therm Changeset - 3e00cf5fc57d · protofusion repositories

Changeset - 3e00cf5fc57d

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2 1 2

Ethan Zonca - 10 years ago 2014-07-11 17:44:35
ez@ethanzonca.com

Trying to make clocks work

3 files changed with 8 insertions and 7 deletions:

main.c

system_stm32l1xx.h

rename

system_stm32l1xx_4meg_extxtal.c

0 comments (0 inline, 0 general)

main.c

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 #include "main.h"
 #include "stm32l100c_discovery.h"
 #include "ssd1306.h"
 #define LED_POWER GPIOB,GPIO_Pin_9
 #define LED_STAT  GPIOA,GPIO_Pin_15
 static __IO uint32_t TimingDelay;
 void init_gpio();
 void init_spi();
 int main(void)
+{
     // Init clocks
     SystemInit();
     RCC_ClocksTypeDef RCC_Clocks;
     // SysTick end of count event each 1ms
     RCC_GetClocksFreq(&RCC_Clocks);
     SysTick_Config(RCC_Clocks.HCLK_Frequency / 1000);
     GPIO_ResetBits(LED_STAT);
     Delay(100);
     init_gpio();
     init_spi();
     //ssd1306_Init();
     //SSD1303_DrawPoint(3,3,1);
     //SSD1303_DrawPoint(5,5,0);
     ssd1306_Init();
     ssd1306_DrawPoint(3,3,1);
     ssd1306_DrawPoint(5,5,0);
     GPIO_SetBits(LED_POWER);
     Delay(500);
     GPIO_ResetBits(LED_POWER);
     while(1)
+    {
         ssd1306_DrawPoint(5,5,0);
         GPIO_SetBits(LED_POWER);
         Delay(150);
         GPIO_ResetBits(LED_POWER);
         Delay(150);
+    }
+}
 /**
   * @brief  Inserts a delay time.
   * @param  nTime: specifies the delay time length, in 1 ms.
   * @retval None
   */
 void Delay(__IO uint32_t nTime)
+{
   TimingDelay = nTime;
   while(TimingDelay != 0);
+}
 /**
   * @brief  Decrements the TimingDelay variable.
   * @param  None
   * @retval None
   */
 void TimingDelay_Decrement(void)
+{
   if (TimingDelay != 0x00)
+  {
     TimingDelay--;
+  }
+}
 void init_spi(void)
+{
     SPI_InitTypeDef  SPI_InitStructure;
     // OLED IC
     SPI_InitStructure.SPI_Direction = SPI_Direction_1Line_Tx;
     SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
     SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
     SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;
     SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
     SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
     SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_64;
     SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
     SPI_InitStructure.SPI_CRCPolynomial = 7;
     SPI_Init(SPI1, &SPI_InitStructure);
     SPI_Cmd(SPI1, ENABLE);           /* Enable the SPI  */
     // MAX IC
     SPI_InitStructure.SPI_Direction = SPI_Direction_1Line_Rx;
     SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
     SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
     SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;
     SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
     SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
     SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_64;
     SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
     SPI_InitStructure.SPI_CRCPolynomial = 7;
     SPI_Init(SPI2, &SPI_InitStructure);
     SPI_Cmd(SPI2, ENABLE);           /* Enable the SPI */
+}
 void init_gpio(void) {
  GPIO_InitTypeDef GPIO_InitStruct;
   // Enable SPI clocks
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
   RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);
   // Enable GPIO clocks
   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOC|RCC_AHBPeriph_GPIOB|RCC_AHBPeriph_GPIOA, ENABLE);
   // Enable DMA clocks (Is AHB even the right thing???)
   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); // EMZ TODO get the right ones
   /*Configure GPIO pin : PC */
