Datasheet
D7 D6 D5 D4 D3 D2 D1 D0
1 9 1 9
Ack
by
LM95214
Start by
Master
R/W
Frame 1
Serial Bus Address Byte
Frame 2
Command Byte
Ack by
LM95214
SMBCLK
SMBDAT
A5 A3
A2
A0
A6 A4
A1
Stop
by
Master
D7 D6 D5 D4 D3 D2 D1 D0
1 9 1 9
Ack
by
LM95214
Start by
Master
R/W
Frame 1
Serial Bus Address Byte
Frame 2
Command Byte
Ack
by
LM95214
D7 D6 D5 D4 D3 D2 D1 D0
1 9
Frame 3
Data Byte
Ack by
LM95214
Stop
by
Master
SMBCLK
SMBDAT
SMBCLK
(Continued)
SMBDAT
(Continued)
A5 A3 A2 A0A6 A4 A1
LM95214
SNIS146A –MARCH 2007–REVISED MARCH 2013
www.ti.com
COMMUNICATING with the LM95214
The data registers in the LM95214 are selected by the Command Register. At power-up the Command Register
is set to “00”, the location for the Read Local Temperature Register. The Command Register latches the last
location it was set to. Each data register in the LM95214 falls into one of three types of user accessibility:
1. Read only
2. Write only
3. Write/Read same address
A Write to the LM95214 will always include the address byte and the command byte. A write to any register
requires one data byte.
Reading the LM95214 can take place either of two ways:
1. If the location latched in the Command Register is correct (most of the time it is expected that the Command
Register will point to one of the Read Temperature Registers because that will be the data most frequently
read from the LM95214), 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 address byte, command byte, repeat start, and another
address byte will accomplish a read.
The data byte has the most significant bit first. At the end of a read, the LM95214 can accept either acknowledge
or No Acknowledge from the Master (No Acknowledge is typically used as a signal for the slave that the Master
has read its last byte). It takes the LM95214 190 ms (typical, all channels enabled) to measure the temperature
of the remote diodes and internal diode. When retrieving all 11 bits from a previous remote diode temperature
measurement, the master must insure that all 11 bits are from the same temperature conversion. This may be
achieved by reading the MSB register first. The LSB will be locked after the MSB is read. The LSB will be
unlocked after being read. If the user reads MSBs consecutively, each time the MSB is read, the LSB associated
with that temperature will be locked in and override the previous LSB value locked-in.
SMBus Timing Diagrams
Figure 17. Serial Bus Write to the internal Command Register followed by a the Data Byte
Figure 18. Serial Bus Write to the Internal Command Register
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