DS1922L Maxim, DS1922L Datasheet - Page 45

• Manufacturer Part Number: DS1922L
• Description: The DS1922L/T temperature logger iButtons® are rugged, self-sufficient systems that measure temperature and record the result in a protected memory section
• Manufacturer: Maxim

ing in the command code, the target addresses TA1
and TA2, and all the data bytes. The DS1922L/DS1922T
transmit this CRC only if the data bytes written to the
scratchpad include scratchpad ending offset 11111b.
The data can start at any location within the scratchpad.
With the Read Scratchpad command, the CRC is gen-
erated by first clearing the CRC generator and then
<Data to EOM>
<Data to EOS>
<Data to EOP>
<PW/Dummy>
<32 Bytes>
SYMBOL
AA Loop
FF Loop
<Data>
CRC-16
TA-E/S
Select
RMC
RST
CPS
STP
FFh
CM
WS
SM
PD
RS
FC
TA
______________________________________________________________________________________
Command-Specific 1-Wire Communication Protocol—Legend
Temperature Logger iButton with 8KB
1-Wire reset pulse generated by master.
1-Wire presence pulse generated by slave.
Command and data to satisfy the ROM function protocol.
Command “Write Scratchpad.”
Command “Read Scratchpad.”
Command “Copy Scratchpad with Password.”
Command “Read Memory with Password and CRC.”
Command “Clear Memory with Password.”
Command “Forced Conversion.”
Command “Start Mission with Password.”
Command “Stop Mission with Password.”
Target Address TA1, TA2.
Target Address TA1, TA2 with E/S byte.
Transfer of as many data bytes as are needed to reach the scratchpad offset 1Fh.
Transfer of as many data bytes as are needed to reach the end of a memory page.
Transfer of as many data bytes as are needed to reach the end of the data-log memory.
Transfer of 8 bytes that either represent a valid password or acceptable dummy data.
Transfer of 32 bytes.
Transfer of an undetermined amount of data.
Transmission of one FFh byte.
Transfer of an inverted CRC-16.
Indefinite loop where the master reads FF bytes.
Indefinite loop where the master reads AA bytes.
shifting in the command code, the target addresses
TA1 and TA2, the E/S byte, and the scratchpad data
starting at the target address. The DS1922L/DS1922T
transmit this CRC only if the reading continues through
the end of the scratchpad, regardless of the actual
ending offset. For more information on generating CRC
values, refer to Application Note 27.
DESCRIPTION
Data-Log Memory
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