TIDUA05B June   2015  – March 2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1 System Description
    1. 1.1 Design Overview
    2. 1.2 Analog Sin/Cos Incremental Encoder
      1. 1.2.1 Sin/Cos Encoder Output Signals
      2. 1.2.2 Sin/Cos Encoder Electrical Parameter Examples
    3. 1.3 Method to Calculate High-Resolution Position With Sin/Cos Encoders
      1. 1.3.1 Theoretical Approach
        1. 1.3.1.1 Overview
        2. 1.3.1.2 Coarse Resolution Angle Calculation
        3. 1.3.1.3 Fine Resolution Angle Calculation
        4. 1.3.1.4 Interpolated High-Resolution Angle Calculation
        5. 1.3.1.5 Practical Implementaion for Non-Ideal Synchronization
        6. 1.3.1.6 Resolution, Accuracy, and Speed Considerations
    4. 1.4 Sin/Cos Encoder Parameters Impact on Analog Circuit Specification
      1. 1.4.1 Analog Signal Chain Design Consideration for Phase Interpolation
      2. 1.4.2 Comparator Function System Design for Incremental Count
  8. 2 Design Features
    1. 2.1 Sin/Cos Encoder Interface
    2. 2.2 Host Processor Interface
    3. 2.3 Evaluation Firmware
    4. 2.4 Power Management
    5. 2.5 EMC Immunity
  9. 3 Block Diagram
  10. 4 Circuit Design and Component Selection
    1. 4.1 Analog Signal Chain
      1. 4.1.1 High-Resolution Signal Path With 16-Bit Dual Sampling ADC
        1. 4.1.1.1 Component Selection
        2. 4.1.1.2 Input Signal Termination and Protection
        3. 4.1.1.3 Differential Amplifier THS4531A and 16-Bit ADC ADS8354
      2. 4.1.2 Analog Signal Path With Single-Ended Output for MCU With Embedded ADC
      3. 4.1.3 Comparator Subsystem for Digital Signals A, B, and R
        1. 4.1.3.1 Non-Inverting Comparator With Hysteresis
    2. 4.2 Power Management
      1. 4.2.1 24-V Input to 6-V Intermediate Rail
      2. 4.2.2 Encoder Supply
      3. 4.2.3 Signal Chain Power Supply 5 V and 3.3 V
    3. 4.3 Host Processor Interface
      1. 4.3.1 Signal Description
      2. 4.3.2 High-Resolution Path Using 16-Bit Dual ADC ADS8354 With Serial Output
        1. 4.3.2.1 ADS8354 Input Full Scale Range Output Data Format
        2. 4.3.2.2 ADS8354 Serial Interface
        3. 4.3.2.3 ADS8354 Conversion Data Read
        4. 4.3.2.4 ADS8354 Register Configuration
    4. 4.4 Encoder Connector
    5. 4.5 Design Upgrades
  11. 5 Software Design
    1. 5.1 Overview
    2. 5.2 C2000 Piccolo Firmware
    3. 5.3 User Interface
  12. 6 Getting Started
    1. 6.1 TIDA-00176 PCB Overview
    2. 6.2 Connectors and Jumper Settings
      1. 6.2.1 Connector and Jumpers Overview
      2. 6.2.2 Default Jumper Configuration
    3. 6.3 Design Evaluation
      1. 6.3.1 Prerequisites
      2. 6.3.2 Hardware Setup
      3. 6.3.3 Software Setup
      4. 6.3.4 User Interface
  13. 7 Test Results
    1. 7.1 Analog Performance Tests
      1. 7.1.1 High-Resolution Signal Path
        1. 7.1.1.1 Bode Plot of Analog Path from Encoder Connector to ADS8354 Input
        2. 7.1.1.2 Performance Plots (DFT) for Entire High-Resulation Signal Path
        3. 7.1.1.3 Background on AC Performance Definitions With ADCs
      2. 7.1.2 Differential to Single-Ended Analog Signal Path
      3. 7.1.3 Comparator Subsystem With Digital Output Signals ATTL, BTTL, and RTTL
    2. 7.2 Power Supply Tests
      1. 7.2.1 24-V DC/DC Input Supply
        1. 7.2.1.1 Load-Line Regulation
        2. 7.2.1.2 Output Voltage Ripple
        3. 7.2.1.3 Switching Node and Switching Frequency
        4. 7.2.1.4 Efficiency
        5. 7.2.1.5 Bode Plot
        6. 7.2.1.6 Thermal Plot
      2. 7.2.2 Encoder Power Supply Output Voltage
      3. 7.2.3 5-V and 3.3-V Point-of-Load
    3. 7.3 System Performance
      1. 7.3.1 Sin/Cos Encoder Output Signal Emulation
        1. 7.3.1.1 One Period (Incremental Phase) Test
        2. 7.3.1.2 One Mechanical Revolution Test at Maximum Speed
    4. 7.4 Sin/Cos Encoder System Tests
      1. 7.4.1 Zero Index Marker R
      2. 7.4.2 Functional System Tests
    5. 7.5 EMC Test Result
      1. 7.5.1 Test Setup
      2. 7.5.2 IEC-61000-4-2 ESD Test Results
      3. 7.5.3 IEC-61000-4-4 EFT Test Results
      4. 7.5.4 IEC-61000-4-5 Surge Test Results
  14. 8 Design Files
    1. 8.1 Schematics
    2. 8.2 Bill of Materials
    3. 8.3 PCB Layout Guidelines
      1. 8.3.1 PCB Layer Plots
    4. 8.4 Altium Project
    5. 8.5 Gerber Files
    6. 8.6 Software Files
  15. 9 References
  16. 10About the Author
    1.     Recognition
  17. 11Revision History

