I think we are working on the same problem, just starting at different ends ;)
I still don't know if it will be XC-2 or XC-1 compatible. But most probably both. I think I will use the modular approach of the current projects on github. So that you got some serial communication module (for XC-1 and compatibility with current reprap PC software) - still undecided. Separated from that you will get the G-Code interpretation and separated from that the motion control.
I will first build a working tradtional reprap and reprap electronics. Then I will finish the TMC260 Library for Arduino and then port everything to XMOS.
It will most probably no the last time we discussed this ;)
Regarding the Trinamic drivers I really want to exploit two features of the drivers:
- The coolStep to reduce the power consumption.
- The stallguard to get away without endstops. It is a load measurement system. So it is very easy to detect when it cannot move any further. So it would be enough to have physical barriers instead of proper endstops. And you can calibrate the reprap more easily.