external oscillators

[amr_karimm]

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

 

[Nigel Goodwin]

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

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.

 

[amr_karimm]

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

 

[Nigel Goodwin]

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

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