title: PLL clock configuration
body: <p>I'm using STM32L152RB board and I'm trying to configure system clock to use PLL clock but the RCC_FLAG_PLLRDY flag is getting set so the program is stuck in while loop. please let what I'm doing wrong</p>
  
  <pre><code>EnableHSI();
  RCC_PLLConfig(RCC_PLLSource_HSI,RCC_PLLMul_3,RCC_PLLDiv_2);
  RCC_PLLCmd(ENABLE);
  while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);
  RCC_SYSCLKConfig( RCC_SYSCLKSource_PLLCLK);
  t=GetSystemClockSource();
  </code></pre>