clock frequency

praveen_karimilla · Joined: 30 Nov 2008 Posts: 8

how to set the clock frequency to 4mhz can any one help with PIC c

Rohit de Sa · Joined: 09 Nov 2007 Posts: 282 Location: India

The frequency of the PIC is set by the crystal attached to its OSC pins. If you put a 4MHz crystal, and set (one of) your fuses to 'XT', you can use this crystal.

Some PICs also have an internal oscillator preset at 4MHz, or a dual speed oscillator, or a selectable-speed oscillator. You need to use the 'INTRC' or 'INTRC_IO' fuses to do this.

If you have a multi-speed internal oscillator have a look at the 'setup_oscillator' instruction.

Rohit

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

Read the manual about the #use delay() preprocessor directive. It is simple for the older chips, but gets complex for the newer chips with many clock options. Also read clock section of the datasheet for your PIC.
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