Gameboy Development Forum

Discussion about software development for the old-school Gameboys, ranging from the "Gray brick" to Gameboy Color
(Launched in 2008)

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#1 2008-03-29 22:28:30

nitro2k01
Administrator
Registered: 2008-02-22
Posts: 245

FPGAboy project started

Edit, there was already a project called FPGABoy by Costis Sideris. His page is long gone, but here's a mirror on archive.org: http://web.archive.org/web/200602070330 … gaboy.com/

Joshua, a member of the #gbdev IRC channel, is designing a hardware based Gameboy clone in Verilog. The project is has only just begun, and this is what I've been able to conclude from what he has said in the IRC channel:
* So far it supports only a couple of opcodes, a few loads and pops/pushes. (Enough to do LD HL, 0100h / LD SP, HL / POP BC / LD A, 12h / LD H, A / LD L, 34h / LD (HL), B / HALT)
* It's running on a NEXYS-2
* The plan is to keep the hardware bus clock cycle accurate with the original hardware. (A wise choice IMO, if you're striving for compatibility)

Here's a screenshot of a simulation of the timing (Or the whole circuit?)
http://gameboygenius.8bitcollective.com/images/yay-insns.png


Blog: Gameboy Genius
"A journey of a thousand miles begins with one small step"
Old Chinese Proverb

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#2 2008-04-06 16:56:55

Shiny
Member
Registered: 2008-03-17
Posts: 21

Re: FPGAboy project started

I'm interested in knowing what exactly this is. Is he creating a clone of the GB-Z80 by describing its structure in Verilog? If so, that's really neat and all, but what exactly is the advantage of doing so?

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#3 2008-04-06 22:25:24

nitro2k01
Administrator
Registered: 2008-02-22
Posts: 245

Re: FPGAboy project started

First and foremost I think he does it because it's a geeky project, but also a good tutorial in how FPGA programming works. Secondly if he manages to create a somewhat working clone, it would be easy to expand the functionality, ie add extra I/O, perhaps in-hardware MIDI I/O (My own little wet dream wink ) or advanced debug features like single stepping and conditional breakpoints on reads writes. It's also possible, although a bit more complicated, to add VGA output. And all this is in a package which is (Potentially) 100& compatible with existing games.


Blog: Gameboy Genius
"A journey of a thousand miles begins with one small step"
Old Chinese Proverb

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#4 2008-04-06 23:03:50

Shiny
Member
Registered: 2008-03-17
Posts: 21

Re: FPGAboy project started

nitro2k01 wrote:

First and foremost I think he does it because it's a geeky project, but also a good tutorial in how FPGA programming works. Secondly if he manages to create a somewhat working clone, it would be easy to expand the functionality, ie add extra I/O, perhaps in-hardware MIDI I/O (My own little wet dream ;) ) or advanced debug features like single stepping and conditional breakpoints on reads writes. It's also possible, although a bit more complicated, to add VGA output. And all this is in a package which is (Potentially) 100& compatible with existing games.

Ooh (: well that's really nice. Being able to properly debug in a truly accurate environment would be great. I don't know if I'd go for adding semi-unrelated extensions such as new I/O methods, but VGA out would be awesome (; (it's basically just a replacement for the screen so there's nothing wrong with that). I'm afraid that adding too many things would make it less of a Gameboy and more of a monstrosity in Gameboy casing ;P

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#5 2008-04-09 00:58:03

www.BoumPower.ch
Member
Registered: 2008-04-04
Posts: 20
Website

Re: FPGAboy project started

nitro2k01 wrote:

... it would be easy to expand the functionality, ie add extra I/O, perhaps in-hardware MIDI I/O (My own little wet dream wink ) or advanced debug features like single stepping and conditional breakpoints on reads writes. It's also possible, although a bit more complicated, to add VGA output. And all this is in a package which is (Potentially) 100% compatible with existing games.

I think that MIDI I/O willl be possible with our GB-PIC cartridge.... Microchip PIC16F877 has many hardware feature and is easy to program (ASM, C, Pascal, Basic, FlowCode....).
PIC16F877 running at 20 MHz without dependency of GB is much more powerfull than a FPGA cool

Last edited by www.BoumPower.ch (2008-04-09 00:58:42)

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#6 2008-04-13 15:54:27

Lamarre
New member
Registered: 2008-04-12
Posts: 4

Re: FPGAboy project started

I know there are similare projects (not with GameBoys of course but still) using the PICs from Microship...
the midiboxes at http://ucapps.de/.

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