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Just a very quick question i expect everybody will know the answer to.

The delay librairies supplied with the compiler, if i use a 20Mhz clock and define this in a #pragma statement, if i then use

delay_s(2); will this give a delay of 2 seconds or are the delay functions defined for a 4mhz clock

ie does the #pragma statement compensate for the faster clock speed and adjust the values in the delay routine automatically

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Guest Pavel

The code for all delay functions is generated based on the clock rate #pragma. Only if there is no clock rate #pragma in the sources the delay code is generated based on 4MHz clock rate for the PIC targets and 50MHz for SX.

 

Regards,

Pavel

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Guest Talos

Ah that is what i thought, only it doesnt seem to accept that i have included a #pragma statement

 

I have this statement:

#pragma CLOCK_FREQ 20000000

 

but pulsing an led for delay_s(1); the led is on for less than a second. However if i increase the value in delay_s to 5 then the led is on for 1 second

 

If what you are saying is the pragma statement compensates then is it possible that the above line is being ignored.

Is there a way of checking in the compiled code that this statement is being acknowledged

 

The pic is a pic16f877 20mhz clock

 

Dave

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