•Shortest possible interval is one machine cycle i.e., 1μs (using 12 MHz crystal frequency).
•An 8-bit counter can give maximum delay of 256μs because 28=256.
•A 13-bit counter can give maximum delay of 8192μs because 213=8192.
•A 16-bit counter can give maximum delay of 65536μs because 216=65536.
65536μs = 0.065536 sec = 0.066 sec (approx.)