D7

D6

D5

D4

D3

D2

D1

D0

1

9

1

9

Ack

by

LM95241

Start by

Master

R/W

Frame 1

Serial Bus Address Byte

Frame 2

Command Byte

Ack

by

LM95241

D7

D6

D5

D4

D3

D2

D1

D0

1

9

Frame 3

Data Byte

Ack by

LM95241

Stop

by

Master

SMBCLK

SMBDAT

SMBCLK

(Continued)

SMBDAT

(Continued)

A5

A3

A2

A0

A6

A4

A1

D7

D6

D5

D4

D3

D2

D1

D0

1

9

1

9

Ack

by

LM95241

Start by

Master

R/W

Frame 1

Serial Bus Address Byte

Frame 2

Command Byte

Ack by

LM95241

SMBCLK

SMBDAT

A5

A3

A2

A0

A6

A4

A1

Stop

by

Master

LM95241

www.ti.com

SNIS143E – AUGUST 2006 – REVISED MARCH 2013

A Write to the LM95241 will always include the address byte and the command byte. A write to any register

requires one data byte.

Reading the LM95241 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 LM95241), 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 LM95241 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). 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 for Access of Data

Figure 8. Serial Bus Write to the Internal Command Register

Figure 9. Serial Bus Write to the internal Command Register followed by a Data Byte

Copyright © 2006–2013, Texas Instruments Incorporated

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