Jamma FPGA devkit
- Thread starter lix
- Start date
Retroman839
Senior Member
Awesome work bro keep it up!!
Still working on it!
Being new to FPGA there's been a bit of a learning curve. I've been battling against bugs mainly down to timing constraints being needed in the logic.
Things would work absolutely fine one build, then on the next compile I would get erratic behaviour which was completely unrelated to what I would be working on. Turns out it's timing issues caused by the random planning of gates and the way they are routed.
I've finally got loading of program executables and graphics data working from a Fat32 formatted SD card. Still want to flesh up a bit of a workable system though before I publicly release a software project for the board, but I've now put up the EagleCAD board, schematic and BOM files for the prototype PCB online.
Had a couple of estimated quotes back for assembly and they weren't bad, but I still can't nail down a final price for retail just yet.
I can't offer support on the prototype PCB manufacturing files as although it's largely tested okay I still haven't had absolutely everything running at the same time. As it stands, it can at least operate as a testcard generator!
Thought I'de put them up so interested parties could have a look and a tinker with them though.
https://github.com/stevej0/goJAMMA
Steve.
Things would work absolutely fine one build, then on the next compile I would get erratic behaviour which was completely unrelated to what I would be working on. Turns out it's timing issues caused by the random planning of gates and the way they are routed.
I've finally got loading of program executables and graphics data working from a Fat32 formatted SD card. Still want to flesh up a bit of a workable system though before I publicly release a software project for the board, but I've now put up the EagleCAD board, schematic and BOM files for the prototype PCB online.
Had a couple of estimated quotes back for assembly and they weren't bad, but I still can't nail down a final price for retail just yet.
I can't offer support on the prototype PCB manufacturing files as although it's largely tested okay I still haven't had absolutely everything running at the same time. As it stands, it can at least operate as a testcard generator!
Thought I'de put them up so interested parties could have a look and a tinker with them though.
https://github.com/stevej0/goJAMMA
Steve.
lix said:Still working on it!Being new to FPGA there's been a bit of a learning curve. I've been battling against bugs mainly down to timing constraints being needed in the logic.
Things would work absolutely fine one build, then on the next compile I would get erratic behaviour which was completely unrelated to what I would be working on. Turns out it's timing issues caused by the random planning of gates and the way they are routed.
I've finally got loading of program executables and graphics data working from a Fat32 formatted SD card. Still want to flesh up a bit of a workable system though before I publicly release a software project for the board, but I've now put up the EagleCAD board, schematic and BOM files for the prototype PCB online.
Had a couple of estimated quotes back for assembly and they weren't bad, but I still can't nail down a final price for retail just yet.
I can't offer support on the prototype PCB manufacturing files as although it's largely tested okay I still haven't had absolutely everything running at the same time. As it stands, it can at least operate as a testcard generator!
Thought I'de put them up so interested parties could have a look and a tinker with them though.
https://github.com/stevej0/goJAMMA
Steve.
Thank you for sharing your work!
Bishop said:
It kind of stalled for a bit while I had a bunch of other stuff to do, primarily working on opening an arcade and getting a load of machines ready for that, but I did do a bit of work recently on making my own logic core and coding a racing game demo to show it running.
I discovered a couple of minor issues with the last prototype boards I made about a year ago and I've just not had the time or cash to do a new revision, although I might be able to do something about that in the next month. I'de been torn between using a 8mbit SRAM chip for main memory or using an SDRAM similar to what the MiSTer FPGA project uses so I could port more cores, but I like the simplicity of the SRAM interface.
Have done some other projects with the board though. I ported the Atari Pong verilog core to it and that works great. Made a nice testcard generator, and also had a go at making my own Sinclair Spectrum core, so now I can play spectrum games in my jamma cabs.
I'm coding the racing demo in C which is running on a soft 6502 at 16Mhz, and I made blitter logic that can do 64 sprites of 32x32 pixels per frame as well as update the background layer, I was quite pleased with that. I also added a couple of other features such as a bitmap cache to speed up blitting if you are rendering the same object multiple times, and it can also do polygon filling. I'm pretty keen to get something in 3D running someday, I've put in a hardware multiply and divider as well for some maths.
So progress is happening, just a bit erratic and slow at the moment sorry.
