mbed library sources

Dependents:   frdm_kl05z_gpio_test

Fork of mbed-src by mbed official

Revision:
139:e3413eddde57
Parent:
84:f54042cbc282
Child:
167:d5744491c362
diff -r ec7ee4660c49 -r e3413eddde57 targets/cmsis/TARGET_STM/TARGET_NUCLEO_F103RB/system_stm32f10x.c
--- a/targets/cmsis/TARGET_STM/TARGET_NUCLEO_F103RB/system_stm32f10x.c	Tue Mar 25 17:45:07 2014 +0000
+++ b/targets/cmsis/TARGET_STM/TARGET_NUCLEO_F103RB/system_stm32f10x.c	Thu Mar 27 09:45:07 2014 +0000
@@ -35,7 +35,23 @@
   *    When HSE is used as system clock source, directly or through PLL, and you
   *    are using different crystal you have to adapt the HSE value to your own
   *    configuration.
-  *        
+  * 5. This file configures the system clock as follows:
+  *-----------------------------------------------------------------------------
+  * System clock source                | 1- PLL_HSE_EXTC        | 3- PLL_HSI
+  *                                    | (external 8 MHz clock) | (internal 8 MHz)
+  *                                    | 2- PLL_HSE_XTAL        |
+  *                                    | (external 8 MHz xtal)  |
+  *-----------------------------------------------------------------------------
+  * SYSCLK(MHz)                        | 72                     | 64
+  *-----------------------------------------------------------------------------
+  * AHBCLK (MHz)                       | 72                     | 64
+  *-----------------------------------------------------------------------------
+  * APB1CLK (MHz)                      | 36                     | 32
+  *-----------------------------------------------------------------------------
+  * APB2CLK (MHz)                      | 72                     | 64
+  *-----------------------------------------------------------------------------
+  * USB capable (48 MHz precise clock) | YES                    | NO
+  *-----------------------------------------------------------------------------  
  *******************************************************************************
  * Copyright (c) 2014, STMicroelectronics
  * All rights reserved.
@@ -95,55 +111,11 @@
   * @{
   */
 
-/*!< Uncomment the line corresponding to the desired System clock (SYSCLK)
-   frequency (after reset the HSI is used as SYSCLK source)
-   
-   IMPORTANT NOTE:
-   ============== 
-   1. After each device reset the HSI is used as System clock source.
-
-   2. Please make sure that the selected System clock doesn't exceed your device's
-      maximum frequency.
-      
-   3. If none of the define below is enabled, the HSI is used as System clock
-    source.
-
-   4. The System clock configuration functions provided within this file assume that:
-        - For Low, Medium and High density Value line devices an external 8MHz 
-          crystal is used to drive the System clock.
-        - For Low, Medium and High density devices an external 8MHz crystal is
-          used to drive the System clock.
-        - For Connectivity line devices an external 25MHz crystal is used to drive
-          the System clock.
-     If you are using different crystal you have to adapt those functions accordingly.
-    */
-    
-#if defined (STM32F10X_LD_VL) || (defined STM32F10X_MD_VL) || (defined STM32F10X_HD_VL)
-/* #define SYSCLK_FREQ_HSE    HSE_VALUE */
-/* #define SYSCLK_FREQ_24MHz  24000000 */
-#else
-/* #define SYSCLK_FREQ_HSE    HSE_VALUE */
-/* #define SYSCLK_FREQ_24MHz  24000000 */ 
-/* #define SYSCLK_FREQ_36MHz  36000000 */
-/* #define SYSCLK_FREQ_48MHz  48000000 */
-/* #define SYSCLK_FREQ_56MHz  56000000 */
-/* #define SYSCLK_FREQ_72MHz  72000000 */
-#endif
-
-/*!< Uncomment the following line if you need to use external SRAM mounted
-     on STM3210E-EVAL board (STM32 High density and XL-density devices) or on 
-     STM32100E-EVAL board (STM32 High-density value line devices) as data memory */ 
-#if defined (STM32F10X_HD) || (defined STM32F10X_XL) || (defined STM32F10X_HD_VL)
-/* #define DATA_IN_ExtSRAM */
-#endif
-
 /*!< Uncomment the following line if you need to relocate your vector Table in
      Internal SRAM. */ 
 /* #define VECT_TAB_SRAM */
 #define VECT_TAB_OFFSET  0x0 /*!< Vector Table base offset field. 
                                   This value must be a multiple of 0x200. */
-
-
 /**
   * @}
   */
@@ -152,6 +124,10 @@
   * @{
   */
 
