SLASF44 may   2023 AFE78201 , AFE88201

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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  Timing Diagrams
    8. 6.8  Typical Characteristics: VOUT DAC
    9. 6.9  Typical Characteristics: ADC
    10. 6.10 Typical Characteristics: Reference
    11. 6.11 Typical Characteristics: Power Supply
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Digital-to-Analog Converter (DAC) Overview
        1. 7.3.1.1 DAC Resistor String
        2. 7.3.1.2 DAC Buffer Amplifier
        3. 7.3.1.3 DAC Transfer Function
        4. 7.3.1.4 DAC Gain and Offset Calibration
        5. 7.3.1.5 Programmable Slew Rate
        6. 7.3.1.6 DAC Register Structure and CLEAR State
      2. 7.3.2  Analog-to-Digital Converter (ADC) Overview
        1. 7.3.2.1 ADC Operation
        2. 7.3.2.2 ADC Custom Channel Sequencer
        3. 7.3.2.3 ADC Synchronization
        4. 7.3.2.4 ADC Offset Calibration
        5. 7.3.2.5 External Monitoring Inputs
        6. 7.3.2.6 Temperature Sensor
        7. 7.3.2.7 Self-Diagnostic Multiplexer
        8. 7.3.2.8 ADC Bypass
      3. 7.3.3  Programmable Out-of-Range Alarms
        1. 7.3.3.1 Alarm-Based Interrupts
        2. 7.3.3.2 Alarm Action Configuration Register
        3. 7.3.3.3 Alarm Voltage Generator
        4. 7.3.3.4 Temperature Sensor Alarm Function
        5. 7.3.3.5 Internal Reference Alarm Function
        6. 7.3.3.6 ADC Alarm Function
        7. 7.3.3.7 Fault Detection
      4. 7.3.4  IRQ
      5. 7.3.5  Internal Reference
      6. 7.3.6  Integrated Precision Oscillator
      7. 7.3.7  Precision Oscillator Diagnostics
      8. 7.3.8  One-Time Programmable (OTP) Memory
      9. 7.3.9  GPIO
      10. 7.3.10 Timer
      11. 7.3.11 Unique Chip Identifier (ID)
      12. 7.3.12 Scratch Pad Register
    4. 7.4 Device Functional Modes
      1. 7.4.1 Register Built-In Self-Test (RBIST)
      2. 7.4.2 DAC Power-Down Mode
      3. 7.4.3 Reset
    5. 7.5 Programming
      1. 7.5.1 Communication Setup
        1. 7.5.1.1 SPI Mode
        2. 7.5.1.2 UART Mode
      2. 7.5.2 GPIO Programming
      3. 7.5.3 Serial Peripheral Interface (SPI)
        1. 7.5.3.1 SPI Frame Definition
        2. 7.5.3.2 SPI Read and Write
        3. 7.5.3.3 Frame Error Checking
        4. 7.5.3.4 Synchronization
      4. 7.5.4 UART Interface
        1. 7.5.4.1 UART Break Mode (UBM)
      5. 7.5.5 Status Bits
      6. 7.5.6 Watchdog Timer
    6. 7.6 Register Maps
      1. 7.6.1 AFEx8201 Registers
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Multichannel Configuration
    2. 8.2 Typical Application
      1. 8.2.1 Analog Output Module
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 XTR305
            1. 8.2.1.2.1.1 Current-Output Mode
            2. 8.2.1.2.1.2 Voltage Output Mode
            3. 8.2.1.2.1.3 Diagnostic Features
        3. 8.2.1.3 Application Curves
    3. 8.3 Initialization Setup
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  10. 10Mechanical, Packaging, and Orderable Information

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7.5.3.4 Synchronization

The AFEx8201 register map runs on the internal clock domain. Both the SPI and UBM packets are synchronized to this domain. This synchronization adds a latency of 0.4 µs to 1.22 µs (1.5 internal clocks), with respect to the rising edge of CS or the STOP bit of the last byte of the UBM packet.

The effect of clock synchronization on UBM communication is not evident because of the lower speed and asynchronous nature of UBM communication.

In SPI mode, if changing register bits CONFIG.DSDO, CONFIG.FSDO, or CONFIG.CRC_EN, keep CS high for at least two clock cycles before issuing the next frame. Frame data corruption can occur if the two extra cycles are not used. The following are examples of frame corruption:

  • Setting CONFIG.DSDO = 0: SDO begins to drive in the middle of the next frame.
  • Changing CONFIG.FSDO: The launching edge of SDO changes in the middle of the next frame.
  • Setting CONFIG.CRC_EN = 1: The next frame has a CRC error because the CRC is enabled in the middle of the frame.

Send a NOP command (SDI = 0x00_0000) after setting the DSDO, FSDO, and CRC_EN bits to prevent the corrupted frames from impacting communication. Sending a NOP after CONFIG.CRC_EN is set still generates a CRC error, and is reported in the STATUS portion of SDO. To avoid false errors, wait approximately 2 µs after setting CONFIG.CRC_EN before sending the next frame.