emc2101 Standard Microsystems Corp., emc2101 Datasheet - Page 14

• Manufacturer Part Number: emc2101
• Description: Emc2101 Fan Control With 1?c Accurate Temperature Monitoring
• Manufacturer: Standard Microsystems Corp.

Chapter 4 System Management Bus Interface Protocol
Revision 2.53 (02-19-08)
4.1
4.2
SMCLK
SMDTA
START
1
P
The EMC2101 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 EMC2101 will not stretch the clock signal.
The EMC2101 powers up as an SMBus client (after loading from EEPROM as applicable).
The EMC2101 is SMBus 2.0 compatible and supports Send Byte, Read Byte, Receive Byte and the
Alert Response Address as valid protocols 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
SLAVE
T
BUF
7
S
T
T
S - Start Condition
HD:STA
LOW
WR
1
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
1
Table 4.1 Protocol Format
T
HIGH
DATASHEET
T
REGISTER
SU:DAT
ADDRESS
T
FALL
14
8
DATA SENT TO
# of bits sent
Figure
SMBus Fan Control with 1°C Accurate Temperature Monitoring
THE HOST
Table
4.1. Stretching of the SMCLK signal is supported,
4.1.
ACK
1
S
T
T
SU:STA
HD:STA
REGISTER
DATA
8
P - Stop Condition
Table
ACK
1
T
SU:STO
SMSC EMC2101
4.2:
Datasheet
STOP
P
1