main.c

方波发生器程序。AVR单片机程序。MEGA16

/***************************************
*              方波生成器              *
* 程序功能: 生成占空比可调方波         *
* 时钟频率: 外部7.3728M                *
* 设    计：莫锦攀                     *
* 修改日期：2007年07月26日             *
* 编译环境：ICC-AVR6.31                *
* 实验环境：M16学习板                  *
* 使用端口: LCD:PC6,PC7,PA4~PA7        *
*           KEY:PB0,PD2,PD3            *
* 程序说明：方波范围:28HZ~22800HZ，步进*
*           2HZ,低频时可以观测到LED闪烁*
*                                      *
***************************************/
#include <iom16v.h>
#include "1602.h"
#include "delay.h"

#define uchar unsigned char
#define uint  unsigned int

uchar get_key(void)
{
 unsigned char i;
 static unsigned char j;//按键记录 
 PORTD|=0x0c;//pd2,pd3上拉电阻
 DDRD&=0xf3;//pd2,pd3为输入


 if((PIND&0x04)==0)i='A';   
 else if((PIND&0x08)==0)i='B';
 else i=0x00;
    
 if (i == 0x00)//无有效按键按下
   {
    j = 0x00;//清除按键记录
    return 0x00;//程序退出
   }
   if (j == 0x00) //为新按键
    {j = i;//保存本次采样结果
     delay_nms(10);//去按键颤抖
     if((PIND&0x04)==0)i='A';   
     else if((PIND&0x08)==0)i='B';
     else i=0x00;	 
     if(i == j) {return i;}
    }
return 0x00;
}

void init_timer0(void)
{
 DDRB|=0x08;//OC0匹配输出
 TCNT0=0x00;//清除定时器值
 TCCR0=0x6d;//快速PWM模式,匹配时OC0清零,top时置数,系统时钟1024分频                                                              频,输出比较匹配清除定时器值
 

 OCR0=0x80;//OCR0置初值,占空比50%
 
}


void F_set(void)
{
 static unsigned char i;
 if(i!=5)i++;
 else i=1;
 switch(i)//频率选择
		  {
		   case 1:
		   {
		    TCCR0=0x6d;
		    LCD_write_string(6,0,"   28HZ");
		    break;
		   } //1024分频,F=28HZ
		   case 2:
		   {
		    TCCR0=0x6c;
		    LCD_write_string(6,0,"  112HZ");
		    break; 
		   }// 256分频,F=112HZ
		   case 3:
		   {
		    TCCR0=0x6b;
			LCD_write_string(6,0,"  450HZ");
			break;
		   } //  64分频,F=450HZ
		   case 4:
		   {
		    TCCR0=0x6a;
			LCD_write_string(6,0," 7200HZ");
			break;
		   } //   8分频,F=7200HZ
		   case 5:
		   {
		    TCCR0=0x69;
			LCD_write_string(6,0,"28800HZ");
			break;
		   } //  无分频,F=28800HZ		    
		   default:break;
		  }
 
 
 
}

void R_set(void)
{
 static unsigned char i;
 if(i!=9)i++;
 else i=1;
 switch(i)//频率选择
		  {
		   case 1:
		   {
		    OCR0=0x0a;//占空比10%
		    LCD_write_string(13,0,"10%");
		    break;
		   } 
		   case 2:
		   {
		    OCR0=0x14;//占空比20%
		    LCD_write_string(13,0,"20%");
		    break; 
		   }
		   case 3:
		   {
		    OCR0=0x1e;//占空比30%
			LCD_write_string(13,0,"30%");
			break;
		   } 
		   case 4:
		   {
		    OCR0=0x28;//占空比40%
			LCD_write_string(13,0,"40%");
			break;
		   } 
		   case 5:
		   {
		    OCR0=0x80;//占空比50%
			LCD_write_string(13,0,"50%");
			break;
		   }
		   case 6:
		   {
		    OCR0=0x3c;//占空比60%
			LCD_write_string(13,0,"60%");
			break;
		   } 	
		   case 7:
		   {
		    OCR0=0x46;//占空比70%
			LCD_write_string(13,0,"70%");
			break;
		   } 	
		   case 8:
		   {
		    OCR0=0x50;//占空比80%
			LCD_write_string(13,0,"80%");
			break;
		   } 	
		   case 9:
		   {
		    OCR0=0x5a;//占空比90%
			LCD_write_string(13,0,"90%");
			break;
		   } 		 		    
		   default:break;
		  }

}

void main(void)
{
 uchar key;
 
 LCD_init();//液晶初始化
 init_timer0();
 LCD_write_string(0,0,"F_out:   28HZ50%");
 while(1)
  {
   key=get_key();
   if(key=='A')F_set();
   if(key=='B')R_set();
   
  }
}