EMC1053 Datasheet, PDF (6/24 Pages) SMSC Corporation – 1C Triple Temperature Sensor with Resistance Error Correction and Hotter of Two Zones

2.3
1°C Triple Temperature Sensor with Resistance Error Correction and Hotter of Two Zones
System Management Bus Interface Protocol
Datasheet
A host controller, such as an SMSC I/O controller, communicates with the EMC1053 via the two wire
serial interface named SMBus. The SMBus interface is used to read and write registers in the
EMC1053, which is a slave-only device. A detailed timing diagram is shown in Figure 2.1.
SMCLK
T_LOW
T_HIGH
T_R
T_F
T_HD:STA
T_SU:STO
T_HD:STA
T_HD:DAT T_SU:DAT
T_SU:STA
SMDATA
T_BUF
P
S
S - Start Condition
S
P - Stop Condition ^P
Figure 2.1 System Management Bus Timing Diagram
The EMC1053 implements a subset of the SMBus specification and supports Write Byte, Read Byte,
Send Byte, and Receive Byte protocols as shown. In the tables that describe the protocol, the “gray”
columns indicate that the slave is driving the bus.
All of the below protocols use the following convention:
2.3.1
DATA SENT
TO DEVICE
# of bits sent
DATA SENT TO
THE HOST
# of bits sent
Write Byte
The Write Byte is used to write one byte of data to the registers as shown in Table 2.3.
2.3.2
Table 2.3 Write Byte Protocol
START SLAVE ADDRESS WR ACK COMMAND ACK DATA ACK STOP
1
7
1
1
8
1
8
1
1
Read Byte
The Read Byte protocol is used to read one byte of data from the registers as shown in Table 2.4.
Table 2.4 Read Byte Protocol
START SLAVE ADDRESS WR ACK COMMAND ACK START SLAVE ADDRESS RD ACK DATA NACK STOP
1
7
1
1
8
1
1
7
1
1
8
1
1
2.3.3
Send Byte
The Send Byte protocol is used to set the Internal Address Register to the correct Address as shown
in Table 2.5. The Send Byte can be followed by the Receive Byte protocol described in Table 2.6 to
Revision 0.58 (09-26-05)
6
DATASHEET
SMSC EMC1053