File content as of revision 2:f7a3163071b1:

/*
  ******************************************************************************
  * @file    SysClockConf.c
  * @version 
  * @date    05-July-2016
  * @brief   System Clock configuration for STM32F103C8T6
  *****************************************************************************
  *
  * All rights reserved.

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */

#include "SysClockConf.h"
#include "mbed.h"

void HSE_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_ON;
    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_MUL9;
    HAL_RCC_OscConfig(&RCC_OscInitStruct);
    RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
    RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
    RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
    HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2);
    PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_ADC|RCC_PERIPHCLK_USB;
    PeriphClkInit.AdcClockSelection = RCC_ADCPCLK2_DIV6;
    PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_PLL_DIV1_5;
    HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);
}

void confSysClock(void) {
    HAL_RCC_DeInit();
    HSE_SystemClock_Config();
    SystemCoreClockUpdate();
}