RCC: Max frequency with HSI16

The following code set the microcontroller main bus clock up to 64MHz using the internal oscillator. This code can be placed in this function or somewhere else,

#include "bsp.h"

int main( void )
{
    HAL_Init();     /*Init HAL library and call the HAL_MspInit function*/
    
    while(1)
    {
    }
}

msps.c

void Msp_Init( void )
{
    RCC_OscInitTypeDef RCC_OscInitStruct = {0};
    RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

    __HAL_RCC_SYSCFG_CLK_ENABLE();
    __HAL_RCC_PWR_CLK_ENABLE();

    /*Configure the main internal regulator output voltage*/
    HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1);

    /* Initializes the RCC Oscillators according to the specified parameters in the RCC_OscInitTypeDef structure
    The frequency set is 64MHz with the internal 16MHz HSI oscilator. According to the formulas:
      fVCO = fPLLIN x ( N / M ) = 16MHz x (8 / 1) = 128MHz
      fPLLP = fVCO / P = 128MHz / 2 = 64MHz
      fPLLQ = fVCO / Q = 128MHz / 2 = 64MHz
      fPLLR = fVCO / R = 128MHz / 2 = 64MHz
    */
    RCC_OscInitStruct.OscillatorType      = RCC_OSCILLATORTYPE_HSI;
    RCC_OscInitStruct.HSIState            = RCC_HSI_ON;  /*enable HSI oscillator*/
    RCC_OscInitStruct.HSIDiv              = RCC_HSI_DIV1;
    RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
    RCC_OscInitStruct.PLL.PLLState        = RCC_PLL_ON;
    RCC_OscInitStruct.PLL.PLLSource       = RCC_PLLSOURCE_HSI;
    RCC_OscInitStruct.PLL.PLLM            = RCC_PLLM_DIV1;
    RCC_OscInitStruct.PLL.PLLN            = 8;
    RCC_OscInitStruct.PLL.PLLP            = RCC_PLLP_DIV2;
    RCC_OscInitStruct.PLL.PLLQ            = RCC_PLLQ_DIV2;
    RCC_OscInitStruct.PLL.PLLR            = RCC_PLLR_DIV2;
    HAL_RCC_OscConfig( &RCC_OscInitStruct );
  
    /*Initializes the CPU, AHB and APB buses clocks*/
    RCC_ClkInitStruct.ClockType       = RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_PCLK1;
    RCC_ClkInitStruct.SYSCLKSource    = RCC_SYSCLKSOURCE_PLLCLK;
    RCC_ClkInitStruct.AHBCLKDivider   = RCC_SYSCLK_DIV1;    /*no divider for AHB bus fAHB = 64MHz*/
    RCC_ClkInitStruct.APB1CLKDivider  = RCC_HCLK_DIV1;      /*no divider for APB bus fAPB = 64MHz*/
    HAL_RCC_ClockConfig( &RCC_ClkInitStruct, FLASH_LATENCY_2 );
}