File content as of revision 173:e131a1973e81:

/* mbed Microcontroller Library
* Copyright (c) 2006-2017 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* 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.
*/

/**
  * This file configures the system clock as follows:
  *-----------------------------------------------------------------------------
  * System clock source                | 1- PLL_HSE_EXTC        | 3- PLL_HSI
  *                                    | (external 8 MHz clock) | (internal 16 MHz)
  *                                    | 2- PLL_HSE_XTAL        |
  *                                    | (external 8 MHz xtal)  |
  *-----------------------------------------------------------------------------
  * SYSCLK(MHz)                        | 100                    | 100
  *-----------------------------------------------------------------------------
  * AHBCLK (MHz)                       | 100                    | 100
  *-----------------------------------------------------------------------------
  * APB1CLK (MHz)                      | 50                     | 50
  *-----------------------------------------------------------------------------
  * APB2CLK (MHz)                      | 100                    | 100
  *-----------------------------------------------------------------------------
  * USB capable (48 MHz precise clock) | NO                     | NO
  *-----------------------------------------------------------------------------
**/

#include "stm32f4xx.h"

/*!< Uncomment the following line if you need to relocate your vector Table in
     Internal SRAM. */
/* #define VECT_TAB_SRAM */
#ifndef VECT_TAB_OFFSET
#define VECT_TAB_OFFSET  0x00 /*!< Vector Table base offset field.
                                   This value must be a multiple of 0x200. */
#endif


/* Select the clock sources (other than HSI) to start with (0=OFF, 1=ON) */
#define USE_PLL_HSE_EXTC (0) /* Use external clock */
#define USE_PLL_HSE_XTAL (1) /* Use external xtal */

#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);

/**
  * @brief  Setup the microcontroller system
  *         Initialize the FPU setting, vector table location and External memory
  *         configuration.
  * @param  None
  * @retval None
  */
void SystemInit(void)
{
    /* FPU settings ------------------------------------------------------------*/
#if (__FPU_PRESENT == 1) && (__FPU_USED == 1)
    SCB->CPACR |= ((3UL << 10*2)|(3UL << 11*2));  /* set CP10 and CP11 Full Access */
#endif
    /* Reset the RCC clock configuration to the default reset state ------------*/
    /* Set HSION bit */
    RCC->CR |= (uint32_t)0x00000001;

    /* Reset CFGR register */
    RCC->CFGR = 0x00000000;

    /* Reset HSEON, CSSON and PLLON bits */
    RCC->CR &= (uint32_t)0xFEF6FFFF;

    /* Reset PLLCFGR register */
    RCC->PLLCFGR = 0x24003010;

    /* Reset HSEBYP bit */
    RCC->CR &= (uint32_t)0xFFFBFFFF;

    /* Disable all interrupts */
    RCC->CIR = 0x00000000;

#if defined (DATA_IN_ExtSRAM) || defined (DATA_IN_ExtSDRAM)
    SystemInit_ExtMemCtl();
#endif /* DATA_IN_ExtSRAM || DATA_IN_ExtSDRAM */

    /* Configure the Vector Table location add offset address ------------------*/
#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  Configures the System clock source, PLL Multiplier and Divider factors,
  *               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
  */
void SetSysClock(void)
{
    /* 1- Try to start with HSE and external clock */
#if USE_PLL_HSE_EXTC != 0
    if (SetSysClock_PLL_HSE(1) == 0)
#endif
    {
        /* 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 clock on MCO2 pin(PC9) for debugging purpose */
    //HAL_RCC_MCOConfig(RCC_MCO2, RCC_MCO2SOURCE_SYSCLK, RCC_MCODIV_4); // 100 MHz / 4 = 25 MHz
}

#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)
{
    RCC_ClkInitTypeDef RCC_ClkInitStruct;
    RCC_OscInitTypeDef RCC_OscInitStruct;

    /* The voltage scaling allows optimizing the power consumption when the device is
       clocked below the maximum system frequency, to update the voltage scaling value
       regarding system frequency refer to product datasheet. */
    __HAL_RCC_PWR_CLK_ENABLE();
    __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);