+/* Select the clock sources (other than HSI) to start with (0=OFF, 1=ON) */
+#define USE_PLL_HSE_EXTC (1) /* Use external clock */
+#define USE_PLL_HSE_XTAL (1) /* Use external xtal */
+
 /**
   * @}
   */
@@ -160,24 +136,7 @@
   * @{
   */
 
-/*******************************************************************************
-*  Clock Definitions
-*******************************************************************************/
-#ifdef SYSCLK_FREQ_HSE
-  uint32_t SystemCoreClock         = SYSCLK_FREQ_HSE;        /*!< System Clock Frequency (Core Clock) */
-#elif defined SYSCLK_FREQ_24MHz
-  uint32_t SystemCoreClock         = SYSCLK_FREQ_24MHz;        /*!< System Clock Frequency (Core Clock) */
-#elif defined SYSCLK_FREQ_36MHz
-  uint32_t SystemCoreClock         = SYSCLK_FREQ_36MHz;        /*!< System Clock Frequency (Core Clock) */
-#elif defined SYSCLK_FREQ_48MHz
-  uint32_t SystemCoreClock         = SYSCLK_FREQ_48MHz;        /*!< System Clock Frequency (Core Clock) */
-#elif defined SYSCLK_FREQ_56MHz
-  uint32_t SystemCoreClock         = SYSCLK_FREQ_56MHz;        /*!< System Clock Frequency (Core Clock) */
-#elif defined SYSCLK_FREQ_72MHz
-  uint32_t SystemCoreClock         = SYSCLK_FREQ_72MHz;        /*!< System Clock Frequency (Core Clock) */
-#else /*!< HSI Selected as System Clock source */
-  uint32_t SystemCoreClock         = HSI_VALUE;        /*!< System Clock Frequency (Core Clock) */
-#endif
+uint32_t SystemCoreClock = 64000000; /* Default with HSI. Will be updated if HSE is used */
 
 __I uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 /**
@@ -188,22 +147,14 @@
   * @{
   */
 
-static void SetSysClock(void);
+void SetSysClock(void);
 
-#ifdef SYSCLK_FREQ_HSE
-  static void SetSysClockToHSE(void);
-#elif defined SYSCLK_FREQ_24MHz
-  static void SetSysClockTo24(void);
-#elif defined SYSCLK_FREQ_36MHz
-  static void SetSysClockTo36(void);
-#elif defined SYSCLK_FREQ_48MHz
-  static void SetSysClockTo48(void);
-#elif defined SYSCLK_FREQ_56MHz
-  static void SetSysClockTo56(void);  
-#elif defined SYSCLK_FREQ_72MHz
-  static void SetSysClockTo72(void);
+#if (USE_PLL_HSE_XTAL != 0) || (USE_PLL_HSE_EXTC != 0)
+uint8_t SetSysClock_PLL_HSE(uint8_t bypass);
 #endif
 
+uint8_t SetSysClock_PLL_HSI(void);
+
 #ifdef DATA_IN_ExtSRAM
   static void SystemInit_ExtMemCtl(void); 
 #endif /* DATA_IN_ExtSRAM */
@@ -431,24 +382,41 @@
   * @param  None
   * @retval None
   */
-static void SetSysClock(void)
+void SetSysClock(void)
 {
-#ifdef SYSCLK_FREQ_HSE
-  SetSysClockToHSE();
-#elif defined SYSCLK_FREQ_24MHz
-  SetSysClockTo24();
-#elif defined SYSCLK_FREQ_36MHz
-  SetSysClockTo36();
-#elif defined SYSCLK_FREQ_48MHz
-  SetSysClockTo48();
-#elif defined SYSCLK_FREQ_56MHz
-  SetSysClockTo56();  
-#elif defined SYSCLK_FREQ_72MHz
-  SetSysClockTo72();
+  /* 1- Try to start with HSE and external clock */
+#if USE_PLL_HSE_EXTC != 0
+  if (SetSysClock_PLL_HSE(1) == 0)
 #endif
- 
- /* If none of the define above is enabled, the HSI is used as System clock
-    source (default after reset) */ 
+  {
+    /* 2- If fail try to start with HSE and external xtal */
+    #if USE_PLL_HSE_XTAL != 0
+    if (SetSysClock_PLL_HSE(0) == 0)
+    #endif
+    {
+      /* 3- If fail start with HSI clock */
+      if (SetSysClock_PLL_HSI() == 0)
+      {
+        while(1)
+        {
+          // [TODO] Put something here to tell the user that a problem occured...
+        }
+      }
+    }
+  }
+  
+  /* Output SYSCLK on MCO pin(PA8) for debugging purpose */
+  /*
+  // Enable GPIOA clock
+  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
+  GPIO_InitTypeDef GPIO_InitStructure;
+  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_8;
+  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF_PP;
+  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
+  GPIO_Init(GPIOA, &GPIO_InitStructure);
+  // Select the clock to output
+  RCC_MCOConfig(RCC_MCO_SYSCLK);
+  */
 }
 
