I'm looking to build a couple of these. However, I don't understand quite a few things.
- What is the output voltage that an RGB monitor would expect from the R, G, and B lines?
- The R2R ladder, can it be simply replaced with a 8-bit DAC?
- I'm looking to using an adapter to cleanly solder the CPLD. All I'm finding is TQFP adapter PCB. But isn't the XC9536XL CPLD a VQFP? Are they compatible?
Bump!
I made a small adapterboard to solder SMD 0603 resistors (280 and 560 Ohm 1%) and also the 100nF cap and the 220 Ohm.
I made a few so if you want one let me know.
(http://s11.postimage.org/7plu0j3n3/N64_RGB_DAC_PCB.jpg) (http://postimage.org/image/7plu0j3n3/)
Here's a picture that explains what goes where, resistors are 560 kind straight out from the CPLD pins and also the three that connects to ground (at the end of each ladder). The other ones are 280 except the 220 Ohm for composite sync. The cap is marked as you can see.
(http://s15.postimage.org/gpw35tikn/RGB_DAC_cad.jpg) (http://postimage.org/image/gpw35tikn/)
If you want to make a board yourself let me know and I can send the files for Eagle CAD or the gerber files.
The reason I made my board was because Tim showed this on his homepage:
(http://members.optusnet.com.au/eviltim/n64rgb/10.jpg)
I thought it looked a bit dangerous, very artistic though. ;-)