*** Timings of the m8driver ***

These timings are based on a crystal frequency of 16MHz.


Name        | Value in nanoseconds  | Description
===============================================================================
steplen     | < 300                 | Minimum length of a step "high" pulse.
            |                       |
steptime    | < 2000                | Time required to process one step.
            |                       | So steps must be separated by this time,
            |                       | at least.
            |                       |
dirsetup    | < 100                 | Minimum spacing between a direction
            |                       | change and a step pulse.
            |                       |
dirhold     | < 0                   | Minimum time between end of step pulse
            |                       | and a direction change.