Setting CPU frequency for TIVA 129 Processor

Hi,

I am trying to set the CPU frequency as 80 MHz for tm4c129encpdt processor and I have set it in .cfg file as below:

1. Configuration file of bootloader is set as below:

// Set the CPU freq to match the PLL (80MHz)

BIOS.cpuFreq.lo = 80000000;

1. My reset function is set as below in .cfg file:

Startup.resetFxn = "&init_CPU";

In reset function, system clock is set to 80 MHz as below:

void init_CPU(void)

{

// Setting freq to 80 MHz.

clockFreq = SysCtlClockFreqSet(SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_CFG_VCO_480 | SYSCTL_XTAL_25MHZ, 80000000);

…

}

Runtime scenario:

Init_CPU function is called from startup code and it is set to 80 MHz and later startup code calls below function and it is set back to 120 MHz.

Void ti_catalog_arm_cortexm4_tiva_ce_Boot_init()

{

    ti_catalog_arm_cortexm4_tiva_ce_Boot_sysCtlClockFreqSet((ULong)

        (-251656576), (ULong)(120000000));

}

This function is auto generated and is available under _Debug folder, which means that compiler is getting input as 120 MHz. 

Is there any place other than .cfg file where we can set CPU frequency?

Regards

Srinivasa