External interrupt (button) controls the digital tube display

#define uint  unsigned int
#define uchar unsigned char
#define ulong unsigned long

#define  SIGNAL  P3_5     //  Keyboard initial signal

#define  KEY6   P3_2     //  KEY6 port is INT0 port
#define  KEY2   P3_3

int whether;

//  延时约(0.001 * n)秒
void delay(unsigned char n)
{
    ulong i;
    do {
        i = CPUCLK / 1000;
  while(i--);
    } while (--n != 0);
}

void int0() interrupt 0   // It is also possible not to determine whether KEY6 is pressed, because it is the KEY6 key that triggers this interrupt
{
 if(KEY6 == 0)
 {
  delay(10);       //  Delay to eliminate key jitterif
  (KEY6 == 0)      //  Confirm that a key is pressed
  {      
   num++;
   if (num > 9)
    num = 0;
   P0 = num;
  }
  while (!KEY6)  ;      //  Wait for KEY1 to be releaseddelay
  (10);       //  Delay to eliminate key release jitter
 }
}

void int1() interrupt 2        
{
 if(KEY2 == 0)     
 {
  delay(10);       //  Delay to eliminate key jitter
  if (KEY2 == 0)      //  Confirm that a key is pressed
  {      
   num--;
   if (num < 0)
    num = 9;
   P0 = num;
  }
  while (!KEY2)  ;      //  Wait for KEY1 to be released
  delay(10);       //  Delay to eliminate key release jitter
 }
}

//  External interrupt initialization function
void int_init()
{
 EA = 1;        //  Open general interrupt
 EX0 = 1;        //  Open external interrupt 0
 IT0 = 0;        //  External interrupt 0 low level trigger mode
 EX1 = 1;
 IT1 = 0;
}

//  Main program entry
void main(void)
{
 int_init();
 SIGNAL = 0;       //  Important!! Although SIGNAL and IT1 are at the same address, SIGNAL must be initialized
 
 num = 0;
 P0 = num;
 
 for (;;){
 }
}

External interrupt program design steps:

1. Enable general interrupt

2. External interrupt

3. Set the external interrupt trigger mode

4. Interrupt Handler