蓝桥杯之单片机设计与开发（35）——2018_第九届_蓝桥杯_国赛——“多功能测量仪表”

秒速五厘米 2022-02-03 19:27 429阅读 0赞

既然进了国赛就稍微准备一下吧。

趁着每天晚上一个小时闲暇时刻写的程序。

总之来说，第九届国赛题不难，长按键我倒是想了几分钟。

# 1、题目 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1hpYW9tb19oYWE_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1hpYW9tb19oYWE_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1hpYW9tb19oYWE_size_16_color_FFFFFF_t_70 2][]

# 2、代码 #

好像代码里面有注释的，应该可以看懂，就不写什么了。

main.c

#include <stc15.h>
    #include "sys.h"
    
    bit flag_5ms = 0, flag_200ms = 0, flag_500ms = 0, flag_1s = 0;
    bit flag_keep = 0;
    bit flag_HShow = 0;
    bit flag_S6_Press = 0, flag_S6_LongPress = 0;
    u8 mode = 3;
    u16 Fre = 0, Temper_int = 0, Temper_dec = 0;
    u16 H_Fre = 0, H_Temper_int = 0, H_Temper_dec = 0;
    u8 Vol = 0, VTH = 20;
    u8 H_Vol = 0;
    u16 counter = 0;
    
    void main(void)
    {
    	static u8 E2_index = 1;
    	
    	AllInit();
    	Check_data();
    	init_ds18b20();
    	Trans_temper();
    	Timer0Init();
    	Timer1Init();
    	
    	EA = 1;
    	while(1)
    	{
    		//RB2电压测量程序
    		if(flag_200ms)			//200ms测量一次电压
    		{
    			flag_200ms = 0;
    			Vol = Read_AIN(0x03);		//读取RB2电压
    		}
    		
    		//频率测量程序
    		if(flag_500ms)
    		{
    			flag_500ms = 0;
    			TR0 = 0;		//关闭定时器0
    			counter = TH0 * 256 + TL0;
    			Fre = counter * 2;
    			TH0 = TL0 = 0;
    			TR0 = 1;
    		}
    		
    		//温度测量程序
    		if(flag_1s)
    		{
    			flag_1s = 0;
    			Temper_int = Gettemper();
    			Temper_dec = Temper_int & 0xf;		//分离小数部分
    			Temper_dec = Temper_dec * ((10000 / 16) / 100);
    			Temper_int = Temper_int >> 4;			//分离整数部分
    			
    			Trans_temper();								//启动下一次温度转换
    		}
    		
    		//数据保存程序
    		if(flag_keep)
    		{
    			if(flag_5ms)
    			{
    				flag_5ms = 0;
    				switch(E2_index)
    				{
    					case 1: Write_E2PROM(0x00, 0x16); break;		//写入标志
    					case 2: Write_E2PROM(0x01, H_Fre >> 8); break;					//写入频率的高八位
    					case 3: Write_E2PROM(0x02, H_Fre & 0xff); break;				//写入频率的低八位
    					case 4: Write_E2PROM(0x03, H_Temper_int >> 8); break;		//写入温度整数部分高八位
    					case 5: Write_E2PROM(0x04, H_Temper_int & 0xff); break;	//写入温度整数部分低八位
    					case 6: Write_E2PROM(0x05, H_Temper_dec >> 8); break;		//写入温度小数部分高八位
    					case 7: Write_E2PROM(0x06, H_Temper_dec & 0xff); break;	//写入温度小数部分低八位
    					case 8: Write_E2PROM(0x07, H_Vol); E2_index = 0; flag_keep = 0; break;	//写入电压值并结束写E2PROM
    				}
    				E2_index ++;
    			}
    		}
    		
