text: /* 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- USE_PLL_HSE_EXTC (external 8 MHz clock)
    *                     | 2- USE_PLL_HSE_XTAL (external 8 MHz xtal)
    *                     | 3- USE_PLL_HSI (internal 16 MHz)
    *                     | 4- USE_PLL_MSI (internal 100kHz to 48 MHz)
    *-----------------------------------------------------------------------------
    * SYSCLK(MHz)         | 80
    * AHBCLK (MHz)        | 80
    * APB1CLK (MHz)       | 80
    * APB2CLK (MHz)       | 80
    * USB capable         | YES
    *-----------------------------------------------------------------------------
  **/
  
  #include "stm32l4xx.h"
  #include "nvic_addr.h"
  #include "mbed_error.h"
  
  /*!< Uncomment the following line if you need to relocate your vector Table in
       Internal SRAM. */
  /* #define VECT_TAB_SRAM */
  #define VECT_TAB_OFFSET  0x00 /*!< Vector Table base offset field.
                                     This value must be a multiple of 0x200. */
  
  
  // clock source is selected with CLOCK_SOURCE in json config
  #define USE_PLL_HSE_EXTC 0x8 // Use external clock (ST Link MCO - not enabled by default)
  #define USE_PLL_HSE_XTAL 0x4 // Use external xtal (X3 on board - not provided by default)
  #define USE_PLL_HSI      0x2 // Use HSI internal clock
  #define USE_PLL_MSI      0x1 // Use MSI internal clock
  
  #define DEBUG_MCO        (0) // Output the MCO on PA8 for debugging (0=OFF, 1=SYSCLK, 2=HSE, 3=HSI, 4=MSI)
  
  #if ( ((CLOCK_SOURCE) & USE_PLL_HSE_XTAL) || ((CLOCK_SOURCE) & USE_PLL_HSE_EXTC) )
  uint8_t SetSysClock_PLL_HSE(uint8_t bypass);
  #endif /* ((CLOCK_SOURCE) & USE_PLL_HSE_XTAL) || ((CLOCK_SOURCE) & USE_PLL_HSE_EXTC) */
  
  #if ((CLOCK_SOURCE) & USE_PLL_HSI)
  uint8_t SetSysClock_PLL_HSI(void);
  #endif /* ((CLOCK_SOURCE) & USE_PLL_HSI) */
  
  #if ((CLOCK_SOURCE) & USE_PLL_MSI)
  uint8_t SetSysClock_PLL_MSI(void);
  #endif /* ((CLOCK_SOURCE) & USE_PLL_MSI) */
  
  
  /**
    * @brief  Setup the microcontroller system.
    * @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 MSION bit */
      RCC->CR |= RCC_CR_MSION;
  
      /* Reset CFGR register */
      RCC->CFGR = 0x00000000;
  
      /* Reset HSEON, CSSON , HSION, and PLLON bits */
      RCC->CR &= (uint32_t)0xEAF6FFFF;
  
      /* Reset PLLCFGR register */
      RCC->PLLCFGR = 0x00001000;
  
      /* Reset HSEBYP bit */
      RCC->CR &= (uint32_t)0xFFFBFFFF;
  
      /* Disable all interrupts */
      RCC->CIER = 0x00000000;
  
      /* 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 = NVIC_FLASH_VECTOR_ADDRESS; /* 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)
  {
  #if ((CLOCK_SOURCE) & USE_PLL_HSE_EXTC)
      /* 1- Try to start with HSE and external clock */
      if (SetSysClock_PLL_HSE(1) == 0)
  #endif
      {
  #if ((CLOCK_SOURCE) & USE_PLL_HSE_XTAL)
          /* 2- If fail try to start with HSE and external xtal */
          if (SetSysClock_PLL_HSE(0) == 0)
  #endif
          {
  #if ((CLOCK_SOURCE) & USE_PLL_HSI)
              /* 3- If fail start with HSI clock */
              if (SetSysClock_PLL_HSI() == 0)
  #endif
              {
  #if ((CLOCK_SOURCE) & USE_PLL_MSI)
                  /* 4- If fail start with MSI clock */
                  if (SetSysClock_PLL_MSI() == 0)
  #endif
                  {
                      {
                          error("SetSysClock failed\n");
                      }
                  }
              }
          }
      }
  
