On 9/13/06, genome wrote: > > hello, > I have a couple of hc18u quartz crystal oscillator.. and I could not find > datasheet on the net.. basically my problem is I dont know if they are > parallel cut or series cut crystal's... and what's recommended capacitor > C1 > C2 values to use and just incase they are strip cut crystal what Unfortunately, you need the data sheet. They may be parallel or series, may have low or high drive levels, and could require low to moderate capacitance, assuming they are parallel. They will almost certainly sing SOME sort of tune in a given circuit, but they might fracture from overdrive, or give just barely enough level to sort of run the circuit, most of the time. Giving cap values in uP app notes is just wrong, unless a particular crystal is specified. Generally speaking, for your standard parallel rock, double the Cl value, and subtract a few pF for strays and the chip itself.. If Cl in the xtal data sheet is 22pF, then 22*2 = 44, - 5pF gives 39pF on each side. The reason for this is from the crystal's point of view, the caps are in series. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist