LM83_15 Datasheet, PDF (12/22 Pages) Texas Instruments – Triple-Diode Input and Local Digital Temperature Sensor with Two-Wire Interface

1.0 Functional Description (Continued)
1.9 COMMUNICATING with the LM83
There are 19 data registers in the LM83, selected by the
Command Register. At power-up the Command Register is
set to “00”, the location for the Read Local Temperature Reg-
ister. The Command Register latches the last location it was
set to. Reading the Status Register resets T_CRIT_A and
INT, so long as a temperature comparison does not signal a
fault (see Sections 1.2 and 1.3). All other registers are pre-
defined as read only or write only. Read and write registers
with the same function contain mirrored data.
A Write to the LM83 will always include the address byte and
the command byte. A write to any register requires one data
byte.
Reading the LM83 can take place either of two ways:
1. If the location latched in the Command Register is cor-
rect (most of the time it is expected that the Command
Register will point to one of the Read Temperature Reg-
DS101058-9
isters because that will be the data most frequently read
from the LM83), then the read can simply consist of an
address byte, followed by retrieving the data byte.
2. If the Command Register needs to be set, then an ad-
dress byte, command byte, repeat start, and another ad-
dress byte will accomplish a read.
The data byte has the most significant bit first. At the end of
a read, the LM83 can accept either Acknowledge or No Ac-
knowledge from the Master (No Acknowledge is typically
used as a signal for the slave that the Master has read its
last byte).
1.10 SERIAL INTERFACE ERROR RECOVERY
The LM83 SMBus lines will be reset to the SMBus idle state
if the SMBData or SMBCLK lines are held low for 40 ms or
more (t_TIMEOUT). The LM83 may or may not reset the state of
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