How to change system clock frequency of tiva c launchpad using PLL on energia?

[amine 0]

hello,

i'm new here, and i want to know how to use PLL to change the tiva C systeme clock frequency?

thanks

[L.R.A 78]

Hi Amine,

I don't think there is a way to do that with Energia libraries. You have to use TivaWare libraries.

For that you need to include:

#include <stdint.h>
#include <stdbool.h>
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.c"

and I think I am not missing anything (I don't usually use the compiler that Energia uses).

Then this depends on which launchpad you have. Is it the smaller one? If it is just use:

SysCtlClockSet().

As an example for 80Mhz clock with the PLL, main oscillator with external 16Mhz crystal:

SysCtlClockSet(SYSCTL_SYSDIV_2_5|SYSCTL_USE_PLL|SYSCTL_OSC_MAIN|SYSCTL_XTAL_16MHZ);

For more info check this out:
https://sites.google.com/site/luiselectronicprojects/tutorials/tiva-tutorials/tm4c123-clock
 

[igor 163]

Depends on the chip family

 

TM4C1294

 

SysCtlClockFreqSet

 

On other family

 

SysCtlClockSet

 

These are the library calls in ROM or Tivaware.  If you want to see how to do it directly, look at the source code for those library routines.

[amine 0]

thank you guys for your answers