    		KeyPress();
    	}
    }

sys.c

#include "sys.h"
    
    void Delay5ms()		//@12.000MHz
    {
    	unsigned char i, j;
    
    	i = 59;
    	j = 90;
    	do
    	{
    		while (--j);
    	} while (--i);
    }
    
    void Check_data(void)
    {
    	if(Read_E2PROM(0x00) == 0x16)
    	{
    		H_Fre = ((u16)(Read_E2PROM(0x01) << 8)) | (Read_E2PROM(0x02));
    		H_Temper_int = ((u16)(Read_E2PROM(0x03) << 8)) | (Read_E2PROM(0x04));
    		H_Temper_dec = ((u16)(Read_E2PROM(0x05) << 8)) | (Read_E2PROM(0x06));
    		H_Vol = Read_E2PROM(0x07);
    	}
    	else
    	{
    		 Write_E2PROM(0x00, 0x16); Delay5ms();
    		 Write_E2PROM(0x01, 0); Delay5ms();
    		 Write_E2PROM(0x02, 0); Delay5ms();
    		 Write_E2PROM(0x03, 0); Delay5ms();
    		 Write_E2PROM(0x04, 0); Delay5ms();
    		 Write_E2PROM(0x05, 0); Delay5ms();
    		 Write_E2PROM(0x06, 0); Delay5ms();
    		 Write_E2PROM(0x07, 0);
    	}
    }
    
    void AllInit(void)
    {
    	P2 = (P2 & 0x1f) | 0x80;
    	P0 = 0xff;
    	P2 = (P2 & 0x1f) | 0xc0;
    	P0 = 0x00;
    	P2 = (P2 & 0x1f) | 0xa0;
    	P0 = 0x00;
    	P2 = P2 & 0x1f;
    }
    
    void Timer0Init(void)
    {
    	AUXR &= 0x7F;							//定时器时钟12T模式
      TMOD = 0x04;                    //设置定时器0为16位自动重装载外部记数模式
      TH0 = TL0 = 0x00;               //设置定时器0初始值
      TR0 = 1;                        //定时器0开始工作
      ET0 = 1;                        //开定时器0中断
    }
    
    void Timer1Init(void)		//1毫秒@12.000MHz
    {
    	AUXR |= 0x40;		//定时器时钟1T模式
    	TMOD &= 0x0F;		//设置定时器模式
    	TL1 = 0x20;		//设置定时初值
    	TH1 = 0xD1;		//设置定时初值
    	TF1 = 0;		//清除TF1标志
    	TR1 = 1;		//定时器1开始计时
    	ET1 = 1;
    }
    
    void Timer1(void) interrupt 3
    {
    	static u16 t00 = 0, t01 = 0, t03 = 0;
    	static u8 t02 = 0;
    	static u8 leddat = 0;
    	static bit temp = 1;
    	u8 ledtemp;
    	
    	t00 ++; t01 ++; t02 ++;
    	
    	if(flag_keep)
    	{
    		if(t02 % 5 == 0)
    			flag_5ms = 1;
    	}
    	
    	if(t02 >= 200)
    	{
    		t02 = 0;
    		flag_200ms = 1;
    		
    		if(Vol > VTH)
    			temp = ~temp;		//实现L8闪烁
    	}
    	if(t01 >= 500)
    	{
    		t01 = 0;
    		flag_500ms = 1;
    	}
    	if(t00 >= 1000)
    	{
    		t00 = 0;
    		flag_1s = 1;
    	}
    	
    	//S6长按键800ms检测程序
    	if(flag_S6_Press)
    	{
    		t03 ++;
    		if(t03 >= 800)
    		{
    			t03 = 0;
    			flag_S6_LongPress = 1;
    		}
    		if(flag_S6_LongPress)
    		{
    			if(t03 >= 100)
    			{
    				t03 = 0;
    				VTH += 1;
    				if(VTH > 50)
    					VTH = 1;
    			}
    		}
    	}
    	else
    	{
    		t03 = 0;
    		flag_S6_LongPress = 0;
    	}
    	
    	if(mode == 3)				//温度测量 L1亮
    		leddat = 0xfe;
    	else if(mode == 2)	//频率测量 L2亮
    		leddat = 0xfd;
    	else if(mode == 1)	//电压测量 L3亮
    		leddat = 0xfb;
    	else
    		leddat = 0xff;
    	
