DEL: MOV R5,#02 ;为演示方便,人为插入的延时
DEL01: MOV R6,#200
DEL02: MOV R7,#200
DJNZ R7,$
DJNZ R6,DEL02
DJNZ R5,DEL01
RET
BIN_BCD: MOV B,#10
DIV AB
RET
;---------------------(ds18b20) 访问子程序,时序参见TRANSDATA.PDF文件----------------------------
DS_hart_RST:CLR DS18B20 ;总线复位
MOV R6,#250 ;>DELAY 480US
DJNZ R6,$
setb ds18B20
MOV R6,#40 ;>DELAY 60US
DJNZ R6,$
mov c,dS18B20
MOV R6,#250 ;>DELAY 480US
DJNZ R6,$
setb DS18B20
RET
DS_hart_RD_BYTE: ;读取一字节数据
MOV R5,#08H
RD_HART_BYTE_LP:
NOP
NOP
CLR DS18B20
NOP
NOP
SETB DS18B20
MOV R6,#06
DJNZ R6,$ ;<DELAY 15US
MOV C,DS18B20
RRC A
MOV R6,#40 ;>DELAY 60US
DJNZ R6,$
DJNZ R5,RD_HART_BYTE_LP
RET
DS_HART_WR_BYTE: ;写入一字节指令
MOV R5,#08H
CLR C
WR_HART_BYTE_LP:
nop
nop
CLR DS18B20
NOP
NOP
RRC A
MOV R6,#06
DJNZ R6,$
setb ds18B20
MOV DS18B20,C
MOV R6,#40 ;>DELAY 60US
DJNZ R6,$
SETB DS18B20
DJNZ R5,WR_HART_BYTE_LP
RET | 
