配置PCA的一点总结12单片机

先看代码

#include "stc12.h"

unsigned int Last_Capture_Data=0; 
unsigned int New_Capture_Data=0;  
unsigned int g_Period=0;      
unsigned int g_Frequency=0;  
unsigned char str1[12];
unsigned char str2[12]; 
bit Capture_over = 0;


sbit KEY_1 = P2^7;

extern void InitLcd1602();
extern void LcdShowStr(unsigned char x, unsigned char y, unsigned char *str);

void Delay50ms();
void PCA_Init (bit module);
void IntToString(unsigned char *str, unsigned int dat);

void main (void)
{
    PCA_Init(0);
    InitLcd1602();
    P2 = 0xF7;

    while(1)
    {
        if(!KEY_1)
        {
            Delay50ms();
            if(!KEY_1)      
            {
                while(!KEY_1);
                CCAPM0 = 0x11;
                CR = 1;
            }
        }

        if(Capture_over)
        {
            Capture_over = 0;
//                           g_Frequency = (long)1000000 / g_Period; 
            g_Frequency = (long)11059200 / (g_Period * 12);

            IntToString(str1, g_Period);
            IntToString(str2, g_Frequency);
            LcdShowStr(1, 0, "length:");
            LcdShowStr(8, 0, str1);
            LcdShowStr(1, 1, "freque:");
            LcdShowStr(8, 1, str2);

        }
    }
}


void PCA_Init (bit module)
{
    //CIDL    -       -       -       CPS2    CPS1    CPS0    ECF
    CMOD = 0x80;

    //CF      CR      -       -       -       -       CCF1    CCF0
    CCON = 0x00;

    if (module == 0)                
    {
        CCAPM0 = 0x10;
        CCAP0L = 0x00;
        CCAP0H = 0x00;
    }
    else                                 
    {
        CCAPM1 = 0x11;
        CCAP1L = 0x00;
        CCAP1H = 0x00;
    }


    CL = 0x00;                
    CH = 0x00;

    EA = 1;

    //CR = 1;                     
}

void IntToString(unsigned char *str, unsigned int dat)
{
    unsigned char buf[12];
    unsigned char i = 0;
    do{
        buf[i++] = dat % 10;
        dat /= 10; 
    }while(dat > 0);

    while(i-- > 0)
    {
        *str++ = buf[i] + '0';//数组转换成ASCII反向拷贝到字符串指针
    }
    *str = '\0';
}

void PCA_Int(void) interrupt 7
{
    if (CCF0)                   
    {
        CCF0 = 0; 
        if(Last_Capture_Data == 0)
        {
              Last_Capture_Data = CCAP0H; 

              Last_Capture_Data = (Last_Capture_Data << 8) + CCAP0L; 
        }
        else 
        {            
            New_Capture_Data = CCAP0H;         

            New_Capture_Data = (New_Capture_Data << 8) + CCAP0L;
            g_Period = New_Capture_Data - Last_Capture_Data;
            CR = 0;
            CCAPM0 = 0x10;

            Last_Capture_Data=0;  
            CCAP0L = 0x00;
            CCAP0H = 0x00;
            CL = 0x00;                 
            CH = 0x00;

            Capture_over = 1;
        }
    }

}

void Delay50ms()        //@11.0592MHz
{
    unsigned char i, j, k;

    i = 3;
    j = 26;
    k = 223;
    do
    {
        do
        {
            while (--k);
        } while (--j);
    } while (--i);
}

配置流程：

1. CMOD 设置禁止溢出中断
2. 设置CCAPMx设置开启捕获中断，以及上升沿捕获还是下降沿捕获
3. 清零CCnPL、CCnPH以及CH、CL

其实最重要的还得看手册，介绍的真心很详细！！！

一个非常详细的电路图，分分享一下：

很明显，图的意思就是设置好上升沿捕获或者下降沿捕获后，由于CL、CH
一直在走，一旦满足条件就把CL./CH的值分别装入CCAPL以及CCAPH中，如果此时使能PCA中断的话，会触发中断进入中断。