thursday, 4 march 2010

posted at 09:51

Nothing big to report, just work plodding along, so here's an update in pictures.

Here's the fully assembled N64 RGB DAC board:

It's not currently working though, so some debugging is required. When I hook it up I get no picture, and occassionally it seems to short out the whole console. I haven't really had time to diagnose it properly yet. I'm mostly waiting to figure out a systematic approach, since its all a bit confusing right now.

My other project is the USB-to-N64 controller bridge. I've written a lot of AVR assembly for this so far but haven't done any actual hardware work. Its coming very soon though, so I very carefully removed the cable from one of my controllers (so I have the option of putting it back together later) and added some pins to the end so I can connect up a breadboard:

This is my first outing with shrinkwrap tube and it was a breeze. My wife has a hot air gun that she uses for her craft work, mostly with embossing inks, so I borrowed it and it worked brilliantly. I was surprised at how much physical strength it actually gives.

This is the insides of my N64:

The large ribbon is the digital signal tap for the RGB DAC, soldered to the inputs on the existing composite DAC chip (easier to solder to that chip than to the much narrower output pins on the video chip. The brown/black pair in the left is the 3.3v power feed for the RGB DAC. Over there on the right under everything is a DE9 D-sub connector with lines for the outputs from the RGB DAC (the narrower ribbon), audio from under the multi-out (the purple/gray/white ribbon) and a 5v line that's needed for some SCART signalling (the fat red wire). Right now its actually hooked to a 3.3v line under the board because I was testing something. Soon I'll hook it instead to the 5V regulator you see just to the right of the composite DAC.

Finally, some recent ebay loot:

Clockwise from top left: a pack of 78L33 3.3v voltage regulators; a sheet of 6 74HC374 8-bit latches and 4 74HC04 inverters; an anti-static pack containing two ATmega88 microcontrollers; a giant roll of 560-ohm 1% resistors (190 left on the roll); a tube of 74HC04 inverters; and a pack of 10n ceramic capacitors (which I use for IC bypass caps).

As I've mentioned before, ebay is an incredible source of cheap parts. There's less than $30 of parts in this picture, and that's not everything I've bought recently. I love getting home every second day and there's a little parcel waiting for me!