   GPIO_InitStruct.GPIO_Pin = GPIO_Pin_13;
   GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
   GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
   GPIO_InitStruct.GPIO_Speed = GPIO_Speed_400KHz;
   GPIO_Init(GPIOC, &GPIO_InitStruct);
   /*Configure GPIO pin : PB */
   GPIO_InitStruct.GPIO_Pin = GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_10|GPIO_Pin_12
                           |GPIO_Pin_9;
   GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
   GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
   GPIO_InitStruct.GPIO_Speed = GPIO_Speed_400KHz;
   GPIO_Init(GPIOB, &GPIO_InitStruct);
   /*Configure GPIO pin : PA */
   GPIO_InitStruct.GPIO_Pin = GPIO_Pin_15;
   GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
   GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
   GPIO_InitStruct.GPIO_Speed = GPIO_Speed_400KHz;
   GPIO_Init(GPIOA, &GPIO_InitStruct);
   /*Configure GPIO pin : PB */
   GPIO_InitStruct.GPIO_Pin = GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6
                           |GPIO_Pin_7;
   GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN;
   GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
   GPIO_Init(GPIOB, &GPIO_InitStruct);
   /** SPI1 GPIO Configuration
   PA5   ------> SPI1_SCK
   PA7   ------> SPI1_MOSI
   */
   /*Enable or disable the AHB peripheral clock */
   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
   /*Configure GPIO pin : PA */
   GPIO_InitStruct.GPIO_Pin = GPIO_Pin_5|GPIO_Pin_7;
   GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
   GPIO_InitStruct.GPIO_Speed = GPIO_Speed_400KHz;
   GPIO_Init(GPIOA, &GPIO_InitStruct);
   /*Configure GPIO pin alternate function */
   GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
   /*Configure GPIO pin alternate function */
   GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);
   /** SPI2 GPIO Configuration
   PB13   ------> SPI2_SCK
   PB14   ------> SPI2_MISO
   PB15   ------> SPI2_MOSI
   */
   /*Enable or disable the AHB peripheral clock */
   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);
   /*Configure GPIO pin : PB */
   GPIO_InitStruct.GPIO_Pin = GPIO_Pin_13|GPIO_Pin_14|GPIO_Pin_15;
   GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
   GPIO_InitStruct.GPIO_Speed = GPIO_Speed_400KHz;
   GPIO_Init(GPIOB, &GPIO_InitStruct);
   /*Configure GPIO pin alternate function */
   GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_SPI2);
   /*Configure GPIO pin alternate function */
   GPIO_PinAFConfig(GPIOB, GPIO_PinSource14, GPIO_AF_SPI2);
   /*Configure GPIO pin alternate function */
   GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_SPI2);
   /** USB GPIO Configuration
   PA11   ------> USB_DM
   PA12   ------> USB_DP
   */
   /*Enable or disable the AHB peripheral clock */
   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
   /*Configure GPIO pin : PA */
   GPIO_InitStruct.GPIO_Pin = GPIO_Pin_11|GPIO_Pin_12;
   GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
   GPIO_InitStruct.GPIO_Speed = GPIO_Speed_400KHz;
   GPIO_Init(GPIOA, &GPIO_InitStruct);
+}
 #ifdef  USE_FULL_ASSERT
 /**
   * @brief  Reports the name of the source file and the source line number
   *   where the assert_param error has occurred.
   * @param  file: pointer to the source file name
   * @param  line: assert_param error line source number
   * @retval None
   */
 void assert_failed(uint8_t* file, uint32_t line)
+{
   /* User can add his own implementation to report the file name and line number,
      ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
   /* Infinite loop */
   while (1)
   {}
+}
 #endif
 // vim:softtabstop=4 shiftwidth=4 expandtab