    	//实现L8闪烁程序
    	if(mode != 4)
    	{
    		if(Vol > VTH)
    		{
    			ledtemp = (u8)temp << 7;
    			ledtemp = 0xff - ledtemp;
    			leddat &= ledtemp;
    		}
    	}
    	
    	KeyScan();
    	TubeShow();
    	TubeScan();
    	LedWork(leddat);	
    }

sys.h

#ifndef _SYS_H_
    #define _SYS_H_
    
    typedef unsigned char u8;
    typedef unsigned int u16;
    typedef unsigned long u32;
    
    #include <stc15.h>
    #include <intrins.h>
    #include "ds18b20.h"
    #include "iic.h"
    
    extern bit flag_5ms, flag_200ms, flag_500ms, flag_1s;	//5ms-keep 200ms-U 500ms-F 1s-T
    extern bit flag_keep;
    extern bit flag_HShow;		//回显标志
    extern bit flag_S6_Press, flag_S6_LongPress;	//S6长按键功能标志
    extern u8 mode;						//0-OFF 1-U 2-F 3-T 4-P 5-HU 6-HF 7-HT
    extern u16 Fre, Temper_int, Temper_dec;		//F T
    extern u16 H_Fre, H_Temper_int, H_Temper_dec;		//H_F H_T
    extern u8 Vol, VTH;				//U P
    extern u8 H_Vol;				//H_U
    
    void Check_data(void);
    void AllInit(void);
    void Timer0Init(void);
    void Timer1Init(void);
    
    void TubeScan(void);
    void TubeShow(void);
    void LedWork(u8 leddat);
    
    void KeyScan(void);
    void KeyPress(void);
    void KeyAction(u8 keycode);
    
    
    
    #endif

key.c

#include "sys.h"
    
    sbit KeyOut1 = P4^4;
    sbit KeyOut2 = P4^2;
    sbit KeyOut3 = P3^5;
    sbit KeyOut4 = P3^4;
    sbit KeyIn1 = P3^0;
    sbit KeyIn2 = P3^1;
    sbit KeyIn3 = P3^2;
    sbit KeyIn4 = P3^3;
    
    unsigned char code KeyMap[4][4] = {
       {1, 2, 3, 4}, 
    																	 {5, 6, 7, 8}, 
    																	 {9, 10, 11, 12}, 
    																	 {13, 14, 15, 16}};
    unsigned char KeyBuff[4][4] = {
       {0xff, 0xff, 0xff, 0xff},
    															 {0xff, 0xff, 0xff, 0xff}, 
    															 {0xff, 0xff, 0xff, 0xff}, 
    															 {0xff, 0xff, 0xff, 0xff}};
    unsigned char KeySta[4][4] = {
       {1,1,1,1},{1,1,1,1},{1,1,1,1},{1,1,1,1}};
    unsigned char KeyBackup[4][4] = {
       {1,1,1,1}, {1,1,1,1}, {1,1,1,1}, {1,1,1,1}};
    	
    void KeyScan(void)
    {
    	static u8 index = 0;
    	u8 i;
    	
    	//获取当前键值
    	KeyBuff[0][index] = (KeyBuff[0][index] << 1) | KeyIn1;
    	KeyBuff[1][index] = (KeyBuff[1][index] << 1) | KeyIn2;
    	KeyBuff[2][index] = (KeyBuff[2][index] << 1) | KeyIn3;
    	KeyBuff[3][index] = (KeyBuff[3][index] << 1) | KeyIn4;
    