 /**
@@ -504,572 +472,57 @@
 }
 #endif /* DATA_IN_ExtSRAM */
 
-#ifdef SYSCLK_FREQ_HSE
-/**
-  * @brief  Selects HSE as System clock source and configure HCLK, PCLK2
-  *         and PCLK1 prescalers.
-  * @note   This function should be used only after reset.
-  * @param  None
-  * @retval None
-  */
-static void SetSysClockToHSE(void)
+#if (USE_PLL_HSE_XTAL != 0) || (USE_PLL_HSE_EXTC != 0)
+/******************************************************************************/
+/*            PLL (clocked by HSE) used as System clock source                */
+/******************************************************************************/
+uint8_t SetSysClock_PLL_HSE(uint8_t bypass)
 {
-  __IO uint32_t StartUpCounter = 0, HSEStatus = 0;
-  
-  /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration ---------------------------*/    
-  /* Enable HSE */    
-  RCC->CR |= ((uint32_t)RCC_CR_HSEON);
- 
-  /* Wait till HSE is ready and if Time out is reached exit */
-  do
-  {
-    HSEStatus = RCC->CR & RCC_CR_HSERDY;
-    StartUpCounter++;  
-  } while((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT));
-
-  if ((RCC->CR & RCC_CR_HSERDY) != RESET)
-  {
-    HSEStatus = (uint32_t)0x01;
-  }
-  else
-  {
-    HSEStatus = (uint32_t)0x00;
-  }  
-
-  if (HSEStatus == (uint32_t)0x01)
-  {
-
-#if !defined STM32F10X_LD_VL && !defined STM32F10X_MD_VL && !defined STM32F10X_HD_VL
-    /* Enable Prefetch Buffer */
-    FLASH->ACR |= FLASH_ACR_PRFTBE;
-
-    /* Flash 0 wait state */
-    FLASH->ACR &= (uint32_t)((uint32_t)~FLASH_ACR_LATENCY);
+  __IO uint32_t StartUpCounter = 0;
+  __IO uint32_t HSEStatus = 0;
 
