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DOC # 40DS5960.05

SM5221, SM5321 & SM5421 Series

www.si-micro.com

1. SCL Clock frequency:

•

100kHz to 400kHz

2. Slave Address

•

part will only respond to the set address.

3. Read Operations

•

the 7-bit slave address with the 8th bit = 1 (READ). The

sensor as the slave sends an acknowledge (ACK) indicating

success.

•

Read_DF3, and Read_DF4. The following figures show the

structure of the measurement packet for three of the four

•

For the Data Fetch commands, the number of data bytes

returned by the sensor is determined by when the master

sends the NACK and stop condition.

•

For the Read_DF3 data fetch command (Data Fetch 3

Bytes), the sensor returns three bytes in response to the

master sending the slave address and the READ bit (1): two

bytes of bridge data with the two status bits as the MSBs

and then 1 byte of temperature data (8-bit accuracy). After

receiving the required number of data bytes, the master

sends the NACK and stop condition to terminate the read

operation.

•

For the Read_DF4 command, the master delays sending the

NACK and continues reading an additional final byte to

acquire the full corrected 11-bit temperature measurement.

In this case, the last 5 bits of the final byte of the packet are

undetermined and should be masked off in the application.

•

The Read_DF2 command is used if corrected temperature is

not required. The master terminates the READ operation

after the two bytes of bridge data.

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