Rainbow Electronics DS1822 - Manual (Page 13)

DS1822
13 of 20
DS1822 FUNCTION COMMANDS FLOW CHART Figure 12
MASTER T X
FUNCTION
COMMAND
Y
N
44h
CONVERT
TEMPERATURE
?
PARASITE
POWER
?
N Y
DS1822 BEGINS
CONVERSION
DEVICE
CONVERTING
TEMPERATURE
?
N
Y
MASTER
R X “0s”
MASTER
R X “1s”
MASTER ENABLES
STRONG PULLUP ON DQ
DS1822 CONVERTS
TEMPERATURE
MASTER DISABLES
STRONG PULLUP
Y
N
48h
COPY
SCRATCHPAD
?
PARASITE
POWER
?
N Y
MASTER ENABLES
STRONG PULL-UP ON DQ
DATA COPIED FROM
SCRATCHPAD TO EEPROM
MASTER DISABLES
STRONG PULLUP
MASTER
R X “0s”
COPY IN
PROGRESS
?
Y
MASTER
R
X
“1s”
N
RETURN TO INITIALIZATION
SEQUENCE (FIGURE 11) FOR
NEXT TRANSACTION
B4h
READ
POWER SUPPLY
?
Y
N
PARASITE
POWERED
?
N
MASTER
R
X
“1s”
MASTER
R
X
“0s”
Y
MASTER T X T H BYTE
TO SCRATCHPAD
Y
N
4Eh
WRITE
SCRATCHPAD
?
MASTER T
X
T
L
BYTE
TO SCRATCHPAD
MASTER T
X
CONFIG. BYTE
TO SCRATCHPAD
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”