      // Output clock on MCO1 pin(PA8) for debugging purpose
  #if DEBUG_MCO == 1
      HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_SYSCLK, RCC_MCODIV_1);
  #endif
  }
  
  #if ( ((CLOCK_SOURCE) & USE_PLL_HSE_XTAL) || ((CLOCK_SOURCE) & USE_PLL_HSE_EXTC) )
  /******************************************************************************/
  /*            PLL (clocked by HSE) used as System clock source                */
  /******************************************************************************/
  uint8_t SetSysClock_PLL_HSE(uint8_t bypass)
  {
      RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
      RCC_OscInitTypeDef RCC_OscInitStruct = {0};
      RCC_PeriphCLKInitTypeDef RCC_PeriphClkInit = {0};
  
      // Used to gain time after DeepSleep in case HSI is used
      if (__HAL_RCC_GET_FLAG(RCC_FLAG_HSIRDY) != RESET) {
          return 0;
      }
  
      // Select MSI as system clock source to allow modification of the PLL configuration
      RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK;
      RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
      HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0);
  
      // Enable HSE oscillator and activate PLL with HSE as source
      RCC_OscInitStruct.OscillatorType        = RCC_OSCILLATORTYPE_HSE | RCC_OSCILLATORTYPE_HSI;
      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.HSIState              = RCC_HSI_OFF;
      RCC_OscInitStruct.PLL.PLLSource         = RCC_PLLSOURCE_HSE; // 8 MHz
      RCC_OscInitStruct.PLL.PLLState          = RCC_PLL_ON;
      RCC_OscInitStruct.PLL.PLLM              = 1; // VCO input clock = 8 MHz (8 MHz / 1)
      RCC_OscInitStruct.PLL.PLLN              = 20; // VCO output clock = 160 MHz (8 MHz * 20)
      RCC_OscInitStruct.PLL.PLLP              = 7; // PLLSAI3 clock = 22 MHz (160 MHz / 7)
      RCC_OscInitStruct.PLL.PLLQ              = 2;
      RCC_OscInitStruct.PLL.PLLR              = 2; // PLL clock = 80 MHz (160 MHz / 2)
  
      if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
          return 0; // FAIL
      }
  
      // Select PLL clock 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; // 80 MHz
      RCC_ClkInitStruct.AHBCLKDivider  = RCC_SYSCLK_DIV1;         // 80 MHz
      RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;           /* 80 MHz */
      RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;           // 80 MHz
      if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK) {
          return 0; // FAIL
      }
  
      RCC_PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USB;
      RCC_PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_PLLSAI1;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1Source = RCC_PLLSOURCE_HSE;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1M = 1;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1N = 12;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1P = RCC_PLLP_DIV7;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1Q = RCC_PLLQ_DIV2;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1R = RCC_PLLR_DIV2;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1ClockOut = RCC_PLLSAI1_48M2CLK;
      if (HAL_RCCEx_PeriphCLKConfig(&RCC_PeriphClkInit) != HAL_OK) {
          return 0; // FAIL
      }
  
      // Disable MSI Oscillator
      RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
      RCC_OscInitStruct.MSIState       = RCC_MSI_OFF;
      RCC_OscInitStruct.PLL.PLLState   = RCC_PLL_NONE; // No PLL update
      HAL_RCC_OscConfig(&RCC_OscInitStruct);
  
      /* Select HSI as clock source for LPUART1 */
      RCC_PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
      RCC_PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_HSI;
      if (HAL_RCCEx_PeriphCLKConfig(&RCC_PeriphClkInit) != HAL_OK) {
          return 0; // FAIL
      }
  
