STM32F334 USART2

void SystemClock_Config(void)

{

    RCC_OscInitTypeDef RCC_OscInitStruct;

    RCC_ClkInitTypeDef RCC_ClkInitStruct;

    RCC_PeriphCLKInitTypeDef PeriphClkInit;

    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;

    RCC_OscInitStruct.HSEState = RCC_HSE_BYPASS;

    RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;

    RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;

    RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;

    RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL8;

    HAL_RCC_OscConfig(&RCC_OscInitStruct);

    RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK

                                |RCC_CLOCKTYPE_PCLK1;

    RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;

    RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV2;

    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;

    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

    HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1);

    PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_HRTIM1|RCC_PERIPHCLK_USART2;

    PeriphClkInit.Usart2ClockSelection = RCC_USART2CLKSOURCE_PCLK1;

    PeriphClkInit.Hrtim1ClockSelection = RCC_HRTIM1CLK_PLLCLK;

    HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);

    HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);

    HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);

    __SYSCFG_CLK_ENABLE();

}

RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;

RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL16;