    /* Enable HSE oscillator and activate PLL with HSE as source */
    RCC_OscInitStruct.OscillatorType      = RCC_OSCILLATORTYPE_HSE;
    if (bypass == 0) {
        RCC_OscInitStruct.HSEState          = RCC_HSE_ON; /* External 8 MHz xtal on OSC_IN/OSC_OUT */
    } else {
        RCC_OscInitStruct.HSEState          = RCC_HSE_BYPASS; /* External 8 MHz clock on OSC_IN */
    }
    RCC_OscInitStruct.PLL.PLLState        = RCC_PLL_ON;
    RCC_OscInitStruct.PLL.PLLSource       = RCC_PLLSOURCE_HSE;
    //RCC_OscInitStruct.PLL.PLLM          = 8;             // VCO input clock = 1 MHz (8 MHz / 8)
    //RCC_OscInitStruct.PLL.PLLN          = 400;           // VCO output clock = 400 MHz (1 MHz * 400)
    RCC_OscInitStruct.PLL.PLLM            = 13;             // VCO input clock = 2 MHz (8 MHz / 4)
    RCC_OscInitStruct.PLL.PLLN            = 192;           // VCO output clock = 400 MHz (2 MHz * 200)
    RCC_OscInitStruct.PLL.PLLP            = RCC_PLLP_DIV4; // PLLCLK = 100 MHz (400 MHz / 4)
    RCC_OscInitStruct.PLL.PLLQ            = 8;             // USB clock = 44.44 MHz (400 MHz / 9) --> Not good for USB
    if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
        return 0; // FAIL
    }

    /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks dividers */
    RCC_ClkInitStruct.ClockType      = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
    RCC_ClkInitStruct.SYSCLKSource   = RCC_SYSCLKSOURCE_PLLCLK; // 100 MHz
    RCC_ClkInitStruct.AHBCLKDivider  = RCC_SYSCLK_DIV1;         // 100 MHz
    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;           //  50 MHz
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;           // 100 MHz
    if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_3) != HAL_OK) {
        return 0; // FAIL
    }

    /* Output clock on MCO1 pin(PA8) for debugging purpose */

    //if (bypass == 0)
    //  HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_HSE, RCC_MCODIV_2); // 4 MHz with xtal
    //else
    //  HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_HSE, RCC_MCODIV_1); // 8 MHz with external clock

    return 1; // OK
}
#endif

/******************************************************************************/
/*            PLL (clocked by HSI) used as System clock source                */
/******************************************************************************/
uint8_t SetSysClock_PLL_HSI(void)
{
    RCC_ClkInitTypeDef RCC_ClkInitStruct;
    RCC_OscInitTypeDef RCC_OscInitStruct;

    /* The voltage scaling allows optimizing the power consumption when the device is
       clocked below the maximum system frequency, to update the voltage scaling value
       regarding system frequency refer to product datasheet. */
    __HAL_RCC_PWR_CLK_ENABLE();
    __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);

    /* Enable HSI oscillator and activate PLL with HSI as source */
    RCC_OscInitStruct.OscillatorType      = RCC_OSCILLATORTYPE_HSI | RCC_OSCILLATORTYPE_HSE;
    RCC_OscInitStruct.HSIState            = RCC_HSI_ON;
    RCC_OscInitStruct.HSEState            = RCC_HSE_OFF;
    RCC_OscInitStruct.HSICalibrationValue = 16;
    RCC_OscInitStruct.PLL.PLLState        = RCC_PLL_ON;
    RCC_OscInitStruct.PLL.PLLSource       = RCC_PLLSOURCE_HSI;
    //RCC_OscInitStruct.PLL.PLLM          = 16;            // VCO input clock = 1 MHz (16 MHz / 16)
    //RCC_OscInitStruct.PLL.PLLN          = 400;           // VCO output clock = 400 MHz (1 MHz * 400)
    RCC_OscInitStruct.PLL.PLLM            = 8;             // VCO input clock = 2 MHz (16 MHz / 8)
    RCC_OscInitStruct.PLL.PLLN            = 200;           // VCO output clock = 400 MHz (2 MHz * 200)
    RCC_OscInitStruct.PLL.PLLP            = RCC_PLLP_DIV4; // PLLCLK = 100 MHz (400 MHz / 4)
    RCC_OscInitStruct.PLL.PLLQ            = 9;             // USB clock = 44.44 MHz (400 MHz / 9) --> Not good for USB
    if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
        return 0; // FAIL
    }

    /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks dividers */
    RCC_ClkInitStruct.ClockType      = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
    RCC_ClkInitStruct.SYSCLKSource   = RCC_SYSCLKSOURCE_PLLCLK; // 100 MHz
    RCC_ClkInitStruct.AHBCLKDivider  = RCC_SYSCLK_DIV1;         // 100 MHz
    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;           //  50 MHz
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;           // 100 MHz
    if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_3) != HAL_OK) {
        return 0; // FAIL
    }

    /* Output clock on MCO1 pin(PA8) for debugging purpose */
    //HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_HSI, RCC_MCODIV_1); // 16 MHz

    return 1; // OK
}

/******************************************************************************/
/*            Hard Fault Handler                                              */
/******************************************************************************/
void HardFault_Handler(void)
{
#if !defined(NDEBUG) || NDEBUG == 0
    printf("Hard Fault\n");
#endif
    NVIC_SystemReset();
}