[Kris Verdeyen]

We had some issues keeping track of an encoder we used to close the loop around our steering control. It got to be very resource-intensive to count every edge transition, so we modified the code to only count every fourth encoder transition, which worked fine.

The problem, as Mark noted, is that the program hasn't returned from the interrupt service routine by the time that another interrupt comes along. This causes the processor to miss a count, which over time will lead to a large position error.

This will be the main type of problem that you'll see, especially if you try to close any high speed loops.