counter/ internal clock

[mister_e]

Yes it could be 1uSec / clock cycle @4MHZ... but not in Basic code, even in assembler @ 4MHZ, you couldn't do it @ 4MHZ with a software loop, hence why TIMERs are built in.

NOW, select a 16Bit timer that can be set as counter BY using the internal FOsc (ticks) and read the according register once in a while or in a loop. With some human measurement, you should be able to have a accuracy of few uSec.

This will also require you configure the Timer prescaler and pre-load value accordingly. To help you to figure out their value, i suggest you download my PicMutiCalc

http://www.mister-e.org/pages/utilitiespag.html

EDIT: it's sunday and my brain need to understand better what you need to do... i'm lost in your explanation. Maybe you could translate it to Mister E's poor english level?