    	for(i = 0; i < 4; i ++)
    	{
    		if((KeyBuff[i][index] & 0x0f) == 0x00)
    			KeySta[i][index] = 0;
    		else if((KeyBuff[i][index] & 0x0f) == 0x0f)
    			KeySta[i][index] = 1;
    		else
    		{
    			//当S6按下后，一旦发生按键松动，则不是长按键状态
    			if(flag_S6_Press)
    				flag_S6_Press = 0;
    		}
    	}
    	
    	index ++;
    	index &= 0x03;
    	switch(index)
    	{
    		case 0: KeyOut1 = 0; KeyOut4 = 1; break;
    		case 1: KeyOut2 = 0; KeyOut1 = 1; break;
    		case 2: KeyOut3 = 0; KeyOut2 = 1; break;
    		case 3: KeyOut4 = 0; KeyOut3 = 1; break;
    	}
    }
    
    void KeyPress(void)
    {
    	u8 i, j;
    	
    	for(i = 0; i < 4; i ++)
    	{
    		for(j = 0; j < 4; j ++)
    		{
    			if(KeyBackup[i][j] != KeySta[i][j])
    			{
    				if(KeySta[i][j] == 0)        //按键按下时操作
    					KeyAction(KeyMap[i][j]);
    				KeyBackup[i][j] = KeySta[i][j];
    			}
    		}
    	}
    }
    
    void KeyAction(u8 keycode)
    {
    	static u8 mode_backup;
    	
    	if(keycode == 13)		//S4 切换显示
    	{
    		mode ++;
    		if(!flag_HShow)		//关闭回显模式
    		{
    			if(mode == 4)
    				mode = 1;
    		}
    		else
    		{
    			if(mode == 8)
    				mode = 5;
    		}
    	}
    	else if(keycode == 9)		//S5 备份数据存储数据
    	{
    		if((!flag_HShow) && (mode != 4))
    		{
    			if(!flag_keep)
    			{
    				//备份当前数据
    				H_Fre = Fre;
    				H_Temper_int = Temper_int;
    				H_Temper_dec = Temper_dec;
    				H_Vol = Vol;
    				flag_keep = 1;
    			}
    		}
    	}
    	
    	else if(keycode == 5)		//S6 回显/阈值+
    	{
    		if(mode != 4)				//非设置界面
    		{
    			if(flag_HShow)		//关闭回显模式
    			{
    				flag_HShow = 0;
    				mode = mode_backup;
    			}
    			else
    			{
    				flag_HShow = 1;
    				mode_backup = mode;
    				mode = 5;
    			}
    		}
    		else if(mode == 4)		//设置界面
    		{
    			VTH += 1;
    			flag_S6_Press = 1;
    			if(VTH > 50)
    				VTH = 1;
    		}
    	}
    	
    	else if(keycode == 1)	//S7
    	{
    		if(mode != 4)				//在非设置界面按下
    		{
    			mode_backup = mode;
    			mode = 4;
    		}
    		else if(mode == 4)	//在设置界面按下
    		{
    			mode = mode_backup;
    		}
    	}
    }

display.c

#include "sys.h"
    
    unsigned char code table[]={0xc0, 0xf9, 0xa4, 0xb0, 0x99, 0x92, 0x82, 0xf8, 
                                0x80, 0x90, 0x88, 0x83, 0xc6, 0xa1, 0x86, 0x8e,
    														0xff, 0xbf, 0xc1, 0x89, 0x8c};	//18-U 19-H 20-P
    unsigned char TubeBuff[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
    unsigned char smg1, smg2, smg3, smg4, smg5, smg6, smg7, smg8;
    
    void TubeScan(void)
    {
    	static u8 index = 0;
    	
    	P0 = 0x00;
    	P2 = (P2 & 0x1f) | 0xc0;
    	P0 = 0x01 << index;
    	P2 = P2 & 0x1f;
    	
