PIC18F中断定时器

//基于MCC18编译器，使用HI-PICC不可用
//--------------------------------------------   #include <p18F452.h>
//----------------------------------------------------------------------------
void main (void);
void InterruptHandlerHigh (void);
unsigned int Timeout;
//----------------------------------------------------------------------------
// Main routine
void main ()
{
        Timeout = 0;
        INTCON = 0x20;                 //disable global and enable TMR0 interrupt
        INTCON2 = 0x84;               //TMR0 high priority
        RCONbits.IPEN = 1;            //enable priority levels
        TMR0H = 0;                      //clear timer
        TMR0L = 0;                      //clear timer
        T0CON = 0x82;                //set up timer0 - prescaler 1:8
        INTCONbits.GIEH = 1;       //enable interrupts
        TRISD = 0; /* configure PORTD for output */
        PORTD=0X00;
        while (1)
        {
             if (Timeout == 1)
            {                                  //timeout?
                   Timeout = 0;          //clear timeout indicor
                   PORTD++;              //PORTD端口二进制计数
          }
        }
 } 

PIC18F452定时器中断@ZSTU
//----------------------------------------------------------------------------
 // High priority interrupt vector
#pragma code InterruptVectorHigh = 0x08
void  InterruptVectorHigh (void)
{    _asm
      goto InterruptHandlerHigh //jump to interrupt routine
    _endasm
}
//----------------------------------------------------------------------------
// High priority interrupt routine
#pragma code
#pragma interrupt InterruptHandlerHigh
void  InterruptHandlerHigh ()
{
      if (INTCONbits.TMR0IF)
     {   //check for TMR0 overflow
         INTCONbits.TMR0IF = 0;            //clear interrupt flag
         Timeout = 1;                          //indicate timeout
      }
}
 //----------------------------------------------------------------------------

PIC18F4520单片机提供多个中断源及一个中断优先级功能,可以给大多数中断源分配高优先级或者低优先级.高优先级中断向量地址为0008H，低优先级中断向量地址为0018H。高优先级中断事伯将中断所有可参正在进行的低优先级中断。
     有10个寄存器用于控制中断的操作。它们是：
RCON
INTCON
INTCON2
INTCON3
PIR1和PIR2
PIE1和PIE2
IPR1和IPR2
通常，用三个位控制中断源的操作。

标志位 表明发生了中断事件
使能位 允许程序跳转转到中断向量地址处执行（当标志位置1时）
优先级 用于选择是高优先级还是低先级，通过将IPEN位（RCON<7>）置1，可使能中断优先级功能。当使能中断优先级时，有2位可使能全局中断。将GIEH位（INTCON<7>）置1，可使能所有优先级位置1（高优先级）的中断。将GIEL位（INTCON<6>）置1，可使能所有优先级位清零（低优先级）的中断。
当中断标志位、使能位以及相应的全局中断使能位均被置1时，程序将立即跳转到中断地址0008H或0018H，具体地址取决于优先级位的设置。通过设置相应的使能位可以禁止单个中断。
 注意：系统复位时IPEN位为零（默认状态）时，便会禁止中断优先级功能，此时中断与PIC16系统中档单片机相兼容。在兼容模式下，所有中断均跳转到地址0008H执行。

下面是在SP9608-PIC增强型单片机开发板利用PIC18F4520单片机来实现的数字频率计数器功能，程序中使用了T0用为外部信号源输入，通TMR0来实现对信号源的频率计数。TMR3作为定时器，来产生1mS数码管扫描时基和1S秒时基信号。为了提高频率计数的准确度，采用中断嵌套技术来完成，将TMR3产生1mS的定时信号作为高优先级中断，TMR0作为频率计数溢出中断作为低先级中断。源程序采用MCC18编译器和MPLAB7.50版本的集成开发环境，调试工具采用ICD2；具体源程序如下：
   系统时钟：采用外部的12MHz晶振经过内部PLL的4倍频到48MHz。（HS-PLL配置位）

