ds18b20.c

AVR-based single-chip temperature display system, so absolutely! DS18B20 sensors used

#include <iom16v.h>
#include <macros.h>

#define DQ_IN	DDRA &= ~(1 << PA7)		/*设置输入*/
#define DQ_OUT	DDRA |= (1 << PA7)		/*设置输出*/
#define DQ_CLR	PORTA &= ~(1 << PA7)	/*置低电平*/
#define DQ_SET	PORTA |= (1 << PA7)		/*置高电平*/
#define DQ_R	PINA & (1 << PA7)		/*读了电平*/
unsigned char led_7[] = {0X3f,0X06,0X5B,0X4F,0X66,0X6D,0X7D,0X07,0X7F,0X6F,0x40,0x00,};
unsigned char flag;						/*中断标志缓存*/
unsigned char position[4]={0X07,0X0B,0X0D,0X0E};
//unsigned char time[2];//显示时,分,
unsigned char   dis_buff[4];   // 显示缓冲区    
unsigned char   posit;
unsigned char led_buf[] = {0,0,0,0,};			/*显示信息*/
/*********************delay function********************/
void delay_1us(void)                 //1us延时函数
  {
   asm("nop");
  }

void delay_nus(unsigned int n)       //N us延时函数
  {
   unsigned int i=0;
   for (i=0;i<n;i++)
   delay_1us();
  }
  
void delay_1ms(void)                 //1ms延时函数
  {
   unsigned int i;
   for (i=0;i<1140;i++);
  }
  
void delay_nms(unsigned int n)       //N ms延时函数
  {
   unsigned int i=0;
   for (i=0;i<n;i++)
   delay_1ms();
  }

/*DS18B20复位函数*/
unsigned char ds1820_reset(void) {

	unsigned char i;
	flag = SREG;				/*中断保护*/
	CLI();						/*关中断*/
	DQ_OUT;
	DQ_CLR;
	delay_nus(500);				/*延时500uS(480-960)*/
	DQ_SET;
	DQ_IN;
	delay_nus(80);			/*延时80uS*/
	i = DQ_R;
	delay_nus(490);				/*延时500uS(保持>480uS)*/
	if (flag & 0x80) {			/*恢复中断状态*/
		SEI();
		}
	if (i) {
		return 0x00;
		}
	else {
		return 0x01;
		}
}

/*DS18B20字节读取函数*/
unsigned char ds1820_read_byte(void) {

	unsigned char i;
	unsigned char value = 0;
	flag = SREG;				/*中断保护*/
	CLI();						/*关中断*/
	for (i = 8; i != 0; i--) {
		value >>= 1;
		DQ_OUT;
		DQ_CLR;
		delay_nus(10);
		DQ_SET;
		DQ_IN;
		delay_nus(10);
		if (DQ_R) {
			value|=0x80;
			}
		delay_nus(60);		/*延时60uS*/
		}
	if (flag & 0x80) {			/*恢复中断状态*/
		SEI();
		}
	return(value);
}

/*DS18B20字节写入函数*/
void ds1820_write_byte(unsigned char value) {

	unsigned char i;
	flag = SREG;				/*中断保护*/
	CLI();						/*关中断*/
	for (i = 8; i != 0; i--) {
		DQ_OUT;
		DQ_CLR;
		delay_nus(4);
		if (value & 0x01) {
			DQ_SET;
			}
		delay_nus(80);	/*延时80uS*/
		DQ_SET;					/*位结束*/
		value >>= 1;
		}
	if (flag & 0x80) {			/*恢复中断状态*/
		SEI();
		}
}

/*启动ds1820转换*/
void ds1820_start(void) {

	ds1820_reset();
	ds1820_write_byte(0xCC);	/*勿略地址*/
	ds1820_write_byte(0x44);	/*启动转换*/
}

/*DS8B20读取温度信息*/
unsigned int ds1820_read_temp(void) {

	unsigned int i;
	unsigned char buf[9];

	ds1820_reset();
	ds1820_write_byte(0xCC);	/*勿略地址*/
	ds1820_write_byte(0xBE);	/*读取温度*/
	for (i = 0; i < 9; i++) {
		buf[i] = ds1820_read_byte();
		}
	i = buf[1];
	i <<= 8;
	i |= buf[0];
	
	return i;
}
void time_to_disbuffer(int a,int b,int c,int d)//时间送显示缓冲区函数
{   
  
    dis_buff[0] = a;
    dis_buff[1] =b;
	dis_buff[2] = c;
    dis_buff[3] =d;

}
void display(void)//数码管显示程序
{     PORTD = 0xff;
  PORTC = led_7[dis_buff[posit]];
  PORTD= position[posit];
  if (++posit >=4 ) posit = 0;
} 

// Timer 0 比较匹配中断服务
#pragma interrupt_handler TIMER0_COMP:20 
void TIMER0_COMP(void)
{ 
  display(); 
 
}
  
void main(void)
{
  int i,j;
  PORTD=0xFF;           // 显示控制I/O端口初始化
  DDRD=0xFF;
  PORTC=0XfF;
  DDRC=0xFF;
  

  // 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
  SEI(); //允许全局中断
  
	while (1) {
		ds1820_start();					/*启动一次转换*/
		delay_nms(10);					/*等待转换结束*/
		i=ds1820_read_temp();				/*读取温度数值*/
		if(i>=0xf000)//判断是不是负数
		{
		i=~i;           //转换,先取反,在加1.
		i+=1;
		i = (i * 10) / 16;				/*数值处理*/
		led_buf[3] = i / 1000;			/*将显示信息加载到显示缓存区*/
		i = i % 1000;
		led_buf[2] = i / 100;
		i = i % 100;
		led_buf[1] = i / 10;
		led_buf[0] = i % 10;
		time_to_disbuffer(led_buf[1],led_buf[2],10,11);
		}
		else
		{	
		i = (i * 10) / 16;				/*数值处理*/
		led_buf[3] = i / 1000;			/*将显示信息加载到显示缓存区*/
		i = i % 1000;
		led_buf[2] = i / 100;
		i = i % 100;
		led_buf[1] = i / 10;
		led_buf[0] = i % 10;	
		time_to_disbuffer(led_buf[1],led_buf[2],led_buf[3],led_buf[0]);
		}
		}
}