Here is the current version of the CNC Shield for the Sparkfun XMOS Development board. I am going to have a few people review it before I buy it. I have the Sparkfun board on order and I will do so basic testing with it before I order too. The image below is not very useful. Use the PDF attachment. I just like to have a visual cue on each post so I can find stuff quickly.
Initially the code will be for engraving only. If you want to do G-Code cutting you will use your normal Mach3/EMC parallel port method. This board will connect in between the PC and CNC machine on the parallel port. This will allow you to use it in either mode without any wiring changes.
Basically it will operate in these modes.
- CNC Pass through. The signals just go through the board like it is not there. The XMOS sees all the signals, so it might be able to do some neat tricks even in this mode.
- Engrave mode. The XMOS controller runs via the USB port. The parallel port is still connected, but ignored. It does not have to ignore the parallel port in this mode, so some sort of Mach/EMC plugins could do some things here.
- TBD. There is no reason this could not turn into a junior version of a smoothstepper. It would have less I/O pins than a smoothstepper, but it plenty to control any machine that currently runs off a single parallel port
Edit: made a change to the schematic. Had some voltages wrong on the voltage translators.