/******************************************************************************************************************************************
* 文件名称:	system_SWM320.c
* 功能说明:	SWM320单片机的时钟设置
* 技术支持:	http://www.synwit.com.cn/e/tool/gbook/?bid=1
* 注意事项:
* 版本日期: V1.1.0		2017年10月25日
* 升级记录:
*
*
*******************************************************************************************************************************************
* @attention
*
* THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS WITH CODING INFORMATION
* REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME. AS A RESULT, SYNWIT SHALL NOT BE HELD LIABLE
* FOR ANY DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE CONTENT
* OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING INFORMATION CONTAINED HEREIN IN CONN-
* -ECTION WITH THEIR PRODUCTS.
*
* COPYRIGHT 2012 Synwit Technology
*******************************************************************************************************************************************/
#include <stdint.h>
#include "SWM320.h"

/******************************************************************************************************************************************
 * 系统时钟设定
 *****************************************************************************************************************************************/
#define SYS_CLK_20MHz 0 //0 内部高频20MHz RC振荡器
#define SYS_CLK_40MHz 1 //1 内部高频40MHz RC振荡器
#define SYS_CLK_32KHz 2 //2 内部低频32KHz RC振荡器
#define SYS_CLK_XTAL 3  //3 外部晶体振荡器（2-30MHz）
#define SYS_CLK_PLL 4   //4 片内锁相环输出

#define SYS_CLK SYS_CLK_PLL

#define SYS_CLK_DIV_1 0
#define SYS_CLK_DIV_2 1

#define SYS_CLK_DIV SYS_CLK_DIV_1

#define __HSI (20000000UL) //高速内部时钟
#define __LSI (32000UL)    //低速内部时钟
#define __HSE (20000000UL) //高速外部时钟

/********************************** PLL 设定 **********************************************
 * VCO输出频率 = PLL输入时钟 / INDIV * 4 * FBDIV
 * PLL输出频率 = PLL输入时钟 / INDIV * 4 * FBDIV / OUTDIV = VCO输出频率 / OUTDIV
 *****************************************************************************************/
#define SYS_PLL_SRC SYS_CLK_20MHz //可取值SYS_CLK_20MHz、SYS_CLK_XTAL

#define PLL_IN_DIV 5

#define PLL_FB_DIV 60

#define PLL_OUT_DIV8 0
#define PLL_OUT_DIV4 1
#define PLL_OUT_DIV2 2

#define PLL_OUT_DIV PLL_OUT_DIV8

uint32_t SystemCoreClock = __HSI;         //System Clock Frequency (Core Clock)
uint32_t CyclesPerUs = (__HSI / 1000000); //Cycles per micro second

/******************************************************************************************************************************************
* 函数名称:
* 功能说明: This function is used to update the variable SystemCoreClock and must be called whenever the core clock is changed
* 输    入:
* 输    出:
* 注意事项:
******************************************************************************************************************************************/
void SystemCoreClockUpdate(void)
{
    if (SYS->CLKSEL & SYS_CLKSEL_SYS_Msk) //SYS_CLK  <= HFCK
    {
        if (SYS->CLKSEL & SYS_CLKSEL_HFCK_Msk) //HFCK <= XTAL
        {
            SystemCoreClock = __HSE;
        }
        else //HFCK <= HRC
        {
            if (SYS->HRCCR & SYS_HRCCR_DBL_Msk) //HRC = 40MHz
            {
                SystemCoreClock = __HSI * 2;
            }
            else //HRC = 20MHz
            {
                SystemCoreClock = __HSI;
            }
        }
    }
    else //SYS_CLK  <= LFCK
    {
        if (SYS->CLKSEL & SYS_CLKSEL_LFCK_Msk) //LFCK <= PLL
        {
            if (SYS->PLLCR & SYS_PLLCR_INSEL_Msk) //PLL_SRC <= HRC
            {
                SystemCoreClock = __HSI;
            }
            else //PLL_SRC <= XTAL
            {
                SystemCoreClock = __HSE;
            }

            SystemCoreClock = SystemCoreClock / PLL_IN_DIV * PLL_FB_DIV * 4 / (2 << (2 - PLL_OUT_DIV));
        }
        else //LFCK <= LRC
        {
            SystemCoreClock = __LSI;
        }
    }

    if (SYS->CLKDIV & SYS_CLKDIV_SYS_Msk)
        SystemCoreClock /= 2;

