SBOSA15B September   2022  – January 2025 TMP1827

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Description (cont.)
  6. 5 Device Comparison
  7. 6 Pin Configuration and Functions
  8. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics
    6. 7.6  1-Wire® Interface Timing
    7. 7.7  Security Engine Characteristics
    8. 7.8  EEPROM Characteristics
    9. 7.9  Timing Diagrams
    10. 7.10 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Power Up
      2. 8.3.2  Power Mode Switch
      3. 8.3.3  Bus Pullup Resistor
      4. 8.3.4  Temperature Results
      5. 8.3.5  Temperature Offset
      6. 8.3.6  Temperature Alert
      7. 8.3.7  Standard Device Address
        1. 8.3.7.1 Unique 64-Bit Device Address and ID
      8. 8.3.8  Flexible Device Address
        1. 8.3.8.1 Non-Volatile Short Address
        2. 8.3.8.2 IO Hardware Address
        3. 8.3.8.3 Resistor Address
        4. 8.3.8.4 Combined IO and Resistor Address
      9. 8.3.9  CRC Generation
      10. 8.3.10 Functional Register Map
      11. 8.3.11 User Memory Map
      12. 8.3.12 SHA-256-HMAC Authentication Block
      13. 8.3.13 Bit Communication
        1. 8.3.13.1 Host Write, Device Read
        2. 8.3.13.2 Host Read, Device Write
      14. 8.3.14 Bus Speed
      15. 8.3.15 NIST Traceability
    4. 8.4 Device Functional Modes
      1. 8.4.1 Conversion Modes
        1. 8.4.1.1 Basic One-Shot Conversion Mode
        2. 8.4.1.2 Auto Conversion Mode
        3. 8.4.1.3 Stacked Conversion Mode
        4. 8.4.1.4 Continuous Conversion Mode
      2. 8.4.2 Alert Function
        1. 8.4.2.1 Alert Mode
        2. 8.4.2.2 Comparator Mode
      3. 8.4.3 1-Wire® Interface Communication
        1. 8.4.3.1 Bus Reset Phase
        2. 8.4.3.2 Address Phase
          1. 8.4.3.2.1 READADDR (33h)
          2. 8.4.3.2.2 MATCHADDR (55h)
          3. 8.4.3.2.3 SEARCHADDR (F0h)
          4. 8.4.3.2.4 ALERTSEARCH (ECh)
          5. 8.4.3.2.5 SKIPADDR (CCh)
          6. 8.4.3.2.6 OVD SKIPADDR (3Ch)
          7. 8.4.3.2.7 OVD MATCHADDR (69h)
          8. 8.4.3.2.8 FLEXADDR (0Fh)
        3. 8.4.3.3 Function Phase
          1. 8.4.3.3.1  CONVERTTEMP (44h)
          2. 8.4.3.3.2  WRITE SCRATCHPAD-1 (4Eh)
          3. 8.4.3.3.3  READ SCRATCHPAD-1 (BEh)
          4. 8.4.3.3.4  COPY SCRATCHPAD-1 (48h)
          5. 8.4.3.3.5  WRITE SCRATCHPAD-2 (0Fh)
          6. 8.4.3.3.6  READ SCRATCHPAD-2 (AAh)
          7. 8.4.3.3.7  COPY SCRATCHPAD-2 (55h)
          8. 8.4.3.3.8  READ EEPROM (F0h)
          9. 8.4.3.3.9  GPIO WRITE (A5h)
          10. 8.4.3.3.10 GPIO READ (F5h)
      4. 8.4.4 NVM Operations
        1. 8.4.4.1 Programming User Data
        2. 8.4.4.2 Register and Memory Protection
          1. 8.4.4.2.1 Scratchpad-1 Register Protection
          2. 8.4.4.2.2 User Memory Protection
    5. 8.5 Programming
      1. 8.5.1 Single Device Temperature Conversion and Read
      2. 8.5.2 Multiple Device Temperature Conversion and Read
      3. 8.5.3 Register Scratchpad-1 Update and Commit
      4. 8.5.4 Single Device EEPROM Programming and Verify
      5. 8.5.5 Single Device EEPROM Page Lock Operation
      6. 8.5.6 Multiple Device IO Read
      7. 8.5.7 Multiple Device IO Write
    6. 8.6 Register Map
      1. 8.6.1  Temperature Result LSB Register (Scratchpad-1 offset = 00h) [reset = 00h]
      2. 8.6.2  Temperature Result MSB Register (Scratchpad-1 offset = 01h) [reset = 00h]
      3. 8.6.3  Status Register (Scratchpad-1 offset = 02h) [reset = 3Ch]
      4. 8.6.4  Device Configuration-1 Register (Scratchpad-1 offset = 04h) [reset = 70h]
      5. 8.6.5  Device Configuration-2 Register (Scratchpad-1 offset = 05h) [reset = 80h]
      6. 8.6.6  Short Address Register (Scratchpad-1 offset = 06h) [reset = 00h]
      7. 8.6.7  Temperature Alert Low LSB Register (Scratchpad-1 offset = 08h) [reset = 00h]
      8. 8.6.8  Temperature Alert Low MSB Register (Scratchpad-1 offset = 09h) [reset = 00h]
      9. 8.6.9  Temperature Alert High LSB Register (Scratchpad-1 offset = 0Ah) [reset = F0h]
      10. 8.6.10 Temperature Alert High MSB Register (Scratchpad-1 offset = 0Bh) [reset = 07h]
      11. 8.6.11 Temperature Offset LSB Register (Scratchpad-1 offset = 0Ch) [reset = 00h]
      12. 8.6.12 Temperature Offset MSB Register (Scratchpad-1 offset = 0Dh) [reset = 00h]
      13. 8.6.13 IO Read Register [reset = F0h]
      14. 8.6.14 IO Configuration Register [reset = 00h]
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Bus Powered Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
      2. 9.2.2 Supply Powered Application
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
      3. 9.2.3 UART Interface for Communication
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.9 CRC Generation

The TMP1827 implements a cyclic redundancy check (CRC) mechanism for data integrity check and communication robustness. Table 8-4 lists the properties of a 8-bit CRC.

Table 8-4 CRC-8 Rule
CRC-8 RULEATTRIBUTES
CRC width8 bits
CRC polynomialx8 + x5 + x4 + 1 (0x31)
Initial seed value00h
Input data reflectedYes
Output data reflectedYes
XOR value00h

When a new transaction is done, the shift register is initialized with the seed value of 00h and the data is shifted in LSB first. The CRC result is always part of the 64-bit unique address and is computed on the preceding 56-bits. Additionally, when the host writes to the scratchpad-1 for the registers and scratchpad-2 for the memory, the device sends the CRC computed on the data bytes to provide a data integrity check for the host on the transaction. When the host reads the scratchpad-1 for reading the temperature register, the device shall append the CRC after the 8 bytes of scratchpad are sent.

The host must recalculate the CRC and compares the recalculation against the received CRC from the device. This is done by shifting the read data from the device along with CRC bits. If there is no bus error, then the shift register at the end of the bit shift results in 00h. When writing the data to the device, the host must check the CRC received by processing the write data to verify that there are no transmission errors and take appropriate corrective action before performing the next function.