-#ifndef STM32F10X_CL
-    FLASH->ACR |= (uint32_t)FLASH_ACR_LATENCY_0;
-#else
-    if (HSE_VALUE <= 24000000)
-	{
-      FLASH->ACR |= (uint32_t)FLASH_ACR_LATENCY_0;
-	}
-	else
-	{
-      FLASH->ACR |= (uint32_t)FLASH_ACR_LATENCY_1;
-	}
-#endif /* STM32F10X_CL */
-#endif
- 
-    /* HCLK = SYSCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
-      
-    /* PCLK2 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
-    
-    /* PCLK1 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV1;
-    
-    /* Select HSE as system clock source */
-    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
-    RCC->CFGR |= (uint32_t)RCC_CFGR_SW_HSE;    
-
-    /* Wait till HSE is used as system clock source */
-    while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)0x04)
-    {
-    }
-  }
-  else
-  { /* If HSE fails to start-up, the application will have wrong clock 
-         configuration. User can add here some code to deal with this error */
-  }  
-}
-#elif defined SYSCLK_FREQ_24MHz
-/**
-  * @brief  Sets System clock frequency to 24MHz and configure HCLK, PCLK2 
-  *         and PCLK1 prescalers.
-  * @note   This function should be used only after reset.
-  * @param  None
-  * @retval None
-  */
-static void SetSysClockTo24(void)
-{
-  __IO uint32_t StartUpCounter = 0, HSEStatus = 0;
-  
-  /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration ---------------------------*/    
-  /* Enable HSE */    
-  RCC->CR |= ((uint32_t)RCC_CR_HSEON);
- 
-  /* Wait till HSE is ready and if Time out is reached exit */
-  do
+  /* Bypass HSE: can be done only if HSE is OFF */
+  RCC->CR &= ((uint32_t)~RCC_CR_HSEON); /* To be sure HSE is OFF */  
+  if (bypass != 0)
   {
-    HSEStatus = RCC->CR & RCC_CR_HSERDY;
-    StartUpCounter++;  
-  } while((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT));
-
-  if ((RCC->CR & RCC_CR_HSERDY) != RESET)
-  {
-    HSEStatus = (uint32_t)0x01;
+    RCC->CR |= ((uint32_t)RCC_CR_HSEBYP);
   }
   else
   {
-    HSEStatus = (uint32_t)0x00;
-  }  
-
-  if (HSEStatus == (uint32_t)0x01)
-  {
-#if !defined STM32F10X_LD_VL && !defined STM32F10X_MD_VL && !defined STM32F10X_HD_VL 
-    /* Enable Prefetch Buffer */
-    FLASH->ACR |= FLASH_ACR_PRFTBE;
-
-    /* Flash 0 wait state */
-    FLASH->ACR &= (uint32_t)((uint32_t)~FLASH_ACR_LATENCY);
-    FLASH->ACR |= (uint32_t)FLASH_ACR_LATENCY_0;    
-#endif
- 
-    /* HCLK = SYSCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
-      
-    /* PCLK2 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
-    
-    /* PCLK1 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV1;
-    
-#ifdef STM32F10X_CL
-    /* Configure PLLs ------------------------------------------------------*/
-    /* PLL configuration: PLLCLK = PREDIV1 * 6 = 24 MHz */ 
-    RCC->CFGR &= (uint32_t)~(RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLSRC | RCC_CFGR_PLLMULL);
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLXTPRE_PREDIV1 | RCC_CFGR_PLLSRC_PREDIV1 | 
-                            RCC_CFGR_PLLMULL6); 
-
-    /* PLL2 configuration: PLL2CLK = (HSE / 5) * 8 = 40 MHz */
-    /* PREDIV1 configuration: PREDIV1CLK = PLL2 / 10 = 4 MHz */       
-    RCC->CFGR2 &= (uint32_t)~(RCC_CFGR2_PREDIV2 | RCC_CFGR2_PLL2MUL |
-                              RCC_CFGR2_PREDIV1 | RCC_CFGR2_PREDIV1SRC);
-    RCC->CFGR2 |= (uint32_t)(RCC_CFGR2_PREDIV2_DIV5 | RCC_CFGR2_PLL2MUL8 |
-                             RCC_CFGR2_PREDIV1SRC_PLL2 | RCC_CFGR2_PREDIV1_DIV10);
+    RCC->CR &= ((uint32_t)~RCC_CR_HSEBYP);
+  }
   
-    /* Enable PLL2 */
-    RCC->CR |= RCC_CR_PLL2ON;
-    /* Wait till PLL2 is ready */
-    while((RCC->CR & RCC_CR_PLL2RDY) == 0)
-    {
-    }   
-#elif defined (STM32F10X_LD_VL) || defined (STM32F10X_MD_VL) || defined (STM32F10X_HD_VL)
-    /*  PLL configuration:  = (HSE / 2) * 6 = 24 MHz */
-    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL));
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_PREDIV1 | RCC_CFGR_PLLXTPRE_PREDIV1_Div2 | RCC_CFGR_PLLMULL6);
-#else    
-    /*  PLL configuration:  = (HSE / 2) * 6 = 24 MHz */
-    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL));
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLXTPRE_HSE_Div2 | RCC_CFGR_PLLMULL6);
-#endif /* STM32F10X_CL */
-
-    /* Enable PLL */
-    RCC->CR |= RCC_CR_PLLON;
-
-    /* Wait till PLL is ready */
-    while((RCC->CR & RCC_CR_PLLRDY) == 0)
-    {
-    }
-
-    /* Select PLL as system clock source */
-    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
-    RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;    
-
-    /* Wait till PLL is used as system clock source */
-    while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)0x08)
-    {
-    }
-  }
-  else
-  { /* If HSE fails to start-up, the application will have wrong clock 
-         configuration. User can add here some code to deal with this error */
-  } 
-}
-#elif defined SYSCLK_FREQ_36MHz
-/**
-  * @brief  Sets System clock frequency to 36MHz and configure HCLK, PCLK2 
-  *         and PCLK1 prescalers. 
-  * @note   This function should be used only after reset.
-  * @param  None
-  * @retval None
-  */
-static void SetSysClockTo36(void)
-{
-  __IO uint32_t StartUpCounter = 0, HSEStatus = 0;
+  /* Enable HSE */
+  RCC->CR |= ((uint32_t)RCC_CR_HSEON);
   
