> I must measure the input signal with 1 =B5s precision.

Doing that on a PIC while simultaneously doing other things is no
freshmans game. Consider
- dedicated hardware
- a dedicated PIC
- maybe even a (dedicated) Ubicom SX

NB a 16F runs at 5 MIPS @ 20 MHz maximum. An 18F runs at 10 MIPS at 40
MHz (10 MHz xtal with PLL * 4) maximum. An SX runs at 75 MIPS @ 75 MHz
maximum (or you might still be able to find 100 MHz SXes).

A SX is a clone of the older 12-bit PICs, but for simple timing tasks it
will run circles around any PIC. And any AVR. And probably most other
cheap microcontrollers. And maybe even some DSPs.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
=20

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