[6600gt]

Sorry I ment the clock speed is 40 MHz but the timer incriments one every 4 of them. Same with the processor instructions cycle. It is 1/4 the speed of the clock.

The example has a 10MHz clock but but the acutal ticks on the timer are only 2.5 MHz so per second(assuming 1 to 1 prescale). So on the robot controller you have to multiply that number by 4 to get the real number of ticks per second( If you are going by the example in Kevin Watson's interrupt code or the data sheets).