HyperbolicSpeed

Hyperbolic Speed

The PIC microcontrollers used in the RepRap project express timer and speed values as a number from 0 to 255.

When this is used to represent a speed, 0 is the slowest and 255 is the fastest. However these figures actually represent counter start values and don't correspond directly with physical speed. It is easiest to think of these in terms of delay, where you wait 256 - n time periods.

For example, a speed value of 255 will wait for a period of 256 - 255 = 1 time unit.

A speed value of 0 will wait for 256 - 0 = 256 time units. Note that this is actually moving and is not a physical speed of 0.

Also note that a speed of 255 is twice as fast as a speed of 254.

In general, to convert a speed value to a physical speed, use the following:

-- Main.SimonMcAuliffe - 03 Apr 2006