SBAS590E March   2016  – June 2020 ADS131A02 , ADS131A04

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Simplified Block Diagram
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 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  Timing Requirements: Asynchronous Interrupt Interface Mode
    7. 7.7  Switching Characteristics: Asynchronous Interrupt Interface Mode
    8. 7.8  Timing Requirements: Synchronous Master Interface Mode
    9. 7.9  Switching Characteristics: Synchronous Master Interface Mode
    10. 7.10 Timing Requirements: Synchronous Slave Interface Mode
    11. 7.11 Switching Characteristics: Synchronous Slave Interface Mode
    12. 7.12 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Noise Measurements
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Clock
        1. 9.3.1.1 XTAL1/CLKIN and XTAL2
        2. 9.3.1.2 ICLK
        3. 9.3.1.3 MODCLK
        4. 9.3.1.4 Data Rate
      2. 9.3.2 Analog Input
      3. 9.3.3 Input Overrange and Underrange Detection
      4. 9.3.4 Reference
      5. 9.3.5 ΔΣ Modulator
      6. 9.3.6 Digital Decimation Filter
      7. 9.3.7 Watchdog Timer
    4. 9.4 Device Functional Modes
      1. 9.4.1 Low-Power and High-Resolution Mode
      2. 9.4.2 Power-Up
      3. 9.4.3 Standby and Wake-Up Mode
      4. 9.4.4 Conversion Mode
      5. 9.4.5 Reset (RESET)
    5. 9.5 Programming
      1. 9.5.1 Interface Protocol
        1. 9.5.1.1 Device Word Length
        2. 9.5.1.2 Fixed versus Dynamic-Frame Mode
        3. 9.5.1.3 Command Word
        4. 9.5.1.4 Status Word
        5. 9.5.1.5 Data Words
          1. 9.5.1.5.1 ADC Data Word 16-Bit Format
          2. 9.5.1.5.2 ADC Data Word 24-Bit Format
        6. 9.5.1.6 Hamming Code Error Correction
        7. 9.5.1.7 Cyclic Redundancy Check (CRC)
          1. 9.5.1.7.1 Computing the CRC
          2. 9.5.1.7.2 CRC With CRC_MODE = 1
          3. 9.5.1.7.3 CRC with CRC_MODE = 0
          4. 9.5.1.7.4 CRC Using the WREGS Command
      2. 9.5.2 SPI Interface
        1. 9.5.2.1 Asynchronous Interrupt Mode
          1. 9.5.2.1.1 Chip Select (CS)
          2. 9.5.2.1.2 Serial Clock (SCLK)
          3. 9.5.2.1.3 Data Input (DIN)
          4. 9.5.2.1.4 Data Output (DOUT)
          5. 9.5.2.1.5 Data Ready (DRDY)
          6. 9.5.2.1.6 Asynchronous Interrupt Mode Data Retrieval
        2. 9.5.2.2 Synchronous Master Mode
          1. 9.5.2.2.1 Serial Clock (SCLK)
          2. 9.5.2.2.2 Data Input (DIN)
          3. 9.5.2.2.3 Data Output (DOUT)
          4. 9.5.2.2.4 Data Ready (DRDY)
          5. 9.5.2.2.5 Chip Select (CS)
          6. 9.5.2.2.6 Synchronous Master Mode Data Retrieval
        3. 9.5.2.3 Synchronous Slave Mode
          1. 9.5.2.3.1 Chip Select (CS)
          2. 9.5.2.3.2 Serial Clock (SCLK)
          3. 9.5.2.3.3 Data Input (DIN)
          4. 9.5.2.3.4 Data Output (DOUT)
          5. 9.5.2.3.5 Data Ready (DRDY)
          6. 9.5.2.3.6 Synchronous Slave Mode Data Retrieval
        4. 9.5.2.4 ADC Frame Complete (DONE)
      3. 9.5.3 SPI Command Definitions
        1. 9.5.3.1  NULL: Null Command
        2. 9.5.3.2  RESET: Reset to POR Values
        3. 9.5.3.3  STANDBY: Enter Standby Mode
        4. 9.5.3.4  WAKEUP: Exit Standby Mode
        5. 9.5.3.5  LOCK: Lock ADC Registers
        6. 9.5.3.6  UNLOCK: Unlock ADC Registers
          1. 9.5.3.6.1 UNLOCK from POR or RESET
        7. 9.5.3.7  RREG: Read a Single Register
        8. 9.5.3.8  RREGS: Read Multiple Registers
        9. 9.5.3.9  WREG: Write Single Register
        10. 9.5.3.10 WREGS: Write Multiple Registers
    6. 9.6 Register Maps
      1. 9.6.1 User Register Description
        1. 9.6.1.1  ID_MSB: ID Control Register MSB (address = 00h) [reset = xxh]
          1. Table 16. ID_MSB Register Field Descriptions
        2. 9.6.1.2  ID_LSB: ID Control Register LSB (address = 01h) [reset = xxh]
          1. Table 17. ID_LSB Register Field Descriptions
        3. 9.6.1.3  STAT_1: Status 1 Register (address = 02h) [reset = 00h]
          1. Table 18. STAT_1 Register Field Descriptions
        4. 9.6.1.4  STAT_P: Positive Input Fault Detect Status Register (address = 03h) [reset = 00h]
          1. Table 19. STAT_P Register Field Descriptions
        5. 9.6.1.5  STAT_N: Negative Input Fault Detect Status Register (address = 04h) [reset = 00h]
          1. Table 20. STAT_N Register Field Descriptions
        6. 9.6.1.6  STAT_S: SPI Status Register (address = 05h) [reset = 00h]
          1. Table 21. STAT_S Register Field Descriptions
        7. 9.6.1.7  ERROR_CNT: Error Count Register (address = 06h) [reset = 00h]
          1. Table 22. ERROR_CNT Register Field Descriptions
        8. 9.6.1.8  STAT_M2: Hardware Mode Pin Status Register (address = 07h) [reset = xxh]
          1. Table 23. STAT_M2 Register Field Descriptions
        9. 9.6.1.9  Reserved Registers (address = 08h to 0Ah) [reset = 00h]
          1. Table 24. Reserved Registers Field Descriptions
        10. 9.6.1.10 A_SYS_CFG: Analog System Configuration Register (address = 0Bh) [reset = 60h]
          1. Table 25. A_SYS_CFG Register Field Descriptions
        11. 9.6.1.11 D_SYS_CFG: Digital System Configuration Register (address = 0Ch) [reset = 3Ch]
          1. Table 27. D_SYS_CFG Register Field Descriptions
        12. 9.6.1.12 CLK1: Clock Configuration 1 Register (address = 0Dh) [reset = 08h]
          1. Table 28. CLK1 Register Field Descriptions
        13. 9.6.1.13 CLK2: Clock Configuration 2 Register (address = 0Eh) [reset = 86h]
          1. Table 29. CLK2 Register Field Descriptions
        14. 9.6.1.14 ADC_ENA: ADC Channel Enable Register (address = 0Fh) [reset = 00h]
          1. Table 31. ADC_ENA Register Field Descriptions
        15. 9.6.1.15 Reserved Register (address = 10h) [reset = 00h]
          1. Table 32. Reserved Register Field Descriptions
      2. 9.6.2 ADCx: ADC Channel Digital Gain Configuration Registers (address = 11h to 14h) [reset = 00h]
        1. Table 33. ADCx Registers Field Descriptions
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Unused Inputs and Outputs
      2. 10.1.2 Power Monitoring Specific Applications
      3. 10.1.3 Multiple Device Configuration
        1. 10.1.3.1 First Device Configured in Asynchronous Interrupt Mode
        2. 10.1.3.2 First Device Configured in Synchronous Master Mode
        3. 10.1.3.3 All Devices Configured in Synchronous Slave Mode
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curve
    3. 10.3 What To Do and What Not To Do
    4. 10.4 Initialization Set Up
  11. 11Power Supply Recommendations
    1. 11.1 Negative Charge Pump
    2. 11.2 Internal Digital LDO
    3. 11.3 Power-Supply Sequencing
    4. 11.4 Power-Supply Decoupling
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Related Links
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Support Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

