Datasheet
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MAX31826
1-Wire Digital Temperature Sensor
with 1Kb Lockable EEPROM
Table 2. MAX31826 Function Command Set
Note 1: For parasite-powered devices, the master must enable a strong pullup on the 1-Wire bus during temperature conversions
and copies from the Scratchpad 2 to EEPROM. No other bus activity can take place during this time.
Note 2: The master can interrupt the transmission of data at any time by issuing a reset.
COMMAND DESCRIPTION PROTOCOL
1-Wire BUS ACTIVITY AFTER COMMAND IS
ISSUED
Convert T
(Note 1)
Initiates temperature conversion. 44h
The device transmits conversion status to master
(not applicable for parasite-powered devices).
Read Scratchpad 1
(Note 2)
Reads the 9-byte scratchpad
including the CRC byte.
BEh
The device transmits up to 9 data bytes to master.
The 9th byte is the CRC byte.
Read Scratchpad 2
(Note 2)
Reads the 9-byte EE scratchpad
including the CRC byte.
AAh
The master transmits the start address. The device
transmits up to 9 data bytes to the master. The 9th
byte is the CRC byte.
Write Scratchpad 2
(Note 2)
Writes to the 8-byte EE
scratchpad.
0Fh
The master transmits the address of first byte in the
target page, and then transmits 8 data bytes. The
device then returns the CRC byte calculated from
the 10 bytes just transmitted.
Copy Scratchpad 2
Writes the contents of the 8-byte
Scratchpad 2 to the EEPROM.
55h
The master transmits token A5h. The device enters
EEPROM write mode, during which communication
is not allowed in parasitic-power mode.
Additionally, a strong pullup is also required during
parasitic-power mode.
Read Memory
(Note 2)
Reads data in the 1Kb user
memory.
F0h
The master transmits the address of first byte to be
read. The device then transmits data starting with
first byte until reaching the end of the available
addresses or until the master issues a reset.
Read Power Supply
Signals the device’s power-supply
mode to the master.
B4h The device transmits supply status to the master.
Lock Low Memory
Prevents further changes to the
lower eight pages of user memory.
—
Write 55h to byte 80h of Scratchpad 2. Copy
Scratchpad 2 to EEPROM.
Lock High Memory
Prevents further changes to the
upper eight pages of user memory.
—
Write 55h to byte 81h of Scratchpad 2. Copy
Scratchpad 2 to EEPROM.