-  /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration ---------------------------*/    
-  /* Enable HSE */    
-  RCC->CR |= ((uint32_t)RCC_CR_HSEON);
- 
-  /* Wait till HSE is ready and if Time out is reached exit */
+  /* Wait till HSE is ready */
   do
   {
     HSEStatus = RCC->CR & RCC_CR_HSERDY;
-    StartUpCounter++;  
+    StartUpCounter++;
   } while((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT));
 
+  /* Check if HSE has started correctly */
   if ((RCC->CR & RCC_CR_HSERDY) != RESET)
   {
-    HSEStatus = (uint32_t)0x01;
-  }
-  else
-  {
-    HSEStatus = (uint32_t)0x00;
-  }  
-
-  if (HSEStatus == (uint32_t)0x01)
-  {
     /* Enable Prefetch Buffer */
     FLASH->ACR |= FLASH_ACR_PRFTBE;
 
-    /* Flash 1 wait state */
+    /* Flash wait states
+       0WS for 0  < SYSCLK <= 24 MHz
+       1WS for 24 < SYSCLK <= 48 MHz
+       2WS for 48 < SYSCLK <= 72 MHz */
     FLASH->ACR &= (uint32_t)((uint32_t)~FLASH_ACR_LATENCY);
-    FLASH->ACR |= (uint32_t)FLASH_ACR_LATENCY_1;    
- 
-    /* HCLK = SYSCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
-      
-    /* PCLK2 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
-    
-    /* PCLK1 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV1;
-    
-#ifdef STM32F10X_CL
-    /* Configure PLLs ------------------------------------------------------*/
-    
-    /* PLL configuration: PLLCLK = PREDIV1 * 9 = 36 MHz */ 
-    RCC->CFGR &= (uint32_t)~(RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLSRC | RCC_CFGR_PLLMULL);
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLXTPRE_PREDIV1 | RCC_CFGR_PLLSRC_PREDIV1 | 
-                            RCC_CFGR_PLLMULL9); 
-
-	/*!< PLL2 configuration: PLL2CLK = (HSE / 5) * 8 = 40 MHz */
-    /* PREDIV1 configuration: PREDIV1CLK = PLL2 / 10 = 4 MHz */
-        
-    RCC->CFGR2 &= (uint32_t)~(RCC_CFGR2_PREDIV2 | RCC_CFGR2_PLL2MUL |
-                              RCC_CFGR2_PREDIV1 | RCC_CFGR2_PREDIV1SRC);
-    RCC->CFGR2 |= (uint32_t)(RCC_CFGR2_PREDIV2_DIV5 | RCC_CFGR2_PLL2MUL8 |
-                             RCC_CFGR2_PREDIV1SRC_PLL2 | RCC_CFGR2_PREDIV1_DIV10);
-  
-    /* Enable PLL2 */
-    RCC->CR |= RCC_CR_PLL2ON;
-    /* Wait till PLL2 is ready */
-    while((RCC->CR & RCC_CR_PLL2RDY) == 0)
-    {
-    }
-    
-#else    
-    /*  PLL configuration: PLLCLK = (HSE / 2) * 9 = 36 MHz */
-    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL));
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLXTPRE_HSE_Div2 | RCC_CFGR_PLLMULL9);
-#endif /* STM32F10X_CL */
-
-    /* Enable PLL */
-    RCC->CR |= RCC_CR_PLLON;
-
-    /* Wait till PLL is ready */
-    while((RCC->CR & RCC_CR_PLLRDY) == 0)
-    {
-    }
-
-    /* Select PLL as system clock source */
-    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
-    RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;    
-
-    /* Wait till PLL is used as system clock source */
-    while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)0x08)
-    {
-    }
-  }
-  else
-  { /* If HSE fails to start-up, the application will have wrong clock 
-         configuration. User can add here some code to deal with this error */
-  } 
-}
-#elif defined SYSCLK_FREQ_48MHz
-/**