      // Output clock on MCO1 pin(PA8) for debugging purpose
  #if DEBUG_MCO == 2
      if (bypass == 0) {
          HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_HSE, RCC_MCODIV_2);    // 4 MHz
      } else {
          HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_HSE, RCC_MCODIV_1);    // 8 MHz
      }
  #endif
  
      return 1; // OK
  }
  #endif /* ((CLOCK_SOURCE) & USE_PLL_HSE_XTAL) || ((CLOCK_SOURCE) & USE_PLL_HSE_EXTC) */
  
  #if ((CLOCK_SOURCE) & USE_PLL_HSI)
  /******************************************************************************/
  /*            PLL (clocked by HSI) used as System clock source                */
  /******************************************************************************/
  uint8_t SetSysClock_PLL_HSI(void)
  {
      RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
      RCC_OscInitTypeDef RCC_OscInitStruct = {0};
      RCC_PeriphCLKInitTypeDef RCC_PeriphClkInit = {0};
  
      // Select MSI as system clock source to allow modification of the PLL configuration
      RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK;
      RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
      HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0);
  
      // Enable HSI oscillator and activate PLL with HSI as source
      RCC_OscInitStruct.OscillatorType       = RCC_OSCILLATORTYPE_HSI | RCC_OSCILLATORTYPE_HSE;
      RCC_OscInitStruct.HSEState             = RCC_HSE_OFF;
      RCC_OscInitStruct.HSIState             = RCC_HSI_ON;
      RCC_OscInitStruct.HSICalibrationValue  = RCC_HSICALIBRATION_DEFAULT;
      RCC_OscInitStruct.PLL.PLLState         = RCC_PLL_ON;
      RCC_OscInitStruct.PLL.PLLSource        = RCC_PLLSOURCE_HSI; // 16 MHz
      RCC_OscInitStruct.PLL.PLLM             = 2; // VCO input clock = 8 MHz (16 MHz / 2)
      RCC_OscInitStruct.PLL.PLLN             = 20; // VCO output clock = 160 MHz (8 MHz * 20)
      RCC_OscInitStruct.PLL.PLLP             = 7; // PLLSAI3 clock = 22 MHz (160 MHz / 7)
      RCC_OscInitStruct.PLL.PLLQ             = 2;
      RCC_OscInitStruct.PLL.PLLR             = 2; // PLL clock = 80 MHz (160 MHz / 2)
      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; // 80 MHz
      RCC_ClkInitStruct.AHBCLKDivider  = RCC_SYSCLK_DIV1;         // 80 MHz
      RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;           // 80 MHz
      RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;           // 80 MHz
      if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK) {
          return 0; // FAIL
      }
  
      RCC_PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USB;
      RCC_PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_PLLSAI1;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1Source = RCC_PLLSOURCE_HSI;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1M = 2;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1N = 12;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1P = RCC_PLLP_DIV7;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1Q = RCC_PLLQ_DIV2;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1R = RCC_PLLR_DIV2;
      RCC_PeriphClkInit.PLLSAI1.PLLSAI1ClockOut = RCC_PLLSAI1_48M2CLK;
      if (HAL_RCCEx_PeriphCLKConfig(&RCC_PeriphClkInit) != HAL_OK) {
          return 0; // FAIL
      }
  
      // Disable MSI Oscillator
      RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
      RCC_OscInitStruct.MSIState       = RCC_MSI_OFF;
      RCC_OscInitStruct.PLL.PLLState   = RCC_PLL_NONE; // No PLL update
      HAL_RCC_OscConfig(&RCC_OscInitStruct);
  
      /* Select HSI as clock source for LPUART1 */
      RCC_PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
      RCC_PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_HSI;
      if (HAL_RCCEx_PeriphCLKConfig(&RCC_PeriphClkInit) != HAL_OK) {
          return 0; // FAIL
      }
  
