Smoothieware/Smoothieware — pull request #574 by PetteriAimonen (2014-12-29 09:58:34+00:00)
Title: Small fixes for the Spindle module.

- Now uses us_ticker_read(), leaving systick free for other uses.
- Sets lower priority for the pulse sensor interrupt.
- Added option for smoothing filter on the RPM readings, which
helps PID if the readings are noisy.