TIDUF97 September   2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 TMAG6180-Q1
      2. 2.3.2 MSPM0G3507
      3. 2.3.3 THVD1454
  9. 3System Design Theory
    1. 3.1 Hardware Design
      1. 3.1.1 Angle Sensor Schematic Design
      2. 3.1.2 MSPM0G3507 Schematic Design
      3. 3.1.3 RS485 Transceiver Schematic Design
      4. 3.1.4 Power Supply and Reference Voltage
    2. 3.2 Software Design
      1. 3.2.1 Angle Calculation Timing
      2. 3.2.2 Rotary Angle Calculation
      3. 3.2.3 Rotary Angle Error Sources and Compensation
      4. 3.2.4 Encoder Communication Interface
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
      1. 4.1.1 PCB Overview
      2. 4.1.2 Encoder and JTAG Interface
      3. 4.1.3 Software Requirements
    2. 4.2 Test Setup
    3. 4.3 Test Results
      1. 4.3.1 AMR Sensor Sin and Cos Outputs Measurement
      2. 4.3.2 Static Angle Noise Measurement
      3. 4.3.3 Rotary Angle Accuracy Measurement
        1. 4.3.3.1 Impact of Airgap on Noise, Harmonics, and Total Angle Accuracy
      4. 4.3.4 RS485 Interface and Signal Integrity
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
      3. 5.1.3 PCB Layout
      4. 5.1.4 Altium Project Files
      5. 5.1.5 Gerber Files
      6. 5.1.6 Assembly Drawings
    2. 5.2 Tools and Software
    3. 5.3 Documentation Support
    4. 5.4 Support Resources
    5. 5.5 Trademarks
  12. 6About the Authors

4.3.4 RS485 Interface and Signal Integrity

TIDA-010947 Timing Diagram (Tamagawa T-format) to Request New Angle DataFigure 4-21 Timing Diagram (Tamagawa T-format) to Request New Angle Data

Figure 4-21 shows the communication timing diagram between host controller and TIDA-010947. The communication is based on T-format protocol. The host controller sends a command request every 62.5us (32kHz), TIDA-010947 responds with the corresponding angle data within 2us. The request command takes 6us and response data takes 35us.

In Figure 4-22 shows the rise and fall time of RS485 signal, which are around 40ns. Since UART baud rate is 4M, 1bit signal can last 250ns, so the rise and fall time do not influence communication.

TIDA-010947 RS485 Signal Rise and Fall TimeFigure 4-22 RS485 Signal Rise and Fall Time