL. I suppose that would mean the FORTH runtime, the game library, and the samples. (Edit: James clarified that there is no runtime. So, if you use the game library, you're in GPL territory, similarly if you mutate one of the samples for your project. But if you work it as a graphics adaptor there's no GPL aspect.)
My conclusion would still be that this is fine for all purposes: if you had secret sauce you'd need to put it in configuration files which you license separately from your game source files.
Getting any kind of FPGA board seems like a good idea to me, if you think you'll put in the effort to learn how to drive it. Certainly easier than making your own board: that can come later. You'll have a choice of schematics, verilog or VHDL, and you can mix and match, and there's quite a lot of examples out there to make use of and learn from.
As far as I can see, the
Gameduino hardware includes the FPGA and has a JTAG port so you can re-program it - all you'd need is a cable, and confidence that you can re-load the original design if you need to.
Working with the Gameduino in the intended way, as a graphics coprocessor, means writing values to its memory over the SPI bus. You don't have to work in FORTH on the (very interesting looking, minimal, 16-bit)
J1 CPU and indeed you don't even have to read/write values directly if you use the GD games dev library on an Arduino.
So, it's an Arduino addon, it's an FPGA dev board, it's a graphics subsystem and it's a FORTH CPU playground. And because it's open source, you're invited to
make your own.
If you want to test yourself out on verilog or VHDL you can download the free 'ISE webpack' software from Xilinx and go through an exercise of designing something, and simulating it. (Or, if you're happy with command line working, use
Icarus verilog which is open source and a great deal smaller.)
