demo_9_3.i

mega16的中断4*4键盘扫描

// CodeVisionAVR C Compiler
// (C) 1998-2001 Pavel Haiduc, HP InfoTech S.R.L.

// I/O registers definitions for the ATmega16


#pragma used+
sfrb TWBR=0;
sfrb TWSR=1;
sfrb TWAR=2;
sfrb TWDR=3;
sfrb ADCL=4;
sfrb ADCH=5;
sfrw ADCW=4;      // 16 bit access
sfrb ADCSRA=6;
sfrb ADMUX=7;
sfrb ACSR=8;
sfrb UBRRL=9;
sfrb UCSRB=0xa;
sfrb UCSRA=0xb;
sfrb UDR=0xc;
sfrb SPCR=0xd;
sfrb SPSR=0xe;
sfrb SPDR=0xf;
sfrb PIND=0x10;
sfrb DDRD=0x11;
sfrb PORTD=0x12;
sfrb PINC=0x13;
sfrb DDRC=0x14;
sfrb PORTC=0x15;
sfrb PINB=0x16;
sfrb DDRB=0x17;
sfrb PORTB=0x18;
sfrb PINA=0x19;
sfrb DDRA=0x1a;
sfrb PORTA=0x1b;
sfrb EECR=0x1c;
sfrb EEDR=0x1d;
sfrb EEARL=0x1e;
sfrb EEARH=0x1f;
sfrw EEAR=0x1e;   // 16 bit access
sfrb UBRRH=0x20;
sfrb UCSRC=0X20;
sfrb WDTCR=0x21;
sfrb ASSR=0x22;
sfrb OCR2=0x23;
sfrb TCNT2=0x24;
sfrb TCCR2=0x25;
sfrb ICR1L=0x26;
sfrb ICR1H=0x27;
sfrb OCR1BL=0x28;
sfrb OCR1BH=0x29;
sfrw OCR1B=0x28;  // 16 bit access
sfrb OCR1AL=0x2a;
sfrb OCR1AH=0x2b;
sfrw OCR1A=0x2a;  // 16 bit access
sfrb TCNT1L=0x2c;
sfrb TCNT1H=0x2d;
sfrw TCNT1=0x2c;  // 16 bit access
sfrb TCCR1B=0x2e;
sfrb TCCR1A=0x2f;
sfrb SFIOR=0x30;
sfrb OSCCAL=0x31;
sfrb OCDR=0x31;
sfrb TCNT0=0x32;
sfrb TCCR0=0x33;
sfrb MCUCSR=0x34;
sfrb MCUCR=0x35;
sfrb TWCR=0x36;
sfrb SPMCR=0x37;
sfrb TIFR=0x38;
sfrb TIMSK=0x39;
sfrb GIFR=0x3a;
sfrb GICR=0x3b;
sfrb OCR0=0X3c;
sfrb SPL=0x3d;
sfrb SPH=0x3e;
sfrb SREG=0x3f;
#pragma used-

// Interrupt vectors definitions


// Needed by the power management functions (sleep.h)
#asm
	#ifndef __SLEEP_DEFINED__
	#define __SLEEP_DEFINED__
	.EQU __se_bit=0x40
	.EQU __sm_mask=0xB0
	.EQU __sm_powerdown=0x20
	.EQU __sm_powersave=0x30
	.EQU __sm_standby=0xA0
	.EQU __sm_ext_standby=0xB0
	.EQU __sm_adc_noise_red=0x10
	.SET power_ctrl_reg=mcucr
	#endif
#endasm


// CodeVisionAVR C Compiler
// (C) 1998-2000 Pavel Haiduc, HP InfoTech S.R.L.


