SNIS137G August   2004  – August 2019 LM95071

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Temperature Monitor Application
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Function
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Ratings
    4. 6.4 Thermal Information
    5. 6.5 Temperature-to-Digital Converter Characteristics
    6. 6.6 Logic Electrical Characteristics - Digital DC Characteristics
    7. 6.7 Logic Electrical Characteristics - Serial Bus Digital Switching Characteristics
    8. 6.8 Timing Diagrams
    9. 6.9 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Power Up and Power Down
      2. 8.3.2 Temperature Data Format
      3. 8.3.3 Tight Accuracy, Fine Resolution and Low Noise
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode/Manufacturer ID
    5. 8.5 Programming
      1. 8.5.1 Serial Bus Interface
      2. 8.5.2 Serial Bus Timing Diagrams
    6. 8.6 Register Maps
      1. 8.6.1 Internal Register Structure
        1. 8.6.1.1 Configuration Register
        2. 8.6.1.2 Temperature Register
        3. 8.6.1.3 Manufacturer/Device ID Register
  9. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Community Resource
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  10. 10Mechanical, Packaging, and Orderable Information

8.5.1 Serial Bus Interface

The LM95071 operates as a slave and is compatible with SPI or MICROWIRE bus specifications. Data is clocked out on the falling edge of the serial clock (SC), while data is clocked in on the rising edge of SC. A complete communication is framed by falling and rising chip select (CS) signal. The CS signal should be held high for at least one clock cycle (160 ns minimum) between communications. The transmit-only communication (register read) consists of 16 clock cycles. A complete transmit/receive communication will consist of 32 serial clocks (see Serial Bus Timing Diagrams). The first 16 clocks comprise the transmit phase of communication, while the second 16 clocks are the receive phase.

When CS is high SI/O will be in TRI-STATE. Communication should be initiated by taking chip select (CS) low. This should not be done when SC is changing from a low to high state. Once CS is low the serial I/O pin (SI/O) will transmit the first bit of data. The master can then read this bit with the rising edge of SC. The remainder of the data will be clocked out by the falling edge of SC. CS can be taken high at any time during the transmit phase. If CS is brought low in the middle of a conversion the LM95071 will complete the conversion and the output shift register will be updated after CS is brought back high.

The receive phase of a communication starts after 16 SC periods. CS can remain low for 32 SC cycles. The LM95071/LM95071-Q1 will read the data available on the SI/O line on the rising edge of the serial clock. Input data is to an 8-bit shift register. The part will detect the last eight bits shifted into the register. The receive phase can last up to 16 SC periods. All ones must be shifted in order to place the part into shutdown. All zeros must be shifted in order to place the LM95071 into continuous conversion mode. Only the following codes should be transmitted to the LM95071:

  • 00 hex for continuous conversion
  • FF hex for shutdown

Another code may place the part into a test mode. Test modes are used by Texas Instruments to thoroughly test the function of the LM95071 during production testing. Only eight bits have been defined above since only the last eight transmitted are detected by the LM95071, before CS is taken HIGH.

The following communication can be used to determine the Manufacturer's/Device ID and then immediately place the part into continuous conversion mode. With CS continuously low:

  • Read 16 bits of temperature data
  • Write 16 bits of data commanding shutdown
  • Read 16 bits of Manufacture's/Device ID data
  • Write 8 to 16 bits of data commanding Conversion Mode
  • Take CS HIGH.

Note that 228 ms (max) will have to pass for a conversion to complete before the LM95071 actually transmits temperature data.