SBAS979C June   2019  – September 2024 ADS7038

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Timing Diagrams
    9. 6.9 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Multiplexer and ADC
      2. 7.3.2  Reference
      3. 7.3.3  ADC Transfer Function
      4. 7.3.4  ADC Offset Calibration
      5. 7.3.5  Programmable Averaging Filter
      6. 7.3.6  General-Purpose I/Os
      7. 7.3.7  Oscillator and Timing Control
      8. 7.3.8  CRC on Data Interface
        1. 7.3.8.1 Input CRC (From Host To Device)
        2. 7.3.8.2 Output CRC (From Device to Host)
      9. 7.3.9  Output Data Format
        1. 7.3.9.1 Status Flags
      10. 7.3.10 Digital Window Comparator
        1. 7.3.10.1 Interrupts From Digital Inputs
        2. 7.3.10.2 Triggering Digital Outputs with Alert and ZCD
      11. 7.3.11 Minimum, Maximum, and Latest Data Registers
      12. 7.3.12 Device Programming
        1. 7.3.12.1 Enhanced-SPI Interface
        2. 7.3.12.2 Register Read/Write Operation
          1. 7.3.12.2.1 Register Write
          2. 7.3.12.2.2 Register Read
            1. 7.3.12.2.2.1 Register Read With CRC
    4. 7.4 Device Functional Modes
      1. 7.4.1 Device Power-Up and Reset
      2. 7.4.2 Manual Mode
      3. 7.4.3 On-the-Fly Mode
      4. 7.4.4 Auto-Sequence Mode
      5. 7.4.5 Autonomous Mode
      6. 7.4.6 Turbo Comparator Mode
  9. 8 Register Map
    1. 8.1 ADS7038 Registers
      1. 8.1.1   SYSTEM_STATUS Register (Address = 0x0) [reset = 0x81]
      2. 8.1.2   GENERAL_CFG Register (Address = 0x1) [reset = 0x0]
      3. 8.1.3   DATA_CFG Register (Address = 0x2) [reset = 0x0]
      4. 8.1.4   OSR_CFG Register (Address = 0x3) [reset = 0x0]
      5. 8.1.5   OPMODE_CFG Register (Address = 0x4) [reset = 0x0]
      6. 8.1.6   PIN_CFG Register (Address = 0x5) [reset = 0x0]
      7. 8.1.7   GPIO_CFG Register (Address = 0x7) [reset = 0x0]
      8. 8.1.8   GPO_DRIVE_CFG Register (Address = 0x9) [reset = 0x0]
      9. 8.1.9   GPO_VALUE Register (Address = 0xB) [reset = 0x0]
      10. 8.1.10  GPI_VALUE Register (Address = 0xD) [reset = 0x0]
      11. 8.1.11  SEQUENCE_CFG Register (Address = 0x10) [reset = 0x0]
      12. 8.1.12  CHANNEL_SEL Register (Address = 0x11) [reset = 0x0]
      13. 8.1.13  AUTO_SEQ_CH_SEL Register (Address = 0x12) [reset = 0x0]
      14. 8.1.14  ALERT_CH_SEL Register (Address = 0x14) [reset = 0x0]
      15. 8.1.15  ALERT_MAP Register (Address = 0x16) [reset = 0x0]
      16. 8.1.16  ALERT_PIN_CFG Register (Address = 0x17) [reset = 0x0]
      17. 8.1.17  EVENT_FLAG Register (Address = 0x18) [reset = 0x0]
      18. 8.1.18  EVENT_HIGH_FLAG Register (Address = 0x1A) [reset = 0x0]
      19. 8.1.19  EVENT_LOW_FLAG Register (Address = 0x1C) [reset = 0x0]
      20. 8.1.20  EVENT_RGN Register (Address = 0x1E) [reset = 0x0]
