1°C Temperature Sensor with Beta Compensation

Datasheet

SMSC EMC1402

13

Revision 1.16 (03-15-07)

DATASHEET

Chapter 4 System Management Bus Interface Protocol

4.1

System Management Bus Interface Protocol

TheEMC1402 communicates with a host controller, such as an SMSC SIO, through the SMBus. The

SMBus is a two-wire serial communication protocol between a computer host and its peripheral

devices. A detailed timing diagram is shown in Figure 4.1.

.

The EMC1402 is SMBus 2.0 compatible and support Send Byte, Read Byte, Write Byte, Receive Byte,

and the Alert Response Address as valid protocols as shown below.

All of the below protocols use the convention in Table 4.1.

Attempting to communicate with the EMC1402 SMBus interface with an invalid slave address or invalid

protocol will result in no response from the device and will not affect its register contents. Stretching

of the SMCLK signal is supported, provided other devices on the SMBus control the timing.

4.2

Write Byte

The Write Byte is used to write one byte of data to the registers as shown below Table 4.2:

Figure 4.1 SMBus Timing Diagram

Table 4.1 Protocol Format

DATA SENT

TO DEVICE

DATA SENT TO

THE HOST

# of bits sent

# of bits sent

Table 4.2 Write Byte Protocol

START

SLAVE

ADDRESS

WR

ACK

REGISTER

ADDRESS

ACK

REGISTER

DATA

ACK

STOP

1

7

1

181

8

1

1

SMDTA

SMCLK

P

S

S - Start Condition

P - Stop Condition

P

S