-  * @brief  Sets System clock frequency to 48MHz and configure HCLK, PCLK2 
-  *         and PCLK1 prescalers. 
-  * @note   This function should be used only after reset.
-  * @param  None
-  * @retval None
-  */
-static void SetSysClockTo48(void)
-{
-  __IO uint32_t StartUpCounter = 0, HSEStatus = 0;
-  
-  /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration ---------------------------*/    
-  /* Enable HSE */    
-  RCC->CR |= ((uint32_t)RCC_CR_HSEON);
- 
-  /* Wait till HSE is ready and if Time out is reached exit */
-  do
-  {
-    HSEStatus = RCC->CR & RCC_CR_HSERDY;
-    StartUpCounter++;  
-  } while((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT));
-
-  if ((RCC->CR & RCC_CR_HSERDY) != RESET)
-  {
-    HSEStatus = (uint32_t)0x01;
-  }
-  else
-  {
-    HSEStatus = (uint32_t)0x00;
-  }  
-
-  if (HSEStatus == (uint32_t)0x01)
-  {
-    /* Enable Prefetch Buffer */
-    FLASH->ACR |= FLASH_ACR_PRFTBE;
-
-    /* Flash 1 wait state */
-    FLASH->ACR &= (uint32_t)((uint32_t)~FLASH_ACR_LATENCY);
-    FLASH->ACR |= (uint32_t)FLASH_ACR_LATENCY_1;    
- 
-    /* HCLK = SYSCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
-      
-    /* PCLK2 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
-    
-    /* PCLK1 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV2;
-    
-#ifdef STM32F10X_CL
-    /* Configure PLLs ------------------------------------------------------*/
-    /* PLL2 configuration: PLL2CLK = (HSE / 5) * 8 = 40 MHz */
-    /* PREDIV1 configuration: PREDIV1CLK = PLL2 / 5 = 8 MHz */
-        
-    RCC->CFGR2 &= (uint32_t)~(RCC_CFGR2_PREDIV2 | RCC_CFGR2_PLL2MUL |
-                              RCC_CFGR2_PREDIV1 | RCC_CFGR2_PREDIV1SRC);
-    RCC->CFGR2 |= (uint32_t)(RCC_CFGR2_PREDIV2_DIV5 | RCC_CFGR2_PLL2MUL8 |
-                             RCC_CFGR2_PREDIV1SRC_PLL2 | RCC_CFGR2_PREDIV1_DIV5);
-  
-    /* Enable PLL2 */
-    RCC->CR |= RCC_CR_PLL2ON;
-    /* Wait till PLL2 is ready */
-    while((RCC->CR & RCC_CR_PLL2RDY) == 0)
-    {
-    }
-    
-   
-    /* PLL configuration: PLLCLK = PREDIV1 * 6 = 48 MHz */ 
-    RCC->CFGR &= (uint32_t)~(RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLSRC | RCC_CFGR_PLLMULL);
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLXTPRE_PREDIV1 | RCC_CFGR_PLLSRC_PREDIV1 | 
-                            RCC_CFGR_PLLMULL6); 
-#else    
-    /*  PLL configuration: PLLCLK = HSE * 6 = 48 MHz */
-    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL));
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMULL6);
-#endif /* STM32F10X_CL */
-
-    /* Enable PLL */
-    RCC->CR |= RCC_CR_PLLON;
-
-    /* Wait till PLL is ready */
-    while((RCC->CR & RCC_CR_PLLRDY) == 0)
-    {
-    }
-
-    /* Select PLL as system clock source */
-    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
-    RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;    
-
-    /* Wait till PLL is used as system clock source */
-    while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)0x08)
-    {
-    }
-  }
-  else
-  { /* If HSE fails to start-up, the application will have wrong clock 
-         configuration. User can add here some code to deal with this error */
-  } 
-}
+    FLASH->ACR |= (uint32_t)FLASH_ACR_LATENCY_2; 
 
