Carpokes Porsche Forum

The software solution is fine, he just needs to take care that his counters are big enough that low speeds don't overflow, plus handle the special case of 0 speed. He could probably treat anything under 5 MPH as zero and save some hassle. If the 30Hz low end is the barrier, the hardware solution could be made to work by slowing the system clock down by 4 or more, as long as the SPI port can be made to operate with that system clock speed (assuming 5 or below is 0.)

944er wrote: Sat Mar 23, 2024 6:24 pm The software solution is fine, he just needs to take care that his counters are big enough that low speeds don't overflow, plus handle the special case of 0 speed. He could probably treat anything under 5 MPH as zero and save some hassle. If the 30Hz low end is the barrier, the hardware solution could be made to work by slowing the system clock down by 4 or more, as long as the SPI port can be made to operate with that system clock speed (assuming 5 or below is 0.)

My code above was an early and simpler version of my SpeedoBooster code. I put a lot of effort into the 0 speed case for sure. That's a special challenge as the wheels start to slow toward zero. The speedometer itself (on the 944) does not handle sub 1-mph speeds very well either, compounding the issue. If it gets isolated pulses that are spaced too far apart, the speedometer will just bounce a little with each tick. I can't remember the speed I picked, but I ultimately decided it's better to kill all pulses if the speed is under like 1 or 2 mph...