    CyclesPerUs = SystemCoreClock / 1000000;
}

/******************************************************************************************************************************************
* 函数名称:
* 功能说明: The necessary initializaiton of systerm
* 输    入:
* 输    出:
* 注意事项:
******************************************************************************************************************************************/
void SystemInit(void)
{
    SYS->CLKEN |= (1 << SYS_CLKEN_ANAC_Pos);

    switch (SYS_CLK)
    {
    case SYS_CLK_20MHz: //0 内部高频20MHz RC振荡器
        switchCLK_20MHz();
        break;

    case SYS_CLK_40MHz: //1 内部高频40MHz RC振荡器
        switchCLK_40MHz();
        break;

    case SYS_CLK_32KHz: //2 内部低频32KHz RC振荡器
        switchCLK_32KHz();
        break;

    case SYS_CLK_XTAL: //3 外部晶体振荡器（2-30MHz）
        switchCLK_XTAL();
        break;

    case SYS_CLK_PLL: //4 片内锁相环输出
        switchCLK_PLL();
        break;
    }

    SYS->CLKDIV &= ~SYS_CLKDIV_SYS_Msk;
    SYS->CLKDIV |= (SYS_CLK_DIV << SYS_CLKDIV_SYS_Pos);

    SystemCoreClockUpdate();
}

void switchCLK_20MHz(void)
{
    uint32_t i;

    SYS->HRCCR = (0 << SYS_HRCCR_OFF_Pos) |
                 (0 << SYS_HRCCR_DBL_Pos); //HRC = 20MHz

    for (i = 0; i < 1000; i++)
        __NOP();

    SYS->CLKSEL &= ~SYS_CLKSEL_HFCK_Msk;      //HFCK  <=  HRC
    SYS->CLKSEL |= (1 << SYS_CLKSEL_SYS_Pos); //SYS_CLK  <= HFCK
}

void switchCLK_40MHz(void)
{
    uint32_t i;

    SYS->HRCCR = (0 << SYS_HRCCR_OFF_Pos) |
                 (1 << SYS_HRCCR_DBL_Pos); //HRC = 40MHz

    for (i = 0; i < 1000; i++)
        __NOP();

    SYS->CLKSEL &= ~SYS_CLKSEL_HFCK_Msk;      //HFCK  <=  HRC
    SYS->CLKSEL |= (1 << SYS_CLKSEL_SYS_Pos); //SYS_CLK  <= HFCK
}

void switchCLK_32KHz(void)
{
    uint32_t i;

    SYS->CLKEN |= (1 << SYS_CLKEN_RTCBKP_Pos);

    SYS->LRCCR &= ~(1 << SYS_LRCCR_OFF_Pos);

    for (i = 0; i < 100; i++)
        __NOP();

    SYS->CLKSEL &= ~SYS_CLKSEL_LFCK_Msk; //LFCK  <=  LRC
    SYS->CLKSEL &= ~SYS_CLKSEL_SYS_Msk;  //SYS_CLK  <= LFCK
}

void switchCLK_XTAL(void)
{
    uint32_t i;

    SYS->XTALCR = (1 << SYS_XTALCR_EN_Pos);

    for (i = 0; i < 1000; i++)
        __NOP();

    SYS->CLKSEL |= (1 << SYS_CLKSEL_HFCK_Pos); //HFCK  <=  XTAL
    SYS->CLKSEL |= (1 << SYS_CLKSEL_SYS_Pos);  //SYS_CLK  <= HFCK
}

void switchCLK_PLL(void)
{
    uint32_t i;

    PLLInit();
    SYS->PLLCR |= (1 << SYS_PLLCR_OUTEN_Pos);

    for (i = 0; i < 10000; i++)
        __NOP();

    SYS->CLKSEL |= (1 << SYS_CLKSEL_LFCK_Pos); //LFCK  <=  PLL
    SYS->CLKSEL &= ~SYS_CLKSEL_SYS_Msk;        //SYS_CLK  <= LFCK
}

void PLLInit(void)
{
    uint32_t i;

    if (SYS_PLL_SRC == SYS_CLK_20MHz)
    {
        SYS->HRCCR = (0 << SYS_HRCCR_OFF_Pos) |
                     (0 << SYS_HRCCR_DBL_Pos); //HRC = 20MHz

        for (i = 0; i < 1000; i++)
            __NOP();

        SYS->PLLCR |= (1 << SYS_PLLCR_INSEL_Pos); //PLL_SRC <= HRC
    }
    else if (SYS_PLL_SRC == SYS_CLK_XTAL)
    {
        SYS->XTALCR = (1 << SYS_XTALCR_EN_Pos);

        for (i = 0; i < 20000; i++)
            ;

        SYS->PLLCR &= ~(1 << SYS_PLLCR_INSEL_Pos); //PLL_SRC <= XTAL
    }

    SYS->PLLDIV &= ~(SYS_PLLDIV_INDIV_Msk |
                     SYS_PLLDIV_FBDIV_Msk |
                     SYS_PLLDIV_OUTDIV_Msk);
    SYS->PLLDIV |= (PLL_IN_DIV << SYS_PLLDIV_INDIV_Pos) |
                   (PLL_FB_DIV << SYS_PLLDIV_FBDIV_Pos) |
                   (PLL_OUT_DIV << SYS_PLLDIV_OUTDIV_Pos);

    SYS->PLLCR &= ~(1 << SYS_PLLCR_OFF_Pos);

    while (SYS->PLLLOCK == 0)
        ; //等待PLL锁定
}