EMC1422-2-ACZL SMSC, EMC1422-2-ACZL Datasheet - Page 12

• Manufacturer Part Number: EMC1422-2-ACZL
• Description: Board Mount Temperature Sensors DUAL TEMP SNSR
• Manufacturer: SMSC

Specifications of EMC1422-2-ACZL

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Chapter 4 System Management Bus Interface Protocol
.
Revision 1.36 (07-02-09)
4.1
4.2
START
SMCLK
SMDTA
1 -> 0
The EMC1422 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
For the first 15ms after power-up the device may not respond to SMBus communications.
The EMC1422 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
Attempting to communicate with the EMC1422 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.
The Write Byte is used to write one byte of data to the registers as shown below
ADDRESS
System Management Bus Interface Protocol
Write Byte
P
1001_100
SLAVE
T
BUF
S
T
T
S - Start Condition
HD:STA
LOW
WR
0
T
HD:DAT
T
RISE
Figure 4.1 SMBus Timing Diagram
# of bits sent
DATA SENT
ACK
TO DEVICE
Table 4.2 Write Byte Protocol
0
Table 4.1 Protocol Format
T
HIGH
DATASHEET
REGISTER
ADDRESS
T
SU:DAT
XXh
T
12
FALL
DATA SENT TO
# of bits sent
THE HOST
Figure
Table
1°C Temperature Sensor with Hardware Thermal Shutdown
4.1.
4.1.
ACK
0
S
T
T
SU:STA
REGISTER
HD:STA
DATA
XXh
P - Stop Condition
Table
ACK
0
SMSC EMC1422
4.2:
T
SU:STO
Datasheet
0 -> 1
STOP
P