ds18b20_ph.asm

18B20数字温度

;DS18B20数字温度计

OUTSEG     EQU 0ffdcH   ;字形控制口
OUTBIT     EQU 0ffddH   ;字位/键扫控制口
LedBuf     equ 7eh      ;显示缓冲

TEMPER_L   EQU 	36H     ;存放读出温度低位数据
TEMPER_H   EQU 	35H     ;存放读出温度高位数据
TEMPER_NUM EQU 	60H     ;存放转换后的温度值
FLAG1      BIT	00H
DQ         BIT  P3.3    ;一线总线控制端口

        ORG 0000H
        LJMP MAIN

        ORG 0100H
MAIN:   MOV SP,#70H
        MOV LedBuf-0,#1
        MOV LedBuf-1,#8
        MOV LedBuf-2,#2
        MOV LedBuf-3,#0
        MOV LedBuf-4,#10h
        MOV LedBuf-5,#10h
mloop:  LCALL GET_TEMPER ;从DS18B20读出温度数据
        LCALL TEMPER_COV ;转换读出的温度数据并保存
        mov a,TEMPER_NUM
        mov b,a          ;拆送显示缓冲区
        swap a
        anl a,#0fh
        anl b,#0fh
        MOV LedBuf-4,a
        MOV LedBuf-5,b
        call disp
        SJMP mloop       ;完成一次数字温度采集

;读出转换后的温度值
GET_TEMPER:
        SETB DQ         ;定时入口
BCD:    LCALL INIT_1820
        JB FLAG1,S22
        LJMP BCD        ;若DS18B20不存在则返回
S22:    MOV A,#0CCH     ;跳过ROM匹配------0CC
        LCALL WRITE_1820
        MOV A,#44H      ;发出温度转换命令
        LCALL WRITE_1820
        NOP
CBA:    LCALL INIT_1820
        JB FLAG1,ABC
        LJMP CBA
ABC:    MOV A,#0CCH     ;跳过ROM匹配
        LCALL WRITE_1820
        MOV A,#0BEH     ;发出读温度命令
        LCALL WRITE_1820
        LCALL READ_18200;READ_1820
        RET

;读DS18B20的程序,从DS18B20中读出一个字节的数据
READ_1820:
        MOV R2,#8
RE1:    CLR C
        SETB DQ
        NOP
        NOP
        CLR DQ
        NOP
        NOP
        NOP
        SETB DQ
        MOV R3,#3
        DJNZ R3,$
        MOV C,DQ
        MOV R3,#11
        DJNZ R3,$
        RRC A
        DJNZ R2,RE1
        RET

;写DS18B20的程序
WRITE_1820:
        MOV R2,#8
        CLR C
WR1:    CLR DQ
        MOV R3,#3
        DJNZ R3,$
        RRC A
        MOV DQ,C
        MOV R3,#11
        DJNZ R3,$
        SETB DQ
        NOP
        DJNZ R2,WR1
        SETB DQ
        RET

;读DS18B20的程序,从DS18B20中读出两个字节的温度数据
READ_18200:
        MOV R4,#2       ;将温度高位和低位从DS18B20中读出
        MOV R1,#36H     ;低位存入36H(TEMPER_L),高位存入35H(TEMPER_H)
RE00:   MOV R2,#8
RE01:   CLR C
        SETB DQ
        NOP
        NOP
        CLR DQ
        NOP
        NOP
        NOP
        SETB DQ
        MOV R3,#3
        DJNZ R3,$
        MOV C,DQ
        MOV R3,#11
        DJNZ R3,$
        RRC A
        DJNZ R2,RE01
        MOV @R1,A
        DEC R1
        DJNZ R4,RE00
        RET

