PIC16F877A秒表的设计问题？

只看该作者 · 2016-6-2 20:03

本帖最后由冰封小肥牛于 2016-6-2 20:06 编辑

打算用16F877A设计一个秒表，然后用数码管显示出来。最低两位数码管用来显示毫秒（0--100）变化范围，每隔10ms（使用的是定时器0的中断）计数加一次。但是现在显示的数码管有问题，如图（只有最低位数码管在变化，而且两个数码管非常暗）。求解应该如何编写程序才能正确显示。下面是在下的编写的程序

只看该作者 · 2016-6-2 20:06

#include <xc.h>
#pragma config FOSC = HS       // Oscillator Selection bits (HS oscillator)
#pragma config WDTE = OFF       // Watchdog Timer Enable bit (WDT enabled)
#pragma config PWRTE = OFF    // Power-up Timer Enable bit (PWRT disabled)
#pragma config BOREN = OFF    // Brown-out Reset Enable bit (BOR enabled)
#pragma config LVP = OFF       // Low-Voltage (Single-Supply) In-Circuit Serial Programming Enable bit (RB3/PGM pin has PGM function; low-voltage programming enabled)
#pragma config CPD = OFF       // Data EEPROM Memory Code Protection bit (Data EEPROM code protection off)
#pragma config WRT = OFF       // Flash Program Memory Write Enable bits (Write protection off; all program memory may be written to by EECON control)
#pragma config CP = OFF       // Flash Program Memory Code Protection bit (Code protection off)

unsigned int i,ms;
const unsigned char table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f};       //共阴极数码管显示编码

void display(unsigned int seg_num);
void delay(unsigned int x);
void time0_init();

void main()
{
PORTD = 0x00;             //数码管位选
PORTA = 0x00;             //数码管段选
TRISA = 0x00;
TRISD = 0x00;
time0_init();
while(1)
{
      display(ms);
      if(ms == 99)          //毫秒加到100清0
      {
         ms = 0;
      }
}
}

void interrupt time0(void)    //中断函数
{
if(INTCONbits.T0IF == 1)
{
      INTCONbits.T0IF = 0;
      TMR0 = 0xD9;          //定时10MS
      ms++;                //过10MS加1
}
}

void delay(unsigned int x)    //延时函数
{
unsigned int a,b;
for(a=x;a>0;a--)
for(b=110;b>0;b--);
}

void display(unsigned int seg_num)
{
   unsigned int ms_dec,ms_un;
   ms_dec = seg_num/10;
   ms_un = seg_num%10;
   PORTAbits.RA0 = 1;          //段选最低位数码管（个位）
   PORTD = table[ms_un];       //毫秒个位显示
   PORTAbits.RA0 = 0;          //关段选
//    delay(1);
   PORTAbits.RA1 = 1;          //段选第二位数码管（十位）
   PORTD = table[ms_dec];
   PORTAbits.RA1 = 0;
//    delay(1);
}

void time0_init()
{
TMR0 = 0xD9;                   //定时器0的设置，采用64分频
INTCONbits.GIE = 1;
INTCONbits.T0IE = 1;
INTCONbits.T0IF = 0;
OPTION_REGbits.T0CS = 0;
OPTION_REGbits.PSA = 0;
OPTION_REGbits.PS0 = 1;
OPTION_REGbits.PS1 = 0;
OPTION_REGbits.PS2 = 1;
}