Pulse counter does not reset timer prescaler before it starts counting

[Alexander Bessman]

The pulse counter uses timer2 to count pulses on a digital input. Some other functions also use timer2, notably the logic analyzer in four channel mode, which supports setting a prescaler to slow down the timer.

If a prescaler is set by the logic analyzer, the pulse counter will count slower than expected. It should reset the timer2 prescaler before it starts counting.