Microseconds - is a variable/constant (0-65535) which specifies how many multiples of 10 microseconds to pause (at 8MHz on X2 parts, else 4MHz).
Pause for some time.
The duration of the pause is as accurate as the resonator time-base, and presumes a 4MHz resonator (8MHz on X2 parts). The pauseus command creates a time delay (in multiples of 10 microseconds at 4MHz). As it takes a discrete amount of time to execute the command, small time delays may be inaccurate due to this 'overhead processing' time. This inaccuracy decreases as the delay gets longer.
Effect of increased clock speed
For non-X2 parts, the timebase is reduced to 5us at 8MHz and 2.5us at 16MHz. For X2 parts, the timebase is reduced to 5uS at 16MHz and 2.5uS at 32MHz.