I made many other attempts on usbSID project (see previous post), I even wrote to FTDI support people (who gladly answered to my questions) and it seems that the latency issues won't be easy to solve...

Anyway, I decided to try something else for the moment : building the Parallel Port SID 6581 Synthesizer Chip Interface.

I made a few changes, especially adding some buffers to isolate the parallel port and enforce the logic signals. Here is the result, on a breadboard...


You can see in the middle of all this mess the legendary MOS 6581 (click on the image to get the full-size picture). For audio output, I picked a ready-to-use board featuring an amplifier and a small loudspeaker. The audio amplification and output part needs some rework, as it doesn't sounds very good at the moment :)

Like many people, I like C64 music and the special sound of its SID component. So I looked at the Parasid (Parallel Port SID 6581 Synthesizer Chip Interface) project, as I own a laptop myself, so I won't be able to use HardSID boards, for instance.

Parasid's author is working on an USB interface instead of a parallel port interface, which sounds very nice, as many computers doesn't feature parallel ports (Macs, and newest PCs).

So I decided to give it a try, using the USB FIFO IC already used in many projects, and a VHDL implementation of a SID, to ease up the development process (no board to build/assemble).

I managed to put all that stuff together, and wrote a patch for VICE, and it worked... well, kinda.

Unfortunately, the system suffers from latency issues : although the overall speed of the USB link would be sufficient to meet the requirements, communication suffers from setup time issues. I don't know if it's due to the FIFO IC, or to USB capabilities (I must admit I don't know anything about USB).

I planned to show this project in the VieuMikro meeting which will occur in a few, but obviously, it won't be ready. Well, I need to learn more about USB, and try to find a solution...

VieuMikro 2006 meeting is coming soon! And this year's edition will feature a special expo about the Intellivision. So I thought it was the opportunity to work again on my IntvFPGA project, to enhance it. When I demonstrated it at the Infoticaires 2006 meeting, it was only able to run a few public domain ROMs...

I cleaned up my previous code, corrected some timing issues, and added the ability to load ROMs through USB instead of having them stored in the FPGA configuration EEPROM. And it works much better now : it is able to load many more ROMs now, including most commercial ones.

It should be a good tool to show special stuff at VieuMikro (if nobody brings an Intellicart, of course). Speaking about Intellicart, my project lacks many features of it, but well, it's still a good start. And above all, as you can see on the picture below, it is able to run the Spirit demo made by Arnauld Chevallier, the famous French Intellivision guru :)



You can download the full-size picture here