[DFTF] Closing the loop on Wheel Velocity...

[EricVanWyk]

Originally Posted by theprgramerdude

It has a 50 MHz Cortex M-3. Unless the PID algorithm onboard is rather complex and heavy on the cycles, how could anything from a digital encoder approach the Jag's limits?

The Stellaris microcontroller does quadrature decoding in dedicated hardware, so there is no additional processing burden for running the encoders faster. The upper limit of that circuitry is 1/4th the speed of the processor. For a part running at 50MHz*, that is roughly 750,000 RPM for a 250 count encoder. However, I doubt you'd get clean signals from the poor encoder at those speeds!

The Stellaris has more computational horsepower available than the entire IFI control system put together several times over. It is an amazing show of what Moore's law does to the industry.

* Edit: I can't remember what speed they actually run on the Jag - there simply is no need to run at the full 50 or 80 MHz. Suffice it to say that it is still overkill.