I finally decided how I want to make the NGT30. After some first experiences with reflow soldering SMD, I have learned my limits.
Unfortunately, using FPGAs is unrealistic. It will take too long to come up with the VHDL, the chips are too expensive, and I will end up breaking half my boards due to soldering issues.
Fortunately, I have the propeller chip in SMD form, which I can solder!
I already have made a prototype board design in KiCad:
I know I can both build and program this.
The new design has numerous improvements over the NGT20. Now, RX/TX pins can be selected between a few different Arduino pins, thus increasing compatibility. There is now a reset button for the arduino too, to make it easier to reach the Arduino reset. I also added a PS/2 keyboard port, so now I don't have to keep cutting up keyboard cables :P. The board is also smaller and cheaper as a bonus.
I will be ordering this board *soon*. I plan to add I2C support to speed up the connection, but I have reason to believe that the MCUs are the bottleneck for the NGT20, so we will see how much that helps. Alternatively, the arduino would be able to use the hardware serial for the NGT20, parhaps allowing 1 Mbit/s connection to the NGT30.
We will see how this goes in maybe a month XD
Oh yea, what color should the board be?