Hi, 1 wire family is communication that sensitive with the timing. so you can't interrupt while execute the device. I put some subroutine and example for DS1820, but I skip reading & check CRC. You could add CRC table if needed.
Hope this can helpfull.

Suhandry Salim


RDTEMP: ACALL INIT1W ;Init 1Wire
JB OWERROR,ERROR ;Check if Error
MOV A,#0CCH
ACALL WRBYTE1W ;Skip ROM
MOV A,#44H
ACALL WRBYTE1W ;Do Temp Measure

LCALL PAUSE500MS ;Give a Time

ACALL INIT1W ;Init 1Wire
JB OWERROR,ERROR
MOV A,#0CCH
ACALL WRBYTE1W ;Skip ROM
MOV A,#0BEH
ACALL WRBYTE1W ;BEH = Read DATA
ACALL RDBYTE1W ;Get LSB
"save LSB in RAM"
ACALL RDBYTE1W ;Get MSB
"save MSB in RAM"
RET

ERROR: "do something" ; need do something if error
RET
;-------------------------------------------------

;-------------------------------------------------
;Initialize 1-Wire Device
;Input : None
;Output: 1WERROR Flag -> 1 If No Device / Error
;-------------------------------------------------
INIT1W: CLR OWERROR
CLR DQ
LCALL PAUSE500US
SETB DQ
LCALL PAUSE65US
JNB DQ,OWVALID
SETB OWERROR
OWVALID: LCALL PAUSE500US
RET

;--------------------------------------------------
;Write 1 Byte to 1-Wire Device
;Input : A = Data / Command
;Output: None
;--------------------------------------------------
WRBYTE1W: PUSH 07H
MOV R7,#8
OWWRNxtBit: CLR DQ
RRC A
MOV DQ,C
JNC OWLBit
SETB DQ
OWLbit: LCALL PAUSE65US
SETB DQ
DJNZ R7,OWWRNxtBit
POP 07H
RET

;--------------------------------------------------
;Read 1 Byte From 1-Wire Device's Register
;Input : None
;Output: A = Data / Status
;--------------------------------------------------
RDByte1W: PUSH 07H
MOV R7,#8
OWRDNxtBit: CLR DQ
NOP
NOP
NOP
SETB DQ
LCALL PAUSE10US
MOV C,DQ
RRC A
LCALL PAUSE65US
DJNZ R7,OWRDNxtBit
SETB DQ
POP 07H
RET