Datasheet

Figure 8. MAX31820 Function Commands Flowchart
44h
CONVERT T?
Y
N
PARASITE
POWER?
MASTER T
X
FUNCTION COMMAND
DEVICE BEGINS
CONVERSION
MASTER R
X
“1s”
MASTER R
X
“0s”
YN
MASTER ENABLES
STRONG PULLUP ON DQ
DEVICE CONVERTS
TEMPERATURE
MASTER DISABLES
STRONG PULLUP
MASTER ENABLES
STRONG PULLUP ON DQ
DATA COPIED FROM
SCRATCHPAD TO EEPROM
MASTER DISABLES
STRONG PULLUP
DEVICE
CONVERTING
TEMPERATURE?
Y
N
MASTER R
X
“0s”
MASTER R
X
“1s”
48h
COPY
SCRATCHPAD?
N
PARASITE
POWER?
YN
YN
MASTER T
X
T
H
BYTE
TO SCRATCHPAD
4Eh
WRITE
SCRATCHPAD
?
Y
MASTER T
X
T
L
BYTE
TO SCRATCHPAD
MASTER T
X
CONFIG.
BYTE TO SCRATCHPAD
BEh
READ
SCRATCHPAD
?
Y
Y
MASTER R
X
DATA BYTE
FROM SCRATCHPAD
MASTER BEGINS DATA
RECALL FROM E
2
PROM
RETURN TO INITIALIZATION SEQUENCE
FOR NEXT TRANSACTION
MASTER R
X
SCRATCHPAD
CRC BYTE
Y
N
N
N
MASTER T
X
RESET?
Y
HAVE 8 BYTES
BEEN READ?
B8h
RECALL E
2
?
Y
N
B4h
READ
POWER
SUPPLY?
PARASITE
POWER?
NN
MASTER R
X
“1s”
MASTER R
X
“0s”
COPY
IN PROGRESS?
Y
N
MASTER R
X
“1s”
MASTER R
X
“0s”
DEVICE
BUSY RECALLING
DATA
?
Y
N
MAX31820 1-Wire Ambient Temperature Sensor
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Maxim Integrated │ 15