Datasheet

DS18S20-PAR
12 of 20
DS18S20-PAR FUNCTION COMMANDS FLOW CHART Figure 10
MASTER T
X
FUNCTION
COMMAND
Y
N
44h
CONVERT
TEMPERATURE
?
MASTER ENABLES
STRONG PULLUP ON DQ
DS18S20-PAR CONVERTS
TEMPERATURE
MASTER DISABLES
STRONG PULLUP
Y
N
48h
COPY
SCRATCHPAD
?
MASTER ENABLES
STRONG PULL-UP ON DQ
DATA COPIED FROM
SCRATCHPAD TO EEPROM
MASTER DISABLES
STRONG PULLUP
RETURN TO INITIALIZATION
SEQUENCE (FIGURE 9) FOR
NEXT TRANSACTION
Y
N
Y
BEh
READ
SCRATCHPAD
?
HAVE 8 BYTES
BEEN READ
?
N
MASTER
T
X
RESET
?
MASTER R
X
DATA BYTE
FROM SCRATCHPAD
N
Y
MASTER R
X
SCRATCHPAD
CRC BYTE
MASTER
R
X
“1s”
Y
N
B8h
RECALL E
2
?
MASTER BEGINS DATA
RECALL FROM E
2
PROM
DEVICE
BUSY RECALLING
DATA
?
N
Y
MASTER
R
X
“0s”
MASTER T
X
T
H
BYTE
TO SCRATCHPAD
Y
N
4Eh
WRITE
SCRATCHPAD
?
MASTER T
X
T
L
BYTE
TO SCRATCHPAD