    	P0 = 0xff;
    	P2 = (P2 & 0x1f) | 0xe0;
    	P0 = TubeBuff[index];
    	P2 = P2 & 0x1f;
    	
    	index ++;
    	index &= 0x07;
    }
    
    void TubeShow(void)
    {
    	//mode == 1 显示RB2电压
    	if(mode == 1)
    	{
    		smg1 = 18;	//U
    		smg2 = smg3 = smg4 = smg5 = smg6 = 16;
    		smg7 = Vol / 10;
    		smg8 = Vol % 10;
    	}
    	
    	//mode == 2 显示频率
    	else if(mode == 2)
    	{
    		smg1 = 15;	//F
    		smg2 = smg3 = 16;
    		smg4 = Fre / 10000;
    		smg5 = (Fre % 10000) / 1000;
    		smg6 = (Fre % 1000) / 100;
    		smg7 = (Fre % 100) / 10;
    		smg8 = Fre % 10;
    		
    		if(smg4 == 0)
    		{
    			smg4 = 16;
    			if(smg5 == 0)
    			{
    				smg5 = 16;
    				if(smg6 == 0)
    				{
    					smg6 = 16;
    					if(smg7 == 0)
    						smg7 = 16;
    				}
    			}
    		}
    	}
    	
    	//mode == 3 显示温度
    	else if(mode == 3)
    	{
    		smg1 = 12;		//T
    		smg2 = smg3 = smg4 = 16;
    		smg5 = Temper_int / 10;
    		smg6 = Temper_int % 10;
    		smg7 = Temper_dec / 10;
    		smg8 = Temper_dec % 10;
    		
    		if(smg5 == 0)
    			smg5 = 16;
    	}
    	
    	//mode == 4 显示阈值设置
    	else if(mode == 4)
    	{
    		smg1 = 20;
    		smg2 = smg3 = smg4 = smg5 = smg6 = 16;
    		smg7 = VTH / 10;
    		smg8 = VTH % 10;
    	}
    
    	//mode == 5 回显RB2电压
    	else if(mode == 5)
    	{
    		smg1 = 19;	//H
    		smg2 = 18;	//U
    		smg3 = smg4 = smg5 = smg6 = 16;
    		smg7 = H_Vol / 10;
    		smg8 = H_Vol % 10;
    	}
    	
    	//mode == 6 回显频率
    	else if(mode == 6)
    	{
    		smg1 = 19;	//H
    		smg2 = 15;	//F
    		smg3 = 16;
    		smg4 = H_Fre / 10000;
    		smg5 = (H_Fre % 10000) / 1000;
    		smg6 = (H_Fre % 1000) / 100;
    		smg7 = (H_Fre % 100) / 10;
    		smg8 = H_Fre % 10;
    		
    		if(smg4 == 0)
    		{
    			smg4 = 16;
    			if(smg5 == 0)
    			{
    				smg5 = 16;
    				if(smg6 == 0)
    				{
    					smg6 = 16;
    					if(smg7 == 0)
    						smg7 = 16;
    				}
    			}
    		}
    	}
    	
    	//mode == 7 回显温度
    	else if(mode == 7)
    	{
    		smg1 = 19;	//H
    		smg2 = 12;	//T
    		smg3 = smg4 = 16;
    		smg5 = H_Temper_int / 10;
    		smg6 = H_Temper_int % 10;
    		smg7 = H_Temper_dec / 10;
    		smg8 = H_Temper_dec % 10;
    		
    		if(smg5 == 0)
    			smg5 = 16;
    	}
    	
    	TubeBuff[0] = table[smg1];
    	TubeBuff[1] = table[smg2];
    	TubeBuff[2] = table[smg3];
    	TubeBuff[3] = table[smg4];
    	TubeBuff[4] = table[smg5];
    	TubeBuff[5] = table[smg6];
    	TubeBuff[6] = table[smg7];
    	TubeBuff[7] = table[smg8];
    	
