EMC1412-A-ACZL-TR SMSC, EMC1412-A-ACZL-TR Datasheet - Page 13

• Manufacturer Part Number: EMC1412-A-ACZL-TR
• Description: Board Mount Temperature Sensors SMBus Temp Sensor Selectable Address
• Manufacturer: SMSC

Specifications of EMC1412-A-ACZL-TR

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

Multiple Channel 1°C Temperature Sensor with Beta Compensation
Datasheet
Chapter 5 System Management Bus Interface Protocol
.
SMSC EMC1412
5.1
5.1.1
5.1.2
SMDATA
SMCLK
P
The EMC1412 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.
SMBus Start Bit
The SMBus Start bit is defined as a transition of the SMBus Data line from a logic ‘1’ state to a logic
‘0’ state while the SMBus Clock line is in a logic ‘1’ state.
SMBus Address and RD / WR Bit
The SMBus Address Byte consists of the 7-bit client address followed by the RD / WR indicator bit. If
this RD / WR bit is a logic ‘0’, the SMBus Host is writing data to the client device. If this RD / WR bit
is a logic ‘1’, the SMBus Host is reading data from the client device.
The EMC1412-A SMBus slave address is determined by the pull-up resistor on the THERM pin as
shown in
The Address decode is performed by pulling known currents from VDD through the external resistor
causing the pin voltage to drop based on the respective current / resistor relationship. This pin voltage
is compared against a threshold that determines the value of the pull-up resistor.
Communications Protocol
T
BUF
S
Table 5.1, "SMBus Address
T
HD:STA
T
LOW
T
PULL UP RESISTOR ON
HD:DAT
T
RISE
THERM PIN (±5%)
Figure 5.1 SMBus Timing Diagram
Table 5.1 SMBus Address Decode
S - Start Condition
T
HIGH
4.7k
6.8k
10k
15k
T
SU:DAT
DATASHEET
Decode".
T
FALL
13
Figure
SMBUS ADDRESS
1011_100(r/w)b
1001_100(r/w)b
1101_100(r/w)b
1111_100(r/w)b
5.1.
S
T
T
SU:STA
HD:STA
P - Stop Condition
Revision 1.38 (10-25-10)
T
SU:STO
P