resolution: max 12287 pulses of 3÷32767 clock units wide each (i.e. 15 bits resolution); every pulse may have different width
clocks: 20 MHz (crystal controlled, 1 time unit = 50 ns; default),
1 MHz (crystal controlled, 1 time unit = 1 μs),
≤1kHz (software controlled, adjustable in multiples of 1 ms), external.
pulse width: min 150ns (with 20 MHz internal clock)