system_stm32l1xx.h

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file renamed from libraries/CMSIS/Device/ST/STM32L1xx/Include/system_stm32l1xx.h to system_stm32l1xx.h

system_stm32l1xx_4meg_extxtal.c

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@@ file renamed from system_stm32l1xx.c to system_stm32l1xx_4meg_extxtal.c @@
 /**
   ******************************************************************************
   * @file    system_stm32l1xx.c
   * @author  MCD Application Team
   * @version V1.2.0
-  * @date    10-July-2014
+  * @date    11-July-2014
   * @brief   CMSIS Cortex-M3 Device Peripheral Access Layer System Source File.
   *          This file contains the system clock configuration for STM32L1xx Ultra
   *          Low power devices, and is generated by the clock configuration
   *          tool  STM32L1xx_Clock_Configuration_V1.2.0.xls
+  *
   * 1.  This file provides two functions and one global variable to be called from
   *     user application:
   *      - SystemInit(): Setups the system clock (System clock source, PLL Multiplier
   *                      and Divider factors, AHB/APBx prescalers and Flash settings),
   *                      depending on the configuration made in the clock xls tool.
   *                      This function is called at startup just after reset and
   *                      before branch to main program. This call is made inside
   *                      the "startup_stm32l1xx_xx.s" file.
+  *
   *      - SystemCoreClock variable: Contains the core clock (HCLK), it can be used
   *                                  by the user application to setup the SysTick
   *                                  timer or configure other parameters.
+  *
   *      - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must
   *                                 be called whenever the core clock is changed
   *                                 during program execution.
+  *
   * 2. After each device reset the MSI (2.1 MHz Range) is used as system clock source.
   *    Then SystemInit() function is called, in "startup_stm32l1xx_xx.s" file, to
   *    configure the system clock before to branch to main program.
+  *
   * 3. If the system clock source selected by user fails to startup, the SystemInit()
   *    function will do nothing and MSI still used as system clock source. User can
   *    add some code to deal with this issue inside the SetSysClock() function.
+  *
   * 4. The default value of HSE crystal is set to 8MHz, refer to "HSE_VALUE" define
   *    in "stm32l1xx.h" file. 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 Configuration
   *=============================================================================
   *        System Clock source          | PLL(HSE)
   *-----------------------------------------------------------------------------
   *        SYSCLK                       | 32000000 Hz
   *-----------------------------------------------------------------------------
   *        HCLK                         | 32000000 Hz
   *-----------------------------------------------------------------------------
   *        AHB Prescaler                | 1
   *-----------------------------------------------------------------------------
   *        APB1 Prescaler               | 1
   *-----------------------------------------------------------------------------
   *        APB2 Prescaler               | 1
   *-----------------------------------------------------------------------------
-  *        HSE Frequency                | 8000000 Hz
+  *        HSE Frequency                | 4000000 Hz
   *-----------------------------------------------------------------------------
   *        PLL DIV                      | 3
   *-----------------------------------------------------------------------------
-  *        PLL MUL                      | 12
+  *        PLL MUL                      | 24
   *-----------------------------------------------------------------------------
   *        VDD                          | 3.3 V
   *-----------------------------------------------------------------------------
   *        Vcore                        | 1.8 V (Range 1)
   *-----------------------------------------------------------------------------
   *        Flash Latency                | 1 WS
   *-----------------------------------------------------------------------------
   *        Require 48MHz for USB clock  | Enabled
   *-----------------------------------------------------------------------------
   *=============================================================================
   * @attention
+  *
   * <h2><center>&copy; COPYRIGHT 2013 STMicroelectronics</center></h2>
+  *
   * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
   * You may not use this file except in compliance with the License.
   * You may obtain a copy of the License at:
+  *
   *        http://www.st.com/software_license_agreement_liberty_v2
+  *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
+  *
   ******************************************************************************
   */
 /** @addtogroup CMSIS
   * @{
   */
 /** @addtogroup stm32l1xx_system
   * @{
   */
 /** @addtogroup STM32L1xx_System_Private_Includes
   * @{
   */
 #include "stm32l1xx.h"
 /**
   * @}
   */
 /** @addtogroup STM32L1xx_System_Private_TypesDefinitions
   * @{
   */
 /**
   * @}
   */
 /** @addtogroup STM32L1xx_System_Private_Defines
   * @{
   */
 /*!< 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. */
 /**
   * @}
   */
 /** @addtogroup STM32L1xx_System_Private_Macros
   * @{
   */
 /**
   * @}
   */
 /** @addtogroup STM32L1xx_System_Private_Variables
   * @{
   */
 uint32_t SystemCoreClock    = 32000000;
 __I uint8_t PLLMulTable[9] = {3, 4, 6, 8, 12, 16, 24, 32, 48};
 __I uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
 /**
   * @}
   */
 /** @addtogroup STM32L1xx_System_Private_FunctionPrototypes
   * @{
   */
 static void SetSysClock(void);
 /**
   * @}
   */
 /** @addtogroup STM32L1xx_System_Private_Functions
   * @{
   */
 /**
   * @brief  Setup the microcontroller system.
   *         Initialize the Embedded Flash Interface, the PLL and update the
