Hi Ed,
Instead of dividing by 9.9210 you can multiply by 0.100796 (1 / 9.9210). The number 6606 comes from 65536*0.100796=6606.

When you do something like 4947**6605 what happens is that PBP does 4947*6505 which internally results in a 32bit value, it then takes the middle 16bits of that 32bit result and return those 16bits to you. In effect that is the same thing as dividing the 32 bit result by 65536. If we do that with pen and paper we get, 4947*6605/65536=498 which is exactly what PBP will give you.

I guess you're not actually getting the period and pulsewidth i units of milliseconds? How do you measure it and what are the actual values you get. It best to work with the raw numbers for the calculations, internally any number can mean 50% or 8ms or whatever. It's only when the result must be presented to a human that you need to convert it into "real" units like ms or percent or whatever.

/Henrik.