#include "PWM.h"

#define EN_EXT_OSC       0 

#define COMPLEMENT_MODE         0x00000020
#define DEAD_ZONE_INTERVAL      0xC8FF0000
#define PWM_ENABLE              0x01010101
 
#if     EN_EXT_OSC
#define PWM_CLOCK_SOURCE        0x00000000  //使用外部振蕩12MHz
#else 
#define PWM_CLOCK_SOURCE        0xF0000000  //使用內部RC振蕩22.1184MHz
#endif

#define PWM_PRESCALAE           0x0000C731  //PWM01預分頻0x31(49)，PWM23預分頻0xC7(199)
#define PWM_CLOCK_DIVIDER       0x00004444  //輸入時鐘分頻1
#define PWM_OUTPUT_INVERT       0x00040000
#define PWM_OUTPUT_ENABLE       0x0000000F   //PWM0、1、2、3輸出使能

#define PWM_CMR_VALUE   0x0
#define PWM_CNR_VALUE       0x1000      //4096 
/*
PWM頻率=PWMxy_CLK/(prescale+1)*(clock divider)/(CNR+1)
(1)使用外部晶振12MHz
PWM頻率=12000000/(49+1)*4097 =58.57Hz
(2)使用內部RC振蕩22.1184MHz 
PWM頻率=22118400/(49+1)*4097 =107.97Hz
*/
#define LED_DARKING             0
#define LED_BRIGHTING   1

STATIC UINT32 g_unPWMCMRValue=PWM_CNR_VALUE;
STATIC UINT32 g_unLedStat=LED_DARKING;
/****************************************
*函數名稱:PWMInit
*輸    入:無
*輸    出:無
*功    能:PWM初始化
******************************************/
VOID PWMInit(VOID)
{
    P2_MFP |= ~(P20_AD8_PWM0 | P21_AD9_PWM1 | P22_AD10_PWM2 | P23_AD11_PWM3);
 P2_MFP |= (PWM0 | PWM1 | PWM2 | PWM3);   //使能P2.0~P2.3為PWM輸出  
    P2_PMD &= ~Px0_PMD;                       //配置P2.0~P2.3為推挽輸出
 P2_PMD |= Px0_OUT;
 P2_PMD &= ~Px1_PMD;
 P2_PMD |= Px1_OUT;
 P2_PMD &= ~Px2_PMD;
 P2_PMD |= Px2_OUT;
 P2_PMD &= ~Px3_PMD;
 P2_PMD |= Px3_OUT;
    APBCLK |= PWM01_CLKEN | PWM23_CLKEN;                        //使能PWM0~3時鐘
 CLKSEL1 = PWM_CLOCK_SOURCE;                 //選擇PWM0~3時鐘源
   
 PPRA = PWM_PRESCALAE | DEAD_ZONE_INTERVAL;                  //選擇PWM0~3時鐘預分頻和死區間隔
    CSRA = PWM_CLOCK_DIVIDER;                                   //選擇PWM0~3時鐘分頻
    PCRA = 0x08080808 | PWM_OUTPUT_INVERT | COMPLEMENT_MODE;    //PWM0~3自動重裝載

    CNR0A = CNR1A = CNR2A = CNR3A = PWM_CNR_VALUE;              //PWM0~3計數值
    CMR0A = CMR1A = CMR2A = CMR3A = PWM_CMR_VALUE;              //PWM0~3比較值

    PIERA  |= PWMIE3 | PWMIE2 | PWMIE1 | PWMIE0 ;    //使能PWM0~3中斷
    NVIC_ISER |= PWMA_INT;                                      //使能PWM0~3中斷

    POEA = PWM_OUTPUT_ENABLE;                                   //PWM輸出使能
    PCRA |= PWM_ENABLE;                                         //PWM使能，啟動
}
/****************************************
*函數名稱:PWMA_IRQHandler
*輸    入:無
*輸    出:無
*功    能:中斷服務函數-PWMA
******************************************/
VOID PWMA_IRQHandler(VOID)
{
  switch(g_unLedStat)            //檢查LED狀態
  {
   case  LED_DARKING:         //LED狀態漸暗
  {
    if(g_unPWMCMRValue < PWM_CNR_VALUE)
    {
     g_unPWMCMRValue+=50;
    }
    else
    {
       g_unLedStat = LED_BRIGHTING;
     g_unPWMCMRValue=PWM_CNR_VALUE;
    }  
  }break;

  case  LED_BRIGHTING:         //LED狀態漸亮
  {
    if(g_unPWMCMRValue>=50)
    {
     g_unPWMCMRValue-=50;
    }
    else
    {
       g_unLedStat = LED_DARKING;
     g_unPWMCMRValue=PWM_CMR_VALUE;   
    }
  }break;
  default:break; 
  }
  CMR0A = CMR1A = CMR2A = CMR3A = g_unPWMCMRValue;  //設置PWM0~3比較值
     PIIRA = PIIRA;                          
}
/****************************************
*函數名稱:main
*輸    入:無
*輸    出:無
*功    能:函數主體
******************************************/
INT32 main(VOID)
{
   PROTECT_REG                         //ISP下載時保護FLASH存儲器
  (
   PWRCON |= XTL12M_EN;                   //默認時鐘源為外部晶振
   while((CLKSTATUS & XTL12M_STB) == 0);                //等待12MHz時鐘穩定  
   CLKSEL0 = (CLKSEL0 & (~HCLK)) | HCLK_12M;              //設置外部晶振為系統時鐘 
   PWMInit();              //PWM初始化
  )
     while(1);
}