   *         SystemCoreClock variable.
   * @param  None
   * @retval None
   */
 void SystemInit (void)
+{
   /*!< Set MSION bit */
   RCC->CR |= (uint32_t)0x00000100;
   /*!< Reset SW[1:0], HPRE[3:0], PPRE1[2:0], PPRE2[2:0], MCOSEL[2:0] and MCOPRE[2:0] bits */
   RCC->CFGR &= (uint32_t)0x88FFC00C;
   /*!< Reset HSION, HSEON, CSSON and PLLON bits */
   RCC->CR &= (uint32_t)0xEEFEFFFE;
   /*!< Reset HSEBYP bit */
   RCC->CR &= (uint32_t)0xFFFBFFFF;
   /*!< Reset PLLSRC, PLLMUL[3:0] and PLLDIV[1:0] bits */
   RCC->CFGR &= (uint32_t)0xFF02FFFF;
   /*!< Disable all interrupts */
   RCC->CIR = 0x00000000;
   /* Configure the System clock frequency, AHB/APBx prescalers and Flash settings */
   SetSysClock();
 #ifdef VECT_TAB_SRAM
   SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM. */
 #else
   SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH. */
 #endif
+}
 /**
   * @brief  Update SystemCoreClock according to Clock Register Values
   *         The SystemCoreClock variable contains the core clock (HCLK), it can
   *         be used by the user application to setup the SysTick timer or configure
   *         other parameters.
+  *
   * @note   Each time the core clock (HCLK) changes, this function must be called
   *         to update SystemCoreClock variable value. Otherwise, any configuration
   *         based on this variable will be incorrect.
+  *
   * @note   - The system frequency computed by this function is not the real
   *           frequency in the chip. It is calculated based on the predefined
   *           constant and the selected clock source:
+  *
   *           - If SYSCLK source is MSI, SystemCoreClock will contain the MSI
   *             value as defined by the MSI range.
+  *
   *           - If SYSCLK source is HSI, SystemCoreClock will contain the HSI_VALUE(*)
+  *
   *           - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(**)
+  *
   *           - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(**)
   *             or HSI_VALUE(*) multiplied/divided by the PLL factors.
+  *
   *         (*) HSI_VALUE is a constant defined in stm32l1xx.h file (default value
   *             16 MHz) but the real value may vary depending on the variations
   *             in voltage and temperature.
+  *
   *         (**) HSE_VALUE is a constant defined in stm32l1xx.h file (default value
   *              8 MHz), user has to ensure that HSE_VALUE is same as the real
   *              frequency of the crystal used. Otherwise, this function may
   *              have wrong result.
+  *
   *         - The result of this function could be not correct when using fractional
   *           value for HSE crystal.
   * @param  None
   * @retval None
   */
 void SystemCoreClockUpdate (void)
+{
   uint32_t tmp = 0, pllmul = 0, plldiv = 0, pllsource = 0, msirange = 0;
   /* Get SYSCLK source -------------------------------------------------------*/
   tmp = RCC->CFGR & RCC_CFGR_SWS;
   switch (tmp)
+  {
     case 0x00:  /* MSI used as system clock */
       msirange = (RCC->ICSCR & RCC_ICSCR_MSIRANGE) >> 13;
       SystemCoreClock = (32768 * (1 << (msirange + 1)));
       break;
     case 0x04:  /* HSI used as system clock */
       SystemCoreClock = HSI_VALUE;
       break;
     case 0x08:  /* HSE used as system clock */
       SystemCoreClock = HSE_VALUE;
       break;
     case 0x0C:  /* PLL used as system clock */
       /* Get PLL clock source and multiplication factor ----------------------*/
       pllmul = RCC->CFGR & RCC_CFGR_PLLMUL;
       plldiv = RCC->CFGR & RCC_CFGR_PLLDIV;
       pllmul = PLLMulTable[(pllmul >> 18)];
       plldiv = (plldiv >> 22) + 1;
       pllsource = RCC->CFGR & RCC_CFGR_PLLSRC;
       if (pllsource == 0x00)
+      {
         /* HSI oscillator clock selected as PLL clock entry */
         SystemCoreClock = (((HSI_VALUE) * pllmul) / plldiv);
+      }
       else
+      {
         /* HSE selected as PLL clock entry */
         SystemCoreClock = (((HSE_VALUE) * pllmul) / plldiv);
+      }
       break;
     default: /* MSI used as system clock */
       msirange = (RCC->ICSCR & RCC_ICSCR_MSIRANGE) >> 13;
       SystemCoreClock = (32768 * (1 << (msirange + 1)));
       break;
+  }
   /* Compute HCLK clock frequency --------------------------------------------*/
   /* Get HCLK prescaler */
   tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)];
   /* HCLK clock frequency */
   SystemCoreClock >>= tmp;
+}
 /**
   * @brief  Configures the System clock frequency, AHB/APBx prescalers and Flash
   *         settings.
   * @note   This function should be called only once the RCC clock configuration
   *         is reset to the default reset state (done in SystemInit() function).
   * @param  None
   * @retval None
   */
 static void SetSysClock(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 64-bit access */
     FLASH->ACR |= FLASH_ACR_ACC64;
     /* Enable Prefetch Buffer */
     FLASH->ACR |= FLASH_ACR_PRFTEN;
     /* Flash 1 wait state */
     FLASH->ACR |= FLASH_ACR_LATENCY;
     /* Power enable */
     RCC->APB1ENR |= RCC_APB1ENR_PWREN;
     /* Select the Voltage Range 1 (1.8 V) */
     PWR->CR = PWR_CR_VOS_0;
     /* Wait Until the Voltage Regulator is ready */
     while((PWR->CSR & PWR_CSR_VOSF) != RESET)
+    {
+    }
     /* HCLK = SYSCLK /1*/
     RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
     /* PCLK2 = HCLK /1*/
     RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
     /* PCLK1 = HCLK /1*/
     RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV1;
     /*  PLL configuration */
     RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLMUL |
                                         RCC_CFGR_PLLDIV));
-    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMUL12 | RCC_CFGR_PLLDIV3);
+    RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMUL24 | RCC_CFGR_PLLDIV3);
     /* 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)
+    {
+    }
+  }
   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 */
+  }
+}
 /**
   * @}
   */
 /**
   * @}
   */
 /**
   * @}
   */
 /******************* (C) COPYRIGHT 2013 STMicroelectronics *****END OF FILE****/

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