Using a different crystal oscillator

Guest · Posted: Tue Mar 15, 2005 3:05 pm

I have a PIC18f458 and was using a 20Mhz crystal oscillator. Will it make any difference in my program if I use a 16Mhz or 24Mhz oscillator?

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

You need to change the #use delay() statement to match your
new crystal frequency.

Mark · Joined: 07 Sep 2003 Posts: 2838 Location: Atlanta, GA

Depends on what your program does. It will affect the speed of your timers/counter/pwms. The baud rate generators will have different values as well. If you use the #use rs232 to set the speed then you won't have a problem. If you set the SPBRG value yourself, then you will have to compute the new value.