;将从DS18B20中读出的温度数据进行转换
TEMPER_COV:
        MOV A,#0F0H
        ANL A,TEMPER_L  ;舍去温度低位中小数点后的四位温度数值
        SWAP A
        MOV TEMPER_NUM,A
        MOV A,TEMPER_L
        JNB ACC.3,TEMPER_COV1 ;四舍五入去温度值
        INC TEMPER_NUM
TEMPER_COV1:
        MOV A,TEMPER_H
        ANL A,#07H
        SWAP A
        ADD A,TEMPER_NUM
        MOV TEMPER_NUM,A ; 保存变换后的温度数据
        LCALL BIN_BCD
        RET

;将16进制的温度数据转换成压缩BCD码
BIN_BCD:MOV DPTR,#TEMP_TAB
        MOV A,TEMPER_NUM
        MOVC A,@A+DPTR
        MOV TEMPER_NUM,A
        RET

TEMP_TAB:
        DB 00H,01H,02H,03H,04H,05H,06H,07H
        DB 08H,09H,10H,11H,12H,13H,14H,15H
        DB 16H,17H,18H,19H,20H,21H,22H,23H
        DB 24H,25H,26H,27H,28H,29H,30H,31H
        DB 32H,33H,34H,35H,36H,37H,38H,39H
        DB 40H,41H,42H,43H,44H,45H,46H,47H
        DB 48H,49H,50H,51H,52H,53H,54H,55H
        DB 56H,57H,58H,59H,60H,61H,62H,63H
        DB 64H,65H,66H,67H,68H,69H,70H,71H
        DB 72H,73H,74H,75H,76H,77H,78H,79H
        DB 80H,81H,82H,83H,84H,85H,86H,87H
        DB 88H,89H,90H,91H,92H,93H,94H,95H
        DB 96H,97H,98H,99H

;DS18B20初始化程序
INIT_1820:
        SETB DQ
        NOP
        CLR DQ
        MOV R0,#40h
TSR1:   DJNZ R0,TSR1    ;延时
        SETB DQ
        MOV R0,#12h     ;96us
TSR2:   DJNZ R0,TSR2
        JNB DQ,TSR3
        LJMP TSR4       ;延时
TSR3:   SETB FLAG1      ;置标志位,表示DS1820存在
        LJMP TSR5
TSR4:   CLR FLAG1       ;清标志位,表示DS1820不存在
        LJMP TSR7
TSR5:   MOV R0,#35h     ;200us
TSR6:   DJNZ R0,TSR6    ;延时
TSR7:   SETB DQ
        RET

;重新写DS18B20暂存存储器设定值
RE_CONFIG:
        JB FLAG1,RE_CONFIG1 ;若DS18B20存在,转RE_CONFIG1
        RET

RE_CONFIG1:
        MOV A,#0CCH     ;发SKIP ROM命令
        LCALL WRITE_1820
        MOV A,#4EH      ;发写暂存存储器命令
        LCALL WRITE_1820
	
        MOV A,#00H      ;TH(报警上限)中写入00H
        LCALL WRITE_1820
        MOV A,#00H      ;TL(报警下限)中写入00H
        LCALL WRITE_1820
        MOV A,#7FH      ;选择12位温度分辨率
        LCALL WRITE_1820
        RET

;=======显示子程序=============
disp:   push dpl
        push dph
        setb rs1
        mov r0,#ledbuf
        mov r2,#20h
        mov dptr,#ledmap
disp2:  mov a,@r0
        movc a,@a+dptr
        push dpl
        push dph
        mov dptr,#outseg
        movx @dptr,a
        mov a,r2
        mov dptr,#outbit
        movx @dptr,a
        pop dph
        pop dpl
        mov r3,#0
        djnz r3,$       ;闪动延迟
        clr c
        rrc a           ;右移显示
        mov r2,a
        dec r0
        jnz disp2
        push acc
        mov dptr,#OUTBIT
        mov a,#0
        movx @dptr,a
        pop acc
        clr rs1
        pop dph
        pop dpl
        ret

;字形表
ledmap: db 0c0h,0f9h,0a4h,0b0h,99h,92h,82h,0f8h
        db 80h,90h,88h,83h,0c6h,0a1h,86h,8eh,0bfh

        END