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）

  1 #include <p18cxxx.h>
  2 #define TRUE 1
  3 #define FALSE 0
  4 #define HIGH 1
  5 #define LOW 0
  6 rom unsigned char LEDDATA[]=
  7 {
  8     0x3F,0x06,0x5B,0x4F,0x66,
  9     0x6D,0x7D,0x07,0x7F,0x6F,
 10     0x40,0x00,
 11 };
 12 struct TIMER_STRUCT
 13 {
 14 unsigned int Interval;
 15 unsigned char Enable;
 16 };
 17 struct TIMER_STRUCT Timer1S;
 18 struct T0_T1_STRUCT
 19 {
 20 unsigned int High_Byte;
 21 unsigned int Low_Byte;
 22 unsigned long Result;
 23 };
 24 struct T0_T1_STRUCT My_T0,My_T1;
 25 struct LED_STRUCT
 26 {
 27 unsigned char DotPointer;
 28 unsigned char ScanPointer;
 29 unsigned char Buffer[8];
 30 };
 31 struct LED_STRUCT NumberLED;
 32 void PIC18F_High_isr (void);
 33 void PIC18F_Low_isr (void);
 34 #pragma code high_vector_section=0x8
 35 void high_vector (void)
 36 {
 37 _asm goto PIC18F_High_isr _endasm
 38 }
 39 #pragma code low_vector_section=0x18
 40 void low_vector (void)
 41 {
 42 _asm goto PIC18F_Low_isr _endasm
 43 }
 44 #pragma code
 45 //---中断高优先级---//
 46 #pragma interrupt PIC18F_High_isr
 47 void PIC18F_High_isr (void)
 48 {
 49 if(TRUE==PIR2bits.TMR3IF)
 50     {
 51    PIR2bits.TMR3IF=FALSE;
 52       TMR3H=(65536-11965)/256;
 53       TMR3L=(65536-11965)%256;
 54         
 55      if(FALSE==Timer1S.Enable)
 56        {
 57       Timer1S.Interval++;
 58       if(1000==Timer1S.Interval)
 59         {
 60        T0CONbits.TMR0ON=FALSE;
 61        Timer1S.Interval=0;
 62        Timer1S.Enable=TRUE;
 63      }
 64     }
 65     
 66    if(LOW==LATAbits.LATA0)LATAbits.LATA0=HIGH;
 67      else LATAbits.LATA0=LOW;
 68      
 69       LATD=LEDDATA[NumberLED.Buffer[NumberLED.ScanPointer]];
 70       LATE=NumberLED.ScanPointer;
 71       NumberLED.ScanPointer++;      if(NumberLED.ScanPointer==sizeof(NumberLED.Buffer))NumberLED.ScanPointer=0;
 72 }
 73 }
 74 //---中断低优先级---//
 75 #pragma interruptlow PIC18F_Low_isr
 76 void PIC18F_Low_isr (void)
 77 {
 78 if(TRUE==INTCONbits.TMR0IF)
 79     {
 80    INTCONbits.TMR0IF=FALSE;
 81    My_T0.High_Byte++;    
 82 }
 83 
 84 }
 85 void main(void)
 86 {
 87 unsigned int i;
 88 unsigned long temp;
 89 
 90 Timer1S.Enable=FALSE;
 91 Timer1S.Interval=0;
 92 My_T0.High_Byte=0;
 93 My_T0.Low_Byte=0;
 94 My_T1.High_Byte=0;
 95 My_T1.Low_Byte=0;
 96 for(i=0;i<sizeof(NumberLED.Buffer);i++)NumberLED.Buffer[i]=0;
 97 NumberLED.ScanPointer=0;
 98 NumberLED.DotPointer=0;
 99 TRISAbits.TRISA0=0;
100 LATAbits.LATA0=0;
101 TRISD=0;
102 LATD=0;
103 TRISE=0;
104 LATE=0;
105 T0CONbits.TMR0ON=FALSE;
106 TMR0L=0;
107 TMR0H=0;
108 T0CONbits.T0CS=1;
109 T0CONbits.T0SE=0;
110 T0CONbits.PSA=1;
111 T0CONbits.T08BIT=1;
112 INTCONbits.T0IF=FALSE;
113 INTCONbits.T0IE=TRUE;
114 T0CONbits.TMR0ON=TRUE;
115 T3CON=0x00;
116 TMR3H=(65536-12000)/256;
117 TMR3L=(65536-12000)%256;
118 PIR2bits.TMR3IF=FALSE;
119 PIE2bits.TMR3IE=TRUE;
120 T3CONbits.TMR3ON=TRUE;
121 INTCONbits.GIEH=TRUE;
122 INTCONbits.GIEL=TRUE;
123 RCONbits.IPEN=TRUE;
124 //---设置中断优先级---//
125 INTCON2bits.TMR0IP=FALSE;
126 IPR2bits.TMR3IP=TRUE;
127 
128 while(1)
129     {
130    if(TRUE==Timer1S.Enable)
131      {
132     My_T0.Result=0;
133     My_T0.Result=My_T0.High_Byte;
134     My_T0.Result<<=8;
135     My_T0.Result|=TMR0L;
136     temp=My_T0.Result;
137     for(i=0;i<sizeof(NumberLED.Buffer);i++)NumberLED.Buffer[i]=0;
138     i=0;
139     while(temp)
140       {
141      NumberLED.Buffer[i]=temp%10;
142      temp/=10;
143      i++;    
144     }
145     TMR0L=0;
146     TMR0H=0;
147     My_T0.Low_Byte=0;
148     My_T0.High_Byte=0;
149     Timer1S.Enable=FALSE;
150     T0CONbits.TMR0ON=TRUE;
151    }
152 }
153 }