 #include <p18cxxx.h>
 #define TRUE 1
 #define FALSE 0
 #define HIGH 1
 #define LOW 0
 rom unsigned char LEDDATA[]=
 {
     0x3F,0x06,0x5B,0x4F,0x66,
     0x6D,0x7D,0x07,0x7F,0x6F,
     0x40,0x00,
 };
 struct TIMER_STRUCT
 {
 unsigned int Interval;
 unsigned char Enable;
 };
 struct TIMER_STRUCT Timer1S;
 struct T0_T1_STRUCT
 {
 unsigned int High_Byte;
 unsigned int Low_Byte;
 unsigned long Result;
 };
 struct T0_T1_STRUCT My_T0,My_T1;
 struct LED_STRUCT
 {
 unsigned char DotPointer;
 unsigned char ScanPointer;
 unsigned char Buffer[];
 };
 struct LED_STRUCT NumberLED;
 void PIC18F_High_isr (void);
 void PIC18F_Low_isr (void);
 #pragma code high_vector_section=0x8
 void high_vector (void)
 {
 _asm goto PIC18F_High_isr _endasm
 }
 #pragma code low_vector_section=0x18
 void low_vector (void)
 {
 _asm goto PIC18F_Low_isr _endasm
 }
 #pragma code
 //---中断高优先级---//
 #pragma interrupt PIC18F_High_isr
 void PIC18F_High_isr (void)
 {
 if(TRUE==PIR2bits.TMR3IF)
     {
    PIR2bits.TMR3IF=FALSE;
       TMR3H=(-)/;
       TMR3L=(-)%;

      if(FALSE==Timer1S.Enable)
        {
       Timer1S.Interval++;
       if(==Timer1S.Interval)
         {
        T0CONbits.TMR0ON=FALSE;
        Timer1S.Interval=;
        Timer1S.Enable=TRUE;
      }
     }

    if(LOW==LATAbits.LATA0)LATAbits.LATA0=HIGH;
      else LATAbits.LATA0=LOW;

       LATD=LEDDATA[NumberLED.Buffer[NumberLED.ScanPointer]];
       LATE=NumberLED.ScanPointer;
       NumberLED.ScanPointer++;      if(NumberLED.ScanPointer==sizeof(NumberLED.Buffer))NumberLED.ScanPointer=;
 }
 }
 //---中断低优先级---//
 #pragma interruptlow PIC18F_Low_isr
 void PIC18F_Low_isr (void)
 {
 if(TRUE==INTCONbits.TMR0IF)
     {
    INTCONbits.TMR0IF=FALSE;
    My_T0.High_Byte++;
 }

 }
 void main(void)
 {
 unsigned int i;
 unsigned long temp;

 Timer1S.Enable=FALSE;
 Timer1S.Interval=;
 My_T0.High_Byte=;
 My_T0.Low_Byte=;
 My_T1.High_Byte=;
 My_T1.Low_Byte=;
 for(i=;i<sizeof(NumberLED.Buffer);i++)NumberLED.Buffer[i]=;
 NumberLED.ScanPointer=;
 NumberLED.DotPointer=;
 TRISAbits.TRISA0=;
 LATAbits.LATA0=;
 TRISD=;
 LATD=;
 TRISE=;
 LATE=;
 T0CONbits.TMR0ON=FALSE;
 TMR0L=;
 TMR0H=;
 T0CONbits.T0CS=;
 T0CONbits.T0SE=;
 T0CONbits.PSA=;
 T0CONbits.T08BIT=;
 INTCONbits.T0IF=FALSE;
 INTCONbits.T0IE=TRUE;
 T0CONbits.TMR0ON=TRUE;
 T3CON=0x00;
 TMR3H=(-)/;
 TMR3L=(-)%;
 PIR2bits.TMR3IF=FALSE;
 PIE2bits.TMR3IE=TRUE;
 T3CONbits.TMR3ON=TRUE;
 INTCONbits.GIEH=TRUE;
 INTCONbits.GIEL=TRUE;
 RCONbits.IPEN=TRUE;
 //---设置中断优先级---//
 INTCON2bits.TMR0IP=FALSE;
 IPR2bits.TMR3IP=TRUE;

 while()
     {
    if(TRUE==Timer1S.Enable)
      {
     My_T0.Result=;
     My_T0.Result=My_T0.High_Byte;
     My_T0.Result<<=;
     My_T0.Result|=TMR0L;
     temp=My_T0.Result;
     for(i=;i<sizeof(NumberLED.Buffer);i++)NumberLED.Buffer[i]=;
     i=;
     while(temp)
       {
      NumberLED.Buffer[i]=temp%;
      temp/=;
      i++;
     }
     TMR0L=;
     TMR0H=;
     My_T0.Low_Byte=;
     My_T0.High_Byte=;
     Timer1S.Enable=FALSE;
     T0CONbits.TMR0ON=TRUE;
    }
 }
 }