int main(void){
  LL_Init();
  printf("Test1 \r\n");
  printf("Test2 \r\n");
  
  SystemClock_Config();

  while(1){
  printf("Test3 \r\n");
  printf("Test4 \r\n");
  }
  
}

void SystemClock_Config(void){

  LL_FLASH_SetLatency(LL_FLASH_LATENCY_4);

  if(LL_FLASH_GetLatency() != LL_FLASH_LATENCY_4){
  Error_Handler();
  }

  LL_PWR_SetRegulVoltageScaling(LL_PWR_REGU_VOLTAGE_SCALE1);

  //Enable HSI
  LL_RCC_HSI_Enable();
    // Wait till HSI is ready
  while(LL_RCC_HSI_IsReady() != 1);
  LL_RCC_HSI_SetCalibTrimming(16);

// Enable LSI
  LL_RCC_LSI_Enable();

   /* Wait till LSI is ready */
  while(LL_RCC_LSI_IsReady() != 1);


  LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSI, LL_RCC_PLLM_DIV_1, 10, LL_RCC_PLLR_DIV_2);
  LL_RCC_PLL_Enable();
  LL_RCC_PLL_EnableDomain_SYS();

   /* Wait till PLL is ready */
  while(LL_RCC_PLL_IsReady() != 1);

  LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_PLL);

   /* Wait till System clock is ready */
  while(LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_PLL);

  LL_RCC_SetAHBPrescaler(LL_RCC_SYSCLK_DIV_1);
  LL_RCC_SetAPB1Prescaler(LL_RCC_APB1_DIV_1);
  LL_RCC_SetAPB2Prescaler(LL_RCC_APB2_DIV_1);
  LL_Init1msTick(80000000);
  LL_SYSTICK_SetClkSource(LL_SYSTICK_CLKSOURCE_HCLK);
  LL_SetSystemCoreClock(80000000);

  LL_RCC_SetUSARTClockSource(LL_RCC_USART1_CLKSOURCE_SYSCLK);
  LL_RCC_SetI2CClockSource(LL_RCC_I2C1_CLKSOURCE_SYSCLK);

  /* SysTick_IRQn interrupt configuration */
  NVIC_SetPriority(SysTick_IRQn, NVIC_EncodePriority(NVIC_GetPriorityGrouping(),0, 0));
}