TIDUE74F April   2018  – March 2026

 

  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 Highlighted Products
      1. 2.2.1 C2000™ Real-Time MCU LaunchPad™ Development Kit
      2. 2.2.2 SN65HVD78
      3. 2.2.3 TLV702
      4. 2.2.4 TPS22918-Q1
    3. 2.3 Design Considerations
      1. 2.3.1 Tamagawa T-Format Protocol
      2. 2.3.2 C2000 T-Format Encoder Interface Overview
      3. 2.3.3 TIDM-1011 Board Implementation
      4. 2.3.4 MCU Resource Requirements
      5. 2.3.5 Device-Specific Resource Usage
        1. 2.3.5.1 CRC Calculations
        2. 2.3.5.2 Input, Output Signals, and CLB Tiles
      6. 2.3.6 CLB T-Format Implementation Details
        1. 2.3.6.1 Transaction Waveforms
          1. 2.3.6.1.1 IDLE State
          2. 2.3.6.1.2 TRANSMIT_DATA State
          3. 2.3.6.1.3 WAIT_FOR_START State
          4. 2.3.6.1.4 RECEIVE_DATA State
        2. 2.3.6.2 Communication Tile Design
        3. 2.3.6.3 Logic View
      7. 2.3.7 CLB Receive Data CRC Implementation
      8. 2.3.8 PM T-Format Encoder Interface Library
        1. 2.3.8.1 PM T-Format Reference Implementation Commands
        2. 2.3.8.2 Functions Supported in PM T-Format Reference Implementation
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware
      1. 3.1.1 TIDM-1011 Jumper Configuration
    2. 3.2 Software
      1. 3.2.1 C2000 Driver Library (DriverLib)
      2. 3.2.2 C2000 SysConfig
      3. 3.2.3 C2000 Configurable Logic Block Tool
      4. 3.2.4 Installing Code Composer Studio™ and C2000WARE-MOTORCONTROL-SDK
      5. 3.2.5 Locating the Reference Software
    3. 3.3 Testing and Results
      1. 3.3.1 Hardware Configuration
      2. 3.3.2 Building and Loading Project
      3. 3.3.3 Running Code
      4. 3.3.4 Cable Length Validation
      5. 3.3.5 Benchmarks
      6. 3.3.6 Troubleshooting
  10. 4Design Files
  11. 5Related Documentation
    1. 5.1 Trademarks
  12. 6Terminology
  13. 7About the Authors
  14. 8Revision History
2.3.6.1.2 TRANSMIT_DATA State

During the TRANSMIT_DATA (or SEND_DATA) state, the encoder interface sends the request to the encoder. The request is sent from the SPI TX FIFO on the falling edge of the SPICLK. During TRANSMIT_DATA, the CLB:

  • Enables transmission through the RS-485 driver by pulling the TxEN signal high.
  • Starts generation of the CLOCK signal. CLOCK becomes the CLB_SPI_CLOCK.
  • CLB_SPI_CLOCK drives the SPI module clock.
  • The CLOCK_COUNT (COUNTER_1) keeps track of the number of CLB_SPI_CLOCKs generated.

The number of CLB_SPI_CLOCKs required to send the transmission was loaded into both the match1 and match2 of the CLOCK_COUNT by the C28x during command setup.

Refer to: Figure 2-2, marker (2).

When the required number of clocks has been reached, the CLOCK_COUNT_COMPLETE (match2) and TRANSMIT_COMPLETE (match1) signals are pulled high. The effect is:

  • The main state machine transitions to WAIT_FOR_START
  • The CLOCK signal is disconnected from CLB_SPI_CLOCK
  • TxEN is driven low to give control of the RS-485 to the sensor or encoder.