      21. 8.1.21  HYSTERESIS_CH0 Register (Address = 0x20) [reset = 0xF0]
      22. 8.1.22  HIGH_TH_CH0 Register (Address = 0x21) [reset = 0xFF]
      23. 8.1.23  EVENT_COUNT_CH0 Register (Address = 0x22) [reset = 0x0]
      24. 8.1.24  LOW_TH_CH0 Register (Address = 0x23) [reset = 0x0]
      25. 8.1.25  HYSTERESIS_CH1 Register (Address = 0x24) [reset = 0xF0]
      26. 8.1.26  HIGH_TH_CH1 Register (Address = 0x25) [reset = 0xFF]
      27. 8.1.27  EVENT_COUNT_CH1 Register (Address = 0x26) [reset = 0x0]
      28. 8.1.28  LOW_TH_CH1 Register (Address = 0x27) [reset = 0x0]
      29. 8.1.29  HYSTERESIS_CH2 Register (Address = 0x28) [reset = 0xF0]
      30. 8.1.30  HIGH_TH_CH2 Register (Address = 0x29) [reset = 0xFF]
      31. 8.1.31  EVENT_COUNT_CH2 Register (Address = 0x2A) [reset = 0x0]
      32. 8.1.32  LOW_TH_CH2 Register (Address = 0x2B) [reset = 0x0]
      33. 8.1.33  HYSTERESIS_CH3 Register (Address = 0x2C) [reset = 0xF0]
      34. 8.1.34  HIGH_TH_CH3 Register (Address = 0x2D) [reset = 0xFF]
      35. 8.1.35  EVENT_COUNT_CH3 Register (Address = 0x2E) [reset = 0x0]
      36. 8.1.36  LOW_TH_CH3 Register (Address = 0x2F) [reset = 0x0]
      37. 8.1.37  HYSTERESIS_CH4 Register (Address = 0x30) [reset = 0xF0]
      38. 8.1.38  HIGH_TH_CH4 Register (Address = 0x31) [reset = 0xFF]
      39. 8.1.39  EVENT_COUNT_CH4 Register (Address = 0x32) [reset = 0x0]
      40. 8.1.40  LOW_TH_CH4 Register (Address = 0x33) [reset = 0x0]
      41. 8.1.41  HYSTERESIS_CH5 Register (Address = 0x34) [reset = 0xF0]
      42. 8.1.42  HIGH_TH_CH5 Register (Address = 0x35) [reset = 0xFF]
      43. 8.1.43  EVENT_COUNT_CH5 Register (Address = 0x36) [reset = 0x0]
      44. 8.1.44  LOW_TH_CH5 Register (Address = 0x37) [reset = 0x0]
      45. 8.1.45  HYSTERESIS_CH6 Register (Address = 0x38) [reset = 0xF0]
      46. 8.1.46  HIGH_TH_CH6 Register (Address = 0x39) [reset = 0xFF]
      47. 8.1.47  EVENT_COUNT_CH6 Register (Address = 0x3A) [reset = 0x0]
      48. 8.1.48  LOW_TH_CH6 Register (Address = 0x3B) [reset = 0x0]
      49. 8.1.49  HYSTERESIS_CH7 Register (Address = 0x3C) [reset = 0xF0]
      50. 8.1.50  HIGH_TH_CH7 Register (Address = 0x3D) [reset = 0xFF]
      51. 8.1.51  EVENT_COUNT_CH7 Register (Address = 0x3E) [reset = 0x0]
      52. 8.1.52  LOW_TH_CH7 Register (Address = 0x3F) [reset = 0x0]
      53. 8.1.53  RESERVED Register (Address = 0x4E) [reset = 0x0]
      54. 8.1.54  MAX_CH0_LSB Register (Address = 0x60) [reset = 0x0]
      55. 8.1.55  MAX_CH0_MSB Register (Address = 0x61) [reset = 0x0]
      56. 8.1.56  MAX_CH1_LSB Register (Address = 0x62) [reset = 0x0]
      57. 8.1.57  MAX_CH1_MSB Register (Address = 0x63) [reset = 0x0]
      58. 8.1.58  MAX_CH2_LSB Register (Address = 0x64) [reset = 0x0]
      59. 8.1.59  MAX_CH2_MSB Register (Address = 0x65) [reset = 0x0]
      60. 8.1.60  MAX_CH3_LSB Register (Address = 0x66) [reset = 0x0]
