Hi,
Make use of "GpioToggle" sample code from controlSuite. Remove delays during toggling and configure PLL as following:
// Setup the PLL for x12 /2 which will yield 60Mhz = 10Mhz * 12 / 2 PLL_setup(myPll, PLL_Multiplier_12, PLL_DivideSelect_ClkIn_by_2);
This is the maximum setting as Launchpad operating frequency is 60MHz.
Check the waveform on DSO and revert. Good Luck.
Regards,
Gautam