/********************************** (C) COPYRIGHT *******************************
 * File Name          : system_ch32x035.c
 * Author             : WCH
 * Version            : V1.0.0
 * Date               : 2023/04/06
 * Description        : CH32X035 Device Peripheral Access Layer System Source File.
*********************************************************************************
* Copyright (c) 2021 Nanjing Qinheng Microelectronics Co., Ltd.
* Attention: This software (modified or not) and binary are used for 
* microcontroller manufactured by Nanjing Qinheng Microelectronics.
*******************************************************************************/
#include "ch32x035.h"
#include "global.h"

/* 
* Uncomment the line corresponding to the desired System clock (SYSCLK) frequency (after 
* reset the HSI is used as SYSCLK source).
*/

/* Clock Definitions */
/*
#ifdef SYSCLK_FREQ_8MHz_HSI
uint32_t SystemCoreClock         = SYSCLK_FREQ_8MHz_HSI;         // System Clock Frequency (Core Clock)
#elif defined SYSCLK_FREQ_12MHz_HSI
uint32_t SystemCoreClock         = SYSCLK_FREQ_12MHz_HSI;        // System Clock Frequency (Core Clock)
#elif defined SYSCLK_FREQ_16MHz_HSI
uint32_t SystemCoreClock         = SYSCLK_FREQ_16MHz_HSI;        // System Clock Frequency (Core Clock)
#elif defined SYSCLK_FREQ_24MHz_HSI
uint32_t SystemCoreClock         = SYSCLK_FREQ_24MHz_HSI;        // System Clock Frequency (Core Clock)
#else
uint32_t SystemCoreClock         = HSI_VALUE;                    // System Clock Frequency (Core Clock)
#endif
*/

uint32_t SystemCoreClock;

__I uint8_t AHBPrescTable[16] = {1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8};


/* system_private_function_proto_types */
void SetSysClock(uint32_t clock);

/*
#ifdef SYSCLK_FREQ_8MHz_HSI
static void SetSysClockTo8_HSI( void );
#elif defined SYSCLK_FREQ_12MHz_HSI
static void SetSysClockTo12_HSI( void );
#elif defined SYSCLK_FREQ_16MHz_HSI
static void SetSysClockTo16_HSI( void );
#elif defined SYSCLK_FREQ_24MHz_HSI
static void SetSysClockTo24_HSI( void );
#elif defined SYSCLK_FREQ_48MHz_HSI
static void SetSysClockTo48_HSI( void );
#endif
*/

static void SetSysClockToX_HSI(uint32_t div, uint32_t latency);


/*********************************************************************
 * @fn      SystemInit
 *
 * @brief   Setup the microcontroller system Initialize the Embedded Flash Interface,
 *        update the SystemCoreClock variable.
 *
 * @return  none
 */
void SystemInit (void)
{
    RCC->CTLR |= (uint32_t)0x00000001;
    RCC->CFGR0 |= (uint32_t)0x00000050;
    RCC->CFGR0 &= (uint32_t)0xF8FFFF5F;
    SetSysClock(SYSCLK_FREQ_NORMAL);
}

/*********************************************************************
 * @fn      SystemCoreClockUpdate
 *
 * @brief   Update SystemCoreClock variable according to Clock Register Values.
 *
 * @return  none
 */
void SystemCoreClockUpdate (void)
{
    uint32_t tmp = 0;

    SystemCoreClock = HSI_VALUE;
    tmp = AHBPrescTable[((RCC->CFGR0 & RCC_HPRE) >> 4)];

    if(((RCC->CFGR0 & RCC_HPRE) >> 4) < 8)
    {
        SystemCoreClock /= tmp;
    }
    else
    {
        SystemCoreClock >>= tmp;
    }
}

/*********************************************************************
 * @fn      SetSysClock
 *
 * @brief   Configures the System clock frequency, HCLK prescalers.
 *
 * @return  none
 */
void SetSysClock(uint32_t clock)
{
    switch (clock) {
        case SYSCLK_FREQ_48MHz_HSI: { SetSysClockToX_HSI(RCC_HPRE_DIV1, FLASH_ACTLR_LATENCY_2); break; }
        case SYSCLK_FREQ_24MHz_HSI: { SetSysClockToX_HSI(RCC_HPRE_DIV2, FLASH_ACTLR_LATENCY_1); break; }
        case SYSCLK_FREQ_16MHz_HSI: { SetSysClockToX_HSI(RCC_HPRE_DIV3, FLASH_ACTLR_LATENCY_1); break; }
        case SYSCLK_FREQ_12MHz_HSI: { SetSysClockToX_HSI(RCC_HPRE_DIV4, FLASH_ACTLR_LATENCY_0); break; }
        default: {
            SetSysClockToX_HSI(RCC_HPRE_DIV6, FLASH_ACTLR_LATENCY_0);
            clock = 8000000;
            break;
        }
    }

    SystemCoreClock = clock;

    /*
#ifdef SYSCLK_FREQ_8MHz_HSI
    SetSysClockTo8_HSI();
#elif defined SYSCLK_FREQ_12MHz_HSI
    SetSysClockTo12_HSI();
#elif defined SYSCLK_FREQ_16MHz_HSI
    SetSysClockTo16_HSI();
#elif defined SYSCLK_FREQ_24MHz_HSI
    SetSysClockTo24_HSI();
#elif defined SYSCLK_FREQ_48MHz_HSI
    SetSysClockTo48_HSI();
#endif
    */
}


static void SetSysClockToX_HSI(uint32_t div, uint32_t latency)
{
    uint32_t actlr;
    uint32_t cfgr0;

    /* Flash 2 wait state */
    actlr = FLASH->ACTLR &= (uint32_t)((uint32_t)~FLASH_ACTLR_LATENCY);
    FLASH->ACTLR = (uint32_t)actlr | FLASH_ACTLR_LATENCY_2;

    /* HCLK = SYSCLK = APB1 */
    cfgr0 = RCC->CFGR0 &= (uint32_t)0xFFFFFF0F;
    RCC->CFGR0 = (uint32_t)cfgr0 | (div & 0xf0);

    /* Flash set wait state */
    FLASH->ACTLR = (uint32_t)actlr | (latency & 0x03);
}