Hi Cuno,
I'm going to expand on what Bertrand wrote a bit and take your questions one by one
If I understand correctly, your touch display has its own microcontroller, between the display and the Netduino Go. Is the "SPI up to 40 MHz" between display and your microcontroller?
That's correct: the display has its own STM32F2, servicing commands from the application running on the GO! mainboard received / sent over SPI. In turn, the display module drives the actual LCD screen and handles the interactions with the touchscreen.
What exactly is the higher-level protocol on top of go!bus, between Netduino Go and your display module? Are the drawing primitives related to common .NET abstractions?
I wrote a generic lightweight message serialization / deserialization system for passing messages / objects (in network byte order) between a C# app and the C code (and vice-versa) interpreting the commands. The buffer containing the serialized messages is used by SPI directly.
Could your display be used from a Gadgeteer mainboard as well, let's say through an SUX socket?
Yes, it should work just fine.
Thanks and looking forward to seeing the display in natura!
Thanks,
Cheers,
-Fabien.