-#elif defined SYSCLK_FREQ_56MHz
-/**
-  * @brief  Sets System clock frequency to 56MHz and configure HCLK, PCLK2 
-  *         and PCLK1 prescalers. 
-  * @note   This function should be used only after reset.
-  * @param  None
-  * @retval None
-  */
-static void SetSysClockTo56(void)
-{
-  __IO uint32_t StartUpCounter = 0, HSEStatus = 0;
-  
-  /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration ---------------------------*/   
-  /* Enable HSE */    
-  RCC->CR |= ((uint32_t)RCC_CR_HSEON);
- 
-  /* Wait till HSE is ready and if Time out is reached exit */
-  do
-  {
-    HSEStatus = RCC->CR & RCC_CR_HSERDY;
-    StartUpCounter++;  
-  } while((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT));
-
-  if ((RCC->CR & RCC_CR_HSERDY) != RESET)
-  {
-    HSEStatus = (uint32_t)0x01;
-  }
-  else
-  {
-    HSEStatus = (uint32_t)0x00;
-  }  
-
-  if (HSEStatus == (uint32_t)0x01)
-  {
-    /* Enable Prefetch Buffer */
-    FLASH->ACR |= FLASH_ACR_PRFTBE;
-
-    /* Flash 2 wait state */
-    FLASH->ACR &= (uint32_t)((uint32_t)~FLASH_ACR_LATENCY);
-    FLASH->ACR |= (uint32_t)FLASH_ACR_LATENCY_2;    
- 
-    /* HCLK = SYSCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
-      
-    /* PCLK2 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
-    
-    /* PCLK1 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV2;
-
-#ifdef STM32F10X_CL
-    /* Configure PLLs ------------------------------------------------------*/
-    /* PLL2 configuration: PLL2CLK = (HSE / 5) * 8 = 40 MHz */
-    /* PREDIV1 configuration: PREDIV1CLK = PLL2 / 5 = 8 MHz */
-        
-    RCC->CFGR2 &= (uint32_t)~(RCC_CFGR2_PREDIV2 | RCC_CFGR2_PLL2MUL |
-                              RCC_CFGR2_PREDIV1 | RCC_CFGR2_PREDIV1SRC);
-    RCC->CFGR2 |= (uint32_t)(RCC_CFGR2_PREDIV2_DIV5 | RCC_CFGR2_PLL2MUL8 |
-                             RCC_CFGR2_PREDIV1SRC_PLL2 | RCC_CFGR2_PREDIV1_DIV5);
-  
-    /* Enable PLL2 */
-    RCC->CR |= RCC_CR_PLL2ON;
-    /* Wait till PLL2 is ready */
-    while((RCC->CR & RCC_CR_PLL2RDY) == 0)
-    {
-    }
-    
-   
-    /* PLL configuration: PLLCLK = PREDIV1 * 7 = 56 MHz */ 
-    RCC->CFGR &= (uint32_t)~(RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLSRC | RCC_CFGR_PLLMULL);
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLXTPRE_PREDIV1 | RCC_CFGR_PLLSRC_PREDIV1 | 
-                            RCC_CFGR_PLLMULL7); 
-#else     
-    /* PLL configuration: PLLCLK = HSE * 7 = 56 MHz */
+    /* PLL configuration */
+    /* SYSCLK = 72 MHz (8 MHz * 9) */
     RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL));
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMULL7);
-
-#endif /* STM32F10X_CL */
-
-    /* Enable PLL */
-    RCC->CR |= RCC_CR_PLLON;
-
-    /* Wait till PLL is ready */
-    while((RCC->CR & RCC_CR_PLLRDY) == 0)
-    {
-    }
-
-    /* Select PLL as system clock source */
-    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
-    RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;    
-
-    /* Wait till PLL is used as system clock source */
-    while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)0x08)
-    {
-    }
-  }
-  else
-  { /* If HSE fails to start-up, the application will have wrong clock 
-         configuration. User can add here some code to deal with this error */
-  } 
-}
-
-#elif defined SYSCLK_FREQ_72MHz
-/**
-  * @brief  Sets System clock frequency to 72MHz and configure HCLK, PCLK2 
-  *         and PCLK1 prescalers. 
-  * @note   This function should be used only after reset.
-  * @param  None
-  * @retval None
-  */
-static void SetSysClockTo72(void)
-{
-  __IO uint32_t StartUpCounter = 0, HSEStatus = 0;
-  
-  /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration ---------------------------*/    
-  /* Enable HSE */    
-  RCC->CR |= ((uint32_t)RCC_CR_HSEON);
- 
-  /* Wait till HSE is ready and if Time out is reached exit */
-  do
-  {
-    HSEStatus = RCC->CR & RCC_CR_HSERDY;
-    StartUpCounter++;  
-  } while((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT));
-
-  if ((RCC->CR & RCC_CR_HSERDY) != RESET)
-  {
-    HSEStatus = (uint32_t)0x01;
-  }
-  else
-  {
-    HSEStatus = (uint32_t)0x00;
-  }  
-
-  if (HSEStatus == (uint32_t)0x01)
-  {
-    /* Enable Prefetch Buffer */
-    FLASH->ACR |= FLASH_ACR_PRFTBE;
-
-    /* Flash 2 wait state */
-    FLASH->ACR &= (uint32_t)((uint32_t)~FLASH_ACR_LATENCY);
-    FLASH->ACR |= (uint32_t)FLASH_ACR_LATENCY_2;    
-
- 
-    /* HCLK = SYSCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
-      
-    /* PCLK2 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
-    
-    /* PCLK1 = HCLK */
-    RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV2;
-
-#ifdef STM32F10X_CL
-    /* Configure PLLs ------------------------------------------------------*/
-    /* PLL2 configuration: PLL2CLK = (HSE / 5) * 8 = 40 MHz */
-    /* PREDIV1 configuration: PREDIV1CLK = PLL2 / 5 = 8 MHz */
-        
-    RCC->CFGR2 &= (uint32_t)~(RCC_CFGR2_PREDIV2 | RCC_CFGR2_PLL2MUL |
-                              RCC_CFGR2_PREDIV1 | RCC_CFGR2_PREDIV1SRC);
-    RCC->CFGR2 |= (uint32_t)(RCC_CFGR2_PREDIV2_DIV5 | RCC_CFGR2_PLL2MUL8 |
-                             RCC_CFGR2_PREDIV1SRC_PLL2 | RCC_CFGR2_PREDIV1_DIV5);
-  
-    /* Enable PLL2 */
-    RCC->CR |= RCC_CR_PLL2ON;
-    /* Wait till PLL2 is ready */
-    while((RCC->CR & RCC_CR_PLL2RDY) == 0)
-    {
-    }
-    
-   
-    /* PLL configuration: PLLCLK = PREDIV1 * 9 = 72 MHz */ 
-    RCC->CFGR &= (uint32_t)~(RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLSRC | RCC_CFGR_PLLMULL);
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLXTPRE_PREDIV1 | RCC_CFGR_PLLSRC_PREDIV1 | 
-                            RCC_CFGR_PLLMULL9); 
-#else    
-    /*  PLL configuration: PLLCLK = HSE * 9 = 72 MHz */
-    RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE |
-                                        RCC_CFGR_PLLMULL));
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMULL9);
-#endif /* STM32F10X_CL */
+    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMULL9
+                          | RCC_CFGR_HPRE_DIV1    /* HCLK   = 72 MHz */
+                          | RCC_CFGR_PPRE2_DIV1   /* PCLK2  = 72 MHz */
+                          | RCC_CFGR_PPRE1_DIV2); /* PCLK1  = 36 MHz */
+                                                  /* USBCLK = 48 MHz (72 MHz / 1.5) --> USB OK */
 
