external oscillators

amr_karimm said:

hi ,
i ask befor to feeding asmart card with oscllation clock by only on pin (xtal1) for at90s8515 i asked for have the clock from the pic which i use it to read the card
i want to know if i connect the pin of card with (xtal1) or (xtal2) of hte pic
thanks

Click to expand...

The PIC pins are clearly labelled on the data sheet, for example pin 15 of a 16F628 is labelled RA6/OSC2/CLKOUT, whereas pin 14 is labelled RA7/OSC1/CLKIN - so to feed the PIC oscillator to another device you would use CLKOUT. Bear in mind though that any heavy load will stop the oscillator.

thanks nigle ,
shoud i use a 74hc14 as a buffer for heavy loads

amr_karimm said:

thanks nigle ,
shoud i use a 74hc14 as a buffer for heavy loads

Click to expand...

I should try it first and see what happens!, it's quite possible the smart card is intended to be fed in this way.