      61. 8.1.61  MAX_CH3_MSB Register (Address = 0x67) [reset = 0x0]
      62. 8.1.62  MAX_CH4_LSB Register (Address = 0x68) [reset = 0x0]
      63. 8.1.63  MAX_CH4_MSB Register (Address = 0x69) [reset = 0x0]
      64. 8.1.64  MAX_CH5_LSB Register (Address = 0x6A) [reset = 0x0]
      65. 8.1.65  MAX_CH5_MSB Register (Address = 0x6B) [reset = 0x0]
      66. 8.1.66  MAX_CH6_LSB Register (Address = 0x6C) [reset = 0x0]
      67. 8.1.67  MAX_CH6_MSB Register (Address = 0x6D) [reset = 0x0]
      68. 8.1.68  MAX_CH7_LSB Register (Address = 0x6E) [reset = 0x0]
      69. 8.1.69  MAX_CH7_MSB Register (Address = 0x6F) [reset = 0x0]
      70. 8.1.70  MIN_CH0_LSB Register (Address = 0x80) [reset = 0xFF]
      71. 8.1.71  MIN_CH0_MSB Register (Address = 0x81) [reset = 0xFF]
      72. 8.1.72  MIN_CH1_LSB Register (Address = 0x82) [reset = 0xFF]
      73. 8.1.73  MIN_CH1_MSB Register (Address = 0x83) [reset = 0xFF]
      74. 8.1.74  MIN_CH2_LSB Register (Address = 0x84) [reset = 0xFF]
      75. 8.1.75  MIN_CH2_MSB Register (Address = 0x85) [reset = 0xFF]
      76. 8.1.76  MIN_CH3_LSB Register (Address = 0x86) [reset = 0xFF]
      77. 8.1.77  MIN_CH3_MSB Register (Address = 0x87) [reset = 0xFF]
      78. 8.1.78  MIN_CH4_LSB Register (Address = 0x88) [reset = 0xFF]
      79. 8.1.79  MIN_CH4_MSB Register (Address = 0x89) [reset = 0xFF]
      80. 8.1.80  MIN_CH5_LSB Register (Address = 0x8A) [reset = 0xFF]
      81. 8.1.81  MIN_CH5_MSB Register (Address = 0x8B) [reset = 0xFF]
      82. 8.1.82  MIN_CH6_LSB Register (Address = 0x8C) [reset = 0xFF]
      83. 8.1.83  MIN_CH6_MSB Register (Address = 0x8D) [reset = 0xFF]
      84. 8.1.84  MIN_CH7_LSB Register (Address = 0x8E) [reset = 0xFF]
      85. 8.1.85  MIN_CH7_MSB Register (Address = 0x8F) [reset = 0xFF]
      86. 8.1.86  RECENT_CH0_LSB Register (Address = 0xA0) [reset = 0x0]
      87. 8.1.87  RECENT_CH0_MSB Register (Address = 0xA1) [reset = 0x0]
      88. 8.1.88  RECENT_CH1_LSB Register (Address = 0xA2) [reset = 0x0]
      89. 8.1.89  RECENT_CH1_MSB Register (Address = 0xA3) [reset = 0x0]
      90. 8.1.90  RECENT_CH2_LSB Register (Address = 0xA4) [reset = 0x0]
      91. 8.1.91  RECENT_CH2_MSB Register (Address = 0xA5) [reset = 0x0]
      92. 8.1.92  RECENT_CH3_LSB Register (Address = 0xA6) [reset = 0x0]
      93. 8.1.93  RECENT_CH3_MSB Register (Address = 0xA7) [reset = 0x0]
      94. 8.1.94  RECENT_CH4_LSB Register (Address = 0xA8) [reset = 0x0]
      95. 8.1.95  RECENT_CH4_MSB Register (Address = 0xA9) [reset = 0x0]
      96. 8.1.96  RECENT_CH5_LSB Register (Address = 0xAA) [reset = 0x0]
      97. 8.1.97  RECENT_CH5_MSB Register (Address = 0xAB) [reset = 0x0]
      98. 8.1.98  RECENT_CH6_LSB Register (Address = 0xAC) [reset = 0x0]
      99. 8.1.99  RECENT_CH6_MSB Register (Address = 0xAD) [reset = 0x0]
