High-Side Current-Sense and Internal 1°C Temperature Monitor
Datasheet
3.2
SMBus Protocols
The EMC1701 is SMBus 2.0 compatible and supports Send Byte, Read Byte, Receive Byte, Write
Byte, Block Read, and Block Write as valid protocols. It will respond to the Alert Response Address
protocol but is not in full compliance.
All of the protocols listed below use the convention in Table 3.2.
Table 3.2 Protocol Format
DATA SENT
TO DEVICE
DATA SENT TO
THE HOST
# of bits sent
# of bits sent
3.2.1
Write Byte
The Write Byte is used to write one byte of data to the registers, as shown in Table 3.3:
Table 3.3 Write Byte Protocol
SLAVE
ADDRESS
REGISTER
ADDRESS
REGISTER
DATA
START
1 -> 0
WR
ACK
ACK
ACK
STOP
YYYY_YYY
0
0
XXh
0
XXh
0
0 -> 1
3.2.2
Read Byte
The Read Byte protocol is used to read one byte of data from the registers, as shown in Table 3.4.
Table 3.4 Read Byte Protocol
START
SLAVE
ADDRESS
WR
ACK
Register
Address
ACK
START
Slave
Address
RD
ACK
Register
Data
NACK
STOP
1 -> 0
YYYY_YYY
0
0
XXh
0
0 -> 1
YYYY_YYY
1
0
XXh
1
0 -> 1
3.2.3
Send Byte
The Send Byte protocol is used to set the internal address register pointer to the correct address
location. No data is transferred during the Send Byte protocol, as shown in Table 3.5.
Table 3.5 Send Byte Protocol
SLAVE
ADDRESS
REGISTER
ADDRESS
START
WR
ACK
ACK
STOP
1 -> 0
YYYY_YYY
0
0
XXh
0
0 -> 1
SMSC EMC1701
Revision 1.2 (09-27-10)
DATA1S7HEET
SMSC [ SMSC CORPORATION ]