    	//添加小数点
    	if((mode == 1) || (mode == 5) || (mode == 4))
    		TubeBuff[6] &= 0x7f;
    	else if((mode == 3) || (mode == 7))
    		TubeBuff[5] &= 0x7f;
    }
    
    void LedWork(u8 leddat)
    {
    	P0 = 0xff;
    	P2 = (P2 & 0x1f) | 0x80;
    	P0 = leddat;
    	P2 = P2 & 0x1f;
    }

iic.c

#include "sys.h"
    
    #define somenop {_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();}    
    
    //总线引脚定义
    sbit SDA = P2^1;  /* 数据线 */
    sbit SCL = P2^0;  /* 时钟线 */
    
    
    //总线启动条件
    void IIC_Start(void)
    {
    	SDA = 1;
    	SCL = 1;
    	somenop;
    	SDA = 0;
    	somenop;
    	SCL = 0;	
    }
    
    //总线停止条件
    void IIC_Stop(void)
    {
    	SDA = 0;
    	SCL = 1;
    	somenop;
    	SDA = 1;
    }
    
    //应答位控制
    void IIC_Ack(bit ackbit)
    {
    	if(ackbit) 
    	{	
    		SDA = 0;
    	}
    	else 
    	{
    		SDA = 1;
    	}
    	somenop;
    	SCL = 1;
    	somenop;
    	SCL = 0;
    	SDA = 1; 
    	somenop;
    }
    
    //等待应答
    bit IIC_WaitAck(void)
    {
    	SDA = 1;
    	somenop;
    	SCL = 1;
    	somenop;
    	if(SDA)    
    	{   
    		SCL = 0;
    		IIC_Stop();
    		return 0;
    	}
    	else  
    	{ 
    		SCL = 0;
    		return 1;
    	}
    }
    
    //通过I2C总线发送数据
    void IIC_SendByte(unsigned char byt)
    {
    	unsigned char i;
    	for(i=0;i<8;i++)
    	{   
    		if(byt&0x80) 
    		{	
    			SDA = 1;
    		}
    		else 
    		{
    			SDA = 0;
    		}
    		somenop;
    		SCL = 1;
    		byt <<= 1;
    		somenop;
    		SCL = 0;
    	}
    }
    
    //从I2C总线上接收数据
    unsigned char IIC_RecByte(void)
    {
    	unsigned char da;
    	unsigned char i;
    	
    	for(i=0;i<8;i++)
    	{   
    		SCL = 1;
    		somenop;
    		da <<= 1;
    		if(SDA) 
    		da |= 0x01;
    		SCL = 0;
    		somenop;
    	}
    	return da;
    }
    
    unsigned char Read_AIN(unsigned char chn)
    {
    	unsigned char val;
    	unsigned char dat;
    	EA = 0;
    	IIC_Start();						//IIC总线起始信号							
    	IIC_SendByte(0x90);			//PCF8591的写设备地址		
    	IIC_WaitAck();  		    //等待从机应答		
    	IIC_SendByte(chn); 			//写入PCF8591的控制字节		
    	IIC_WaitAck();  				//等待从机应答						
    	IIC_Stop(); 						//IIC总线停止信号					
    	
    	IIC_Start();						//IIC总线起始信号									
    	IIC_SendByte(0x91); 	  //PCF8591的读设备地址		
    	IIC_WaitAck(); 			    //等待从机应答		
    	dat = IIC_RecByte();	  //读取PCF8591通道chn的数据 			
    	IIC_Ack(0); 						//产生非应答信号				
    	IIC_Stop(); 						//IIC总线停止信号		
    	val = (u8)(((u16)dat * (50000 / 255)) / 1000);
    	EA = 1;
    	
    	return val;	
    }
    
    
    void Write_E2PROM(unsigned char add, unsigned char dat)
    {
    	EA = 0;
      IIC_Start();
      IIC_SendByte(0xa0);	//发送器件地址
      IIC_WaitAck();
      IIC_SendByte(add);	//发送操作地址
      IIC_WaitAck();
      IIC_SendByte(dat);	//写一字节
      IIC_WaitAck();
      IIC_Stop();
      somenop;
    	EA = 1;
    }
    
    unsigned char Read_E2PROM(unsigned char add)
    {
      unsigned char d;
    	