      // Output clock on MCO1 pin(PA8) for debugging purpose
  #if DEBUG_MCO == 3
      HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_HSI, RCC_MCODIV_1); // 16 MHz
  #endif
  
      return 1; // OK
  }
  #endif /* ((CLOCK_SOURCE) & USE_PLL_HSI) */
  
  #if ((CLOCK_SOURCE) & USE_PLL_MSI)
  /******************************************************************************/
  /*            PLL (clocked by MSI) used as System clock source                */
  /******************************************************************************/
  uint8_t SetSysClock_PLL_MSI(void)
  {
      RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
      RCC_OscInitTypeDef RCC_OscInitStruct = {0};
      RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
  
      // Enable LSE Oscillator to automatically calibrate the MSI clock
      RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSE;
      RCC_OscInitStruct.PLL.PLLState   = RCC_PLL_NONE; // No PLL update
      RCC_OscInitStruct.LSEState       = RCC_LSE_ON; // External 32.768 kHz clock on OSC_IN/OSC_OUT
      if (HAL_RCC_OscConfig(&RCC_OscInitStruct) == HAL_OK) {
          RCC->CR |= RCC_CR_MSIPLLEN; // Enable MSI PLL-mode
      }
  
      HAL_RCCEx_DisableLSECSS();
      /* Enable MSI Oscillator and activate PLL with MSI as source */
      RCC_OscInitStruct.OscillatorType      = RCC_OSCILLATORTYPE_MSI | RCC_OSCILLATORTYPE_HSI | RCC_OSCILLATORTYPE_HSE;
      RCC_OscInitStruct.MSIState             = RCC_MSI_ON;
      RCC_OscInitStruct.HSEState             = RCC_HSE_OFF;
      RCC_OscInitStruct.HSIState             = RCC_HSI_OFF;
      RCC_OscInitStruct.MSICalibrationValue = RCC_MSICALIBRATION_DEFAULT;
      RCC_OscInitStruct.MSIClockRange       = RCC_MSIRANGE_11; /* 48 MHz */
      RCC_OscInitStruct.PLL.PLLState        = RCC_PLL_ON;
      RCC_OscInitStruct.PLL.PLLSource       = RCC_PLLSOURCE_MSI;
      RCC_OscInitStruct.PLL.PLLM            = 6;    /* 8 MHz */
      RCC_OscInitStruct.PLL.PLLN            = 40;   /* 320 MHz */
      RCC_OscInitStruct.PLL.PLLP            = 7;    /* 45 MHz */
      RCC_OscInitStruct.PLL.PLLQ            = 4;    /* 80 MHz */
      RCC_OscInitStruct.PLL.PLLR            = 4;    /* 80 MHz */
      if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
          return 0; // FAIL
      }
      /* Enable MSI Auto-calibration through LSE */
      HAL_RCCEx_EnableMSIPLLMode();
      /* Select MSI output as USB clock source */
      PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_USB;
      PeriphClkInitStruct.UsbClockSelection = RCC_USBCLKSOURCE_MSI; /* 48 MHz */
      HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
  
      // 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; /* 80 MHz */
      RCC_ClkInitStruct.AHBCLKDivider  = RCC_SYSCLK_DIV1;         /* 80 MHz */
      RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;           /* 80 MHz */
      RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;           /* 80 MHz */
      if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK) {
          return 0; // FAIL
      }
  
      /* Select LSE as clock source for LPUART1 */
      PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
      PeriphClkInitStruct.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_LSE;
      if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK) {
          return 0; // FAIL
      }
  
      // Output clock on MCO1 pin(PA8) for debugging purpose
  #if DEBUG_MCO == 4
      HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_MSI, RCC_MCODIV_2); // 2 MHz
  #endif
  
      return 1; // OK
  }
  #endif /* ((CLOCK_SOURCE) & USE_PLL_MSI) */
  