      100. 8.1.100 RECENT_CH7_LSB Register (Address = 0xAE) [reset = 0x0]
      101. 8.1.101 RECENT_CH7_MSB Register (Address = 0xAF) [reset = 0x0]
      102. 8.1.102 GPO0_TRIG_EVENT_SEL Register (Address = 0xC3) [reset = 0x0]
      103. 8.1.103 GPO1_TRIG_EVENT_SEL Register (Address = 0xC5) [reset = 0x0]
      104. 8.1.104 GPO2_TRIG_EVENT_SEL Register (Address = 0xC7) [reset = 0x0]
      105. 8.1.105 GPO3_TRIG_EVENT_SEL Register (Address = 0xC9) [reset = 0x0]
      106. 8.1.106 GPO4_TRIG_EVENT_SEL Register (Address = 0xCB) [reset = 0x0]
      107. 8.1.107 GPO5_TRIG_EVENT_SEL Register (Address = 0xCD) [reset = 0x0]
      108. 8.1.108 GPO6_TRIG_EVENT_SEL Register (Address = 0xCF) [reset = 0x0]
      109. 8.1.109 GPO7_TRIG_EVENT_SEL Register (Address = 0xD1) [reset = 0x0]
      110. 8.1.110 GPO_TRIGGER_CFG Register (Address = 0xE9) [reset = 0x0]
      111. 8.1.111 GPO_VALUE_TRIG Register (Address = 0xEB) [reset = 0x0]
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Mixed-Channel Configuration
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Digital Input
          2. 9.2.1.2.2 Digital Open-Drain Output
        3. 9.2.1.3 Application Curve
      2. 9.2.2 Digital Push-Pull Output Configuration
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 AVDD and DVDD 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 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

7.3.8 CRC on Data Interface

The ADS7028 features a cyclic redundancy check (CRC) module for checking the integrity of the data bits exchanged over the SPI interface. The CRC module is bidirectional, which appends an 8-bit CRC to every byte read from the device and also evaluates the CRC of every incoming byte over the SPI interface. The CRC module uses the CRC-8-CCITT polynomial (x8 + x2 + x + 1) for CRC computation.

To enable the CRC module, set the CRC_EN bit in the GENERAL_CFG register. Table 7-4 shows the different ways that a CRC error that occurs when configuring the ADS7028 can be detected.

Table 7-4 Configuring Channels as Analog Inputs or GPIOs
CRC ERROR NOTIFICATION CONFIGURATION DESCRIPTION
ALERT ALERT_CRCIN = 1b ALERT (internal signal) is asserted if a CRC error is detected
Status flags APPEND_STATUS = 10b 4-bit status flags are appended to the ADC data. See the Output Data Format section for details.
Register read — Read the CRCERR_IN bit to check if a CRC error was detected.

When the ADS7028 detects a CRC error on the SPI interface, the erroneous data are ignored and the CRCERR_IN bit is set. Additional notifications can be enabled as described in Table 7-4. Further register writes are disabled until the CRCERR_IN bit is cleared by writing 1b to this bit. When using autonomous conversion mode, further conversions can be disabled on a CRC error on the SPI interface by setting CONV_ON_ERR = 1b.