PCB Prototype of the SID Filter / Sound Board

Well, after working on it for 2 months, I have finished design of the hardware and have made a PCB, then stuffed it. I am missing 4 or 5 parts though so I haven’t fired it up just yet. First the pictures:

Now that those are out of the way, what the hell am I looking at? Well, it’s evolved into alot more than just a simple SID emulator. It’s turned into a small portable hand held battalion of FPGA and audio goodness.

On board are a Cylcone 3C25, 16Mbytes of RAM, a PIC micro, USB, SD card, dual 1/4″ jacks for audio out, a 1/8″ stereo headphone jack (not on the board yet), MIDI in, and a bunch of debug/programming connectors and the 20 pin display connector. There’s dual analog SID filters, 4 24 bit audio DACs, digital volume controls and other analog goodies.

The plans for this beast are simple: a programmable MIDI box that lets you “play” nearly any kind of classic videogame or computer sound you wish. The second function is a full inclusive chiptune playing “engine” that reads tunes off the SD card and then plays them.

There’s a 132*32 pixel LCD with backlight that connects up to the 20 pin connector, and the 4 mounting holes at the top receive it. I do not have it mounted just yet since I was busy soldering it all up. I need get some hardware to mount it at the exact right height for my box, too. The box has a holder for 4 AA cells, which will be nicads or NiMh more likely, and will power the works.

The USB and SD card will act together as a standard windows/linux/etc. mass storage device to allow you to plug it in and drag/drop tunes to/from it. The USB will also provide recharging power to charge the batteries up. A DC power jack will be provided too for running it at a gig if you don’t want to use batteries.

Well, that’s about it for now. Here’s a sample of what the current hardware sounded like before I made the PCB. It’s about as good as can be done using standard parts. The filter’s offset and span can be tweaked in software now though, so I can change the response greatly.

current version 20 filter test.

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