emc2103-3-kp-tr Standard Microsystems Corp., emc2103-3-kp-tr Datasheet - Page 17

• Manufacturer Part Number: emc2103-3-kp-tr
• Description: Emc2103 Rpm-based Fan Controller With Hardware Thermal Shutdown
• Manufacturer: Standard Microsystems Corp.

RPM-Based Fan Controller with HW Thermal Shutdown
Datasheet
Chapter 4 Communications
SMSC EMC2103
4.1
4.2
SMDATA
START
0 -> 1
SMCLK
The EMC2103 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
however the EMC2103 will not stretch the clock signal.
The EMC2103 contains a single SMBus interface. The EMC2103 client interfaces are SMBus 2.0
compatible and support Send Byte, Read Byte, Receive Byte and the Alert Response Address as valid
protocols. These protocols are used as shown below.
All of the below protocols use the convention in
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
0101_110
P
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
0 -> 1
T
FALL
17
DATA SENT TO
# of bits sent
Figure
THE HOST
Table
4.1. Stretching of the SMCLK signal is supported,
4.1.
ACK
0
S
T
T
SU:STA
HD:STA
REGISTER
DATA
XXh
P - Stop Condition
Revision 0.88 (06-30-08)
Table
ACK
0
T
SU:STO
4.2:
STOP
1 -> 0
P