6.3.2 Hardware Setup

The following connections are required between the TIDA-00176 and the InstaSPIN-MOTION LaunchPad.

Table 6-7 TIDA-00176 Host Processor Interface (J6) to InstaSPIN-LaunchPad
TIDA-00176 HOST PROCESSOR INTERFACE (J6)CONNECTS TO
→		InstaSPIN-MOTION LAUNCHPAD
J6-PINDESCRIPTIONHEADER-PINDESCRIPTION (3.3-V I/O)
1GNDJ3-Pin 22GND
19GNDJ2-Pin 20GND
2SDI (ADS8354)J2-Pin 15GPIO16/SPISIMOA
4/CS (ADS8354)J2-Pin 19
J6-Pin 59		GPIO27/eQEP2S and
GPIO19/SPISTEA
6SCLK (ADS8354)J1-Pin 7GPIO18/SPICLKA
8SDO_A (ADS8354)J2-Pin 14GPIO17/SPISOMIA
10SDO_B (ADS8354)NCNCNC
12A (TTL)J6-Pin 55GPIO24/eQEP2A
14B (TTL)J6-Pin 54GPIO25/eQEP2B
16R (TTL)J6-Pin 58GPIO26/eQEP2I
18A (single ended analog 0 to 3.3 V)J3-Pin 27ADCIN_A0
20B (single ended analog 0 to 3.3 V)J3-Pin 28ADCIN_B0

Follow these steps to setup the hardware:

  1. Connect the TIDA-00176 board with the InstaSPIN-MOTION LaunchPad using the proper connector or adapter.
    Note:

    For the internal testing an adapter board has been designed to interface between the
    TIDA-00176 and the InstaSPIN-MOTION LaunchPad as shown in Figure 6-2.

  2. Verify the TIDA-00176 is configured with the default three jumper settings per Section 6.2.2.
  3. Connect a Sin/Cos encoder to the board, by using either the SubD-15 connector (J8) or the SIL-8 connector (J9).
  4. Insert the 24-V input from the power brick in the J1 connector or use J2 connector in case of an external power supply (17 to 36 V) is preferred.
  5. Connect the USB mini cable from the InstaSPIN-MOTION LaunchPad to the PC.
    TIDA-00176 TIDA-00176 Board Mounted on InstaSPIN-MOTION LaunchPadFigure 6-2 TIDA-00176 Board Mounted on InstaSPIN-MOTION LaunchPad

Also refer to the InstaSPIN-MOTION LaunchPad prerequisites at: http://www.ti.com/tool/launchxl-f28069m

Ensure the following jumpers on the F28069 LaunchPad are set: JP1, JP2, JP3 and JP7. Do not set JP4, JP5 and JP6; these have to be not connected.