#pragma used+

void delay_us(unsigned int n);
void delay_ms(unsigned int n);

#pragma used-

flash unsigned char led[16]={0x28,0xeb,0x19,0x89,0xca,0x8c,0x0c,0xe9,0x08,0x88,
                             0xdf,0x4a,0x1c,0x3e,0x7e,0x2a};
unsigned char	key_stime_counter;
unsigned char   key_temp;
bit	key_stime_ok; 
//D0接键盘，低4位列线输入，高4位行线输出
unsigned char read_keyboard()
{	
 static unsigned char key_state = 0, key_value, key_line;
 unsigned char key_return = 255,i;
 switch (key_state)
 {
  case 0:
  	key_line = 0b00010000;
  	for (i=1; i<=4; i++)			// 扫描键盘
  	{	
         PORTA = ~key_line;			// 输出行线电平
	 PORTA = ~key_line;			// 必须送2次！！！
	 key_value = 0b00001111   & PINA;		// 读列电平
	 if (key_value == 0b00001111  )
	 key_line <<= 1;			// 没有按键，继续扫描
	 else
	 {
	  key_state++;				// 有按键，停止扫描
	  break;				// 转消抖确认状态
	 }
	}
	break;
  case 1:
        if (key_value == (0b00001111   & PINA))	// 再次读列电平，
	{
	 switch (key_line | key_value)		// 与状态0的相同，确认按键
	 {					// 键盘编码，返回编码值 
	  case 0b00011110:
	       key_return = 1;
	       break;
	  case 0b00011101:
	       key_return = 2;
	       break;
          case 0b00011011:
	       key_return = 3;
	       break;
	  case 0b00010111:
	       key_return = 4;
	       break;     
	  case 0b00101110:
	       key_return = 5;
	       break;
 	  case 0b00101101:
	       key_return = 6;
	       break;
	  case 0b00101011:
	       key_return = 7;
	       break;
	  case 0b00100111:
	       key_return = 8;
	       break;
 	  case 0b01001110:
	       key_return = 9;
	       break;
 	  case 0b01001101:
	       key_return = 0;
	       break;
	  case 0b01001011:
	       key_return = 10;
	       break; 
	  case 0b01000111:
	       key_return = 11;
	       break;
 	  case 0b10001110:
	       key_return = 12;
	       break;
 	  case 0b10001101:
	       key_return = 13;
	       break;
	  case 0b10001011:
	       key_return = 14;
	       break; 
	  case 0b10000111:
	       key_return = 15;
	       break;
	 }
	key_state++;				// 转入等待按键释放状态
       }
       else
	 {
	  key_state--;
	  delay_ms(5);
	 }				// 两次列电平不同返回状态0，（消抖处理）
	 break;						
  case 2:					// 等待按键释放状态
      PORTA = 0b00001111;			// 行线全部输出低电平
      PORTA = 0b00001111;			// 重复送一次
      if ( (0b00001111   & PINA) == 0b00001111  )
      key_state=0;				// 列线全部为高电平返回状态0
      break;
 }
 return key_return;
}
//向数码管送入数据
void sendbyte(unsigned char byte)
{    
 unsigned char num,c; 
 num=led[byte];
 for(c=0;c<8;c++)
 {
  PORTB.1 =0;
  PORTB.0=num&0x01;
  PORTB.1 =1;
  num>>=1;
 }
}
void display(void)
{
 if (key_stime_ok)				
  {
   key_stime_ok = 0;		// 10ms到
   key_temp = read_keyboard();	// 调用键盘接口函数读键盘
   if (key_temp != 255)
   {				// 有按键按下
    sendbyte(key_temp);
    delay_ms(10);
   }
  }
}
void main(void)
{
 DDRB = 0xFF;
 //PORTC = 0xFF;			// 键盘接口初始化
 DDRA = 0xF0;			// PD2、PD1、PD0列线，输入方式，上拉有效
 // T/C0 初始化 
 TCCR0=0x0B;			// 内部时钟，64分频（4M/64=62.5KHz），CTC模式
 TCNT0=0x00;
 OCR0=0x7C;			// OCR0 = 0x7C(124),(124+1)/62.5=2ms
 TIMSK=0x02;			// 允许T/C0比较匹配中断
 #asm("sei")			// 开放全局中断
 while (1)
 {
  display();
 }
}     
// Timer 0 比较匹配中断服务,2ms定时
interrupt [20] void timer0_comp_isr(void)
{
 //display();					// 调用LED扫描显示
 if (++key_stime_counter >=5)
 {
  key_stime_counter = 0;
  key_stime_ok = 1;				// 10ms到
 }	
}