;=;DS18B20温度计;采用4位LED共阳显示器显示测温值，显示精度0.1，测温范围-55+125;用AT89C51单片机，12MHz晶振;DS1302时钟芯片实现日历年月日时分秒的显示;=常数定义=TIMELEQU 0E0H ;20ms，定时器0时间常数TIMEHEQU 0B1HSECOND EQU 30HMINUTE EQU 31HHOUR EQU 32HDAY EQU 33HMONTH EQU 34HWEEK EQU 35HYEAR EQU 36HTEMPHEAD EQU 38HTEMP_UPPER EQU 2AHTEMP_LOWER EQU 2BH;=工作内存定义=BITST DATA 20HTIME1SOK BIT BITST.1TEMPL DATA 26HTEMPH DATA 27HTEMPHC DATA 28HTEMPLC DATA 29H;= 引脚定义=TEMPDIN BIT P3.7ALARMDIN BIT P1.6RST BIT P1.2CLK BIT P1.1IO BIT P1.0;= 中断向量区=ORG 0000HLJMP STARTORG 000BHLJMP T0IT;=系统初始化=ORG 0100HSTART: MOV SP,#60HCLSMEM: MOV R0,#20HMOV R1,#60HCLSMEM1:MOV R0,#00HINC R0DJNZ R1,CLSMEM1MOV TMOD,#00010001B ;定时器0工作方式1（16BIT）MOV TH0,#TIMEH MOV TL0,#TIMEL ;20msMOV SECOND,#00H MOV MINUTE,#00H MOV HOUR,#14H MOV DAY,#17HMOV MONTH,#01H MOV WEEK,#01H MOV YEAR,#13HMOV TEMP_UPPER,#0AH MOV TEMP_LOWER,#8AHSETB ET0SETBEAMOV PSW,#00H;=;= 主程序=;=LCALL SETDS1302START1: LCALL READ_TEMP;读出温度值子程序LCALL CONVTEMP ;温度BCD码计算处理子程序LCALL REFBCD ;显示区BCD码温度值刷新子程序LCALL GETDS1302SETB TR0LCALL ALARM_JUDGEJNB F0,MAINLCALL ALARM_BEEP MAIN:LCALL DISP_TEMP ;调用显示子程序LCALL DISPLAY_TIME JNB TIME1SOK,MAINCLR TIME1SOK ;测温每1s一次MAIN1:LCALL DISP_TEMP ;调用显示子程序LCALL DISPLAY_DATE JNB TIME1SOK,MAIN1CLR TIME1SOK ;测温每1s一次 LJMP START1;= 定时器0中断服务程序=T0IT:PUSH PSWMOV PSW,#10HMOV TH0,#TIMEHMOV TL0,#TIMELINC R7CJNE R7,#50,T0IT1MOV R7,#00HSETB TIME1SOK ;1s定时到标志T0IT1:POP PSWRETI;=;= 子程序区=;=;=初始化DS18B20=INITDS1820:SETB TEMPDINNOPNOPCLR TEMPDINMOV R6,#0A0H DJNZ R6,$MOV R6,#0A0HDJNZ R6,$SETB TEMPDINMOV R6,#32H DJNZ R6,$MOVR6,#3CHLOOP1820:MOV C,TEMPDINJC INITDS1820OUTDJNZ R6,LOOP1820MOV R6,#064HDJNZ R6,$SJMP INITDS1820INITDS1820OUT:SETB TEMPDINRET;= 读DS18B20的程序，从DS18B20中读出一个字节的数据=READDS1820:MOV R7,#08HSETB TEMPDINNOPNOPREADDS1820LOOP:CLR TEMPDINNOPNOPNOPSETB TEMPDINMOV R6,#07H ;DELAY 15usDJNZ R6,$MOV C,TEMPDINMOV R6,#3CH ;DELAY 120usDJNZ R6,$RRC ASETB TEMPDINDJNZ R7,READDS1820LOOPMOV R6,#3CH ;DELAY 120 usDJNZ R6,$RET;= 写DS18B20的程序，从DS18B20中写一个字节的数据=WRITEDS1820:MOV R7,#08HSETB TEMPDINNOPNOPWRITEDS1820LOP:CLR TEMPDINMOV R6,#07H ;DELAY 15usDJNZ R6,$RRC AMOV TEMPDIN,CMOV R6,#34H ;DELAY 104usDJNZ R6,$SETB TEMPDINDJNZ R7,WRITEDS1820LOPRET;= READ TEMP =READ_TEMP:LCALL INITDS1820MOV A,#0CCHLCALL WRITEDS1820 ;SKIP ROMMOV R6,#34H ;DELAY 104usDJNZ R6,$MOV A,#44HLCALL WRITEDS1820 ;START CONVERSIONMOV R6,#34H ;DELAY 104DJNZ R6,$READTEMP1:LCALLINITDS1820MOV A,#0CCHLCALL WRITEDS1820;SKIP ROMMOV R6,#34H ;DELAY 104usDJNZ R6,$MOV A,#0BEHLCALL WRITEDS1820 ;SCRATCHPADMOV R6,#34H ;DELAY 104usDJNZ R6,$MOV R5,#09HMOV R0,#TEMPHEADMOV B,#00HREADTEMP2:LCALL READDS1820MOV R0,AINC R0DJNZ R5,READTEMP2MOV A,TEMPHEAD+0MOV TEMPL,AMOV A,TEMPHEAD+1MOV TEMPH,AREADTEMPOUT:RET;= 处理温度BCD码子程序=CONVTEMP:MOV A,TEMPHANL A,#80HJZ TEMPC1CLR CMOV A,TEMPLCPL AADD A,#01HMOV TEMPL,AMOV A,TEMPH ;-CPL AADDC A,#00H