Datasheet

DS1922L/DS1922T
Temperature Logger iButton with 8KB
Data-Log Memory
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AVAILABLE COMMANDS: DATA FIELD AFFECTED:
READ ROM
MATCH ROM
SEARCH ROM
CONDITIONAL SEARCH ROM
SKIP ROM
RESUME
OVERDRIVE-SKIP ROM
OVERDRIVE-MATCH ROM
64-BIT ROM, RC-FLAG
64-BIT ROM, RC-FLAG
64-BIT ROM, RC-FLAG
64-BIT ROM, RC-FLAG, ALARM FLAGS, SEARCH CONDITIONS
RC-FLAG
RC-FLAG
RC-FLAG, OD-FLAG
64-BIT ROM, RC-FLAG, OD-FLAG
1-Wire ROM
FUNCTION COMMANDS
WRITE SCRATCHPAD
READ SCRATCHPAD
COPY SCRATCHPAD WITH PW
READ MEMORY WITH PW AND CRC
CLEAR MEMORY WITH PW
FORCED CONVERSION
START MISSION WITH PW
STOP MISSION WITH PW
256-BIT SCRATCHPAD, FLAGS
256-BIT SCRATCHPAD
512-BYTE DATA MEMORY, REGISTERS, FLAGS, PASSWORDS
MEMORY, REGISTERS, PASSWORDS
MISSION TIMESTAMP, MISSION SAMPLES COUNTER,
START DELAY, ALARM FLAGS, PASSWORDS
MEMORY ADDRESSES 020Ch TO 020Dh
FLAGS, TIMESTAMP, MEMORY ADDRESSES
020Ch TO 020Dh (WHEN LOGGING)
FLAGS
DS1922L/DS1922T-SPECIFIC
MEMORY/CONTROL FUNCTION
COMMANDS
COMMAND LEVEL:
BUS
MASTER
1-Wire NET
OTHER DEVICES
DS1922L/DS1922T
Figure 2. Hierarchical Structure for 1-Wire Protocol
MSB
8-BIT
CRC CODE
48-BIT SERIAL NUMBER
MSB MSBLSB
LSB
LSB
8-BIT FAMILY CODE
(41h)
MSBLSB
Figure 3. 64-Bit Lasered ROM
1ST
STAGE
2ND
STAGE
3RD
STAGE
4TH
STAGE
7TH
STAGE
8TH
STAGE
6TH
STAGE
5TH
STAGE
X
0
X
1
X
2
X
3
X
4
POLYNOMIAL = X
8
+ X
5
+ X
4
+ 1
INPUT DATA
X
5
X
6
X
7
X
8
Figure 4. 1-Wire CRC Generator