    	IIC_Start();
    	IIC_SendByte(0xa0); 	//发送器件地址
    	IIC_WaitAck();
    	IIC_SendByte(add);		//发送要操作的地址
    	IIC_WaitAck();
    	IIC_Stop();
    	
    	IIC_Start();
    	IIC_SendByte(0xa1);		//发送读操作
    	IIC_WaitAck();
    	d = IIC_RecByte();	//读一字节
    	IIC_Ack(0);
    	IIC_Stop();
    	return d;
    }

iic.h

#ifndef _IIC_H
    #define _IIC_H
    
    //函数声明
    void IIC_Start(void); 
    void IIC_Stop(void);  
    void IIC_Ack(bit ackbit); 
    void IIC_SendByte(unsigned char byt); 
    bit IIC_WaitAck(void);  
    unsigned char IIC_RecByte(void); 
    unsigned char Read_AIN(unsigned char chn);
    void Write_E2PROM(unsigned char add, unsigned char dat);
    unsigned char Read_E2PROM(unsigned char add);
    
    #endif

ds18b20.c

#include "sys.h"
    
    sbit DQ = P1^4;  //单总线接口
    
    //单总线延时函数
    void Delay_OneWire(unsigned int t)  
    {
    	unsigned char i;
    	while(t--){
    		for(i=0; i<8; i++);
    	}
    }
    
    
    //通过单总线向DS18B20写一个字节
    void Write_DS18B20(unsigned char dat)
    {
    	unsigned char i;
    	for(i=0;i<8;i++)
    	{
    		DQ = 0;
    		DQ = dat&0x01;
    		Delay_OneWire(5);
    		DQ = 1;
    		dat >>= 1;
    	}
    	Delay_OneWire(5);
    }
    
    //从DS18B20读取一个字节
    unsigned char Read_DS18B20(void)
    {
    	unsigned char i;
    	unsigned char dat;
      
    	for(i=0;i<8;i++)
    	{
    		DQ = 0;
    		dat >>= 1;
    		DQ = 1;
    		if(DQ)
    		{
    			dat |= 0x80;
    		}	    
    		Delay_OneWire(5);
    	}
    	return dat;
    }
    
    //DS18B20设备初始化
    bit init_ds18b20(void)
    {
      	bit initflag = 0;
      	
      	DQ = 1;
      	Delay_OneWire(12);
      	DQ = 0;
      	Delay_OneWire(80);
      	DQ = 1;
      	Delay_OneWire(10); 
        	initflag = DQ;     
      	Delay_OneWire(5);
      
      	return initflag;
    }
    
    //开始温度转换
    void Trans_temper()
    {	
    	init_ds18b20();					//初始化
    	Write_DS18B20(0xcc);		//跳过ROM,因为只有一个DS18B20
    	Write_DS18B20(0x44);		//启动温度转换
    }
    
    //读取温度
    int Gettemper()
    {
    	unsigned char higt, low;	//定义高八位低八位
    	unsigned int temper;			//温度值
    	
    	init_ds18b20();					//初始化
    	Write_DS18B20(0xcc);		//跳过ROM,因为只有一个DS18B20
    	Write_DS18B20(0xbe);
    	
    	low = Read_DS18B20();
    	higt = Read_DS18B20();
    	temper = ((unsigned int)higt << 8) | low;
    	
    	return temper;
    }

ds18b20.h

#ifndef __DS18B20_H
    #define __DS18B20_H
    
    //单总线延时函数
    void Delay_OneWire(unsigned int t);
    void Write_DS18B20(unsigned char dat);
    unsigned char Read_DS18B20(void);
    bit init_ds18b20(void);
    void Trans_temper();
    int Gettemper();
    
    #endif

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