Art and others, I have been very fasinated with Rutex SPI interface they have on their new breakout boards for their drives, I can quote a few things out of one of their pdf's:
http://www.rutex.com/pdf/R20x0.pdf"The SPI motion command is simply a
16-bit number of steps per each particular servo loop cycle (or quite often called as velocity word). Rather
then clocking each step individually, the host CNC tells the drive the number of step via SPI. For example,
with a 1ms loop-time, the maximum speed of SPI motion is +/-32767 steps/ms or 32,767,000 steps per
second."
"The SPI can be easily implemented in PC
using standard printer port (LPT) similar way as it is use for step&dir generation."
"The SPI is using 3
communication lines: clock, data-out and data-in. Clock and Data-out are same as Step and Dir signals."
Theres much more in that manual, such as controlling 7 axes with only 9 signal lines.
This is a communication interface that would be very useful for many rutex users, its one of the main things thats stopping me from buying their drives for my brushless servos, mainly because step/dir over the parallel port will be way slow for the high res encoders.
It sounds like Rutex is making a DLL or something like that for this interface, I along with many others are very intersted in seeing a package such as Mach software, even Mach 3 incorporated with SPI.
Thanks,
Jon