     /* Enable PLL */
     RCC->CR |= RCC_CR_PLLON;
@@ -1081,20 +534,68 @@
     
     /* Select PLL as system clock source */
     RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
-    RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;    
+    RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;
 
     /* Wait till PLL is used as system clock source */
-    while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)0x08)
+    while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_PLL)
     {
     }
+
+    return 1; // OK
   }
   else
-  { /* If HSE fails to start-up, the application will have wrong clock 
-         configuration. User can add here some code to deal with this error */
+  {
+    return 0; // FAIL
   }
 }
 #endif
 
+/******************************************************************************/
+/*            PLL (clocked by HSI) used as System clock source                */
+/******************************************************************************/
+uint8_t SetSysClock_PLL_HSI(void)
+{
+  __IO uint32_t StartUpCounter = 0;
+  
+  /* Enable Prefetch Buffer */
+  FLASH->ACR |= FLASH_ACR_PRFTBE;
+
+  /* Flash wait states
+     0WS for 0  < SYSCLK <= 24 MHz
+     1WS for 24 < SYSCLK <= 48 MHz
+     2WS for 48 < SYSCLK <= 72 MHz */
+  FLASH->ACR &= (uint32_t)((uint32_t)~FLASH_ACR_LATENCY);
+  FLASH->ACR |= (uint32_t)FLASH_ACR_LATENCY_2;    
+
+  /* PLL configuration
+     PLLCLK = 64 MHz (HSI/2 * 16) */
+  RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL));
+  RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSI_Div2 | RCC_CFGR_PLLMULL16
+                        | RCC_CFGR_HPRE_DIV1    /* HCLK   = 64 MHz */
+                        | RCC_CFGR_PPRE2_DIV1   /* PCLK2  = 64 MHz */
+                        | RCC_CFGR_PPRE1_DIV2); /* PCLK1  = 32 MHz */    
+                                                /* USBCLK = 42.667 MHz (64 MHz / 1.5) --> USB NOT POSSIBLE */
+
+  /* Enable PLL */
+  RCC->CR |= RCC_CR_PLLON;
+
+  /* Wait till PLL is ready */
+  while((RCC->CR & RCC_CR_PLLRDY) == 0)
+  {
+  }
+
+  /* Select PLL as system clock source */
+  RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
+  RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;
+
+  /* Wait till PLL is used as system clock source */
+  while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_PLL)
+  {
+  }
+
+  return 1; // OK
+}
+
 /**
   * @}
   */
@@ -1102,8 +603,9 @@
 /**
   * @}
   */
-  
+
 /**
   * @}
-  */    
+  */
+
 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/