Problem in getting 1 usec Interval Timer to work using NiosII and QSYS

Except that the 'timer component' is a 16bit slave (presumably it dates from the old 16bit nios) and it horribly expensive to access.

For polled interval timers you only need a single counter that is always running (without a zero function), the software just needs to read the 'start time' when it starts a timer.

For some uses you want to count clocks, for others divided down to usec, msec and seconds to avoid wrap issues for longer intervals.