パッケージ・オプション

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メカニカル・データ（パッケージ｜ピン）
  • PBS|32
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発注情報

9.5.1.7.1 Computing the CRC

The CRC byte is the 16-bit remainder of the bitwise exclusive-OR (XOR) operation of the data bytes by a CRC polynomial. The CRC is based on the CRC-CCITT polynomial X16 + X12 + X5 + 1.

The binary coefficients of the polynomial are: 1 0001 0000 0010 0001. Calculate the CRC by dividing the data bytes (with the XOR operation, thus excluding the CRC) with the polynomial and compare the calculated CRC values to the provided CRC value. If the values do not match, then a data transmission error has occurred. In the event of a data transmission error, read or write the data again.

The following shows a general procedure to compute the CRC value. Assume the shift register is 16 bits wide:

  1. Set the polynomial value to 1021h
  2. Set the shift register to FFFFh
  3. For each byte in the data stream:
    • Shift the next data byte left by eight bits and XOR the result with the shift register, placing the result into the shift register
    • Do the following eight times:
      1. If the most significant bit of the shift register is set, shift the register left by one bit and XOR the result with the polynomial, placing the result into the shift register
      2. If the most significant bit of the shift register is not set, shift the register left by one bit
  4. The result in the shift register is the CRC check value

NOTE

The CRC algorithm used here employs an assumed set X16 bit. This bit is divided out by left-shifting the X16 bit 16 times out of the register prior to XORing with the polynomial register. This process makes the CRC calculable with a 16-bit word size.

The Communication Methods for Data Integrity Using Delta-Sigma Data Converters application report provides more information about CRC implementation, including example code.