SPRACM3E August   2021  – January 2023 TMS320F280021 , TMS320F280021-Q1 , TMS320F280023 , TMS320F280023-Q1 , TMS320F280023C , TMS320F280025 , TMS320F280025-Q1 , TMS320F280025C , TMS320F280025C-Q1 , TMS320F280033 , TMS320F280034 , TMS320F280034-Q1 , TMS320F280036-Q1 , TMS320F280036C-Q1 , TMS320F280037 , TMS320F280037-Q1 , TMS320F280037C , TMS320F280037C-Q1 , TMS320F280038-Q1 , TMS320F280038C-Q1 , TMS320F280039 , TMS320F280039-Q1 , TMS320F280039C , TMS320F280039C-Q1 , TMS320F280040-Q1 , TMS320F280040C-Q1 , TMS320F280041 , TMS320F280041-Q1 , TMS320F280041C , TMS320F280041C-Q1 , TMS320F280045 , TMS320F280048-Q1 , TMS320F280048C-Q1 , TMS320F280049 , TMS320F280049-Q1 , TMS320F280049C , TMS320F280049C-Q1 , TMS320F28384D , TMS320F28384S , TMS320F28386D , TMS320F28386S , TMS320F28388D , TMS320F28388S , TMS320F28P650DH , TMS320F28P650DK , TMS320F28P650SH , TMS320F28P650SK , TMS320F28P659DH-Q1 , TMS320F28P659DK-Q1 , TMS320F28P659SH-Q1

 

  1.   Using the Fast Serial Interface (FSI) With Multiple Devices in an Application
  2.   Trademarks
  3. 1Introduction to the FSI Module
  4. 2FSI Applications
  5. 3Handshake Mechanism
    1. 3.1 Daisy-Chain Handshake Mechanism
    2. 3.2 Star Handshake Mechanism
  6. 4Sending and Receiving FSI Data Frames
    1. 4.1 FSI Data Frame Configuration APIs
    2. 4.2 Start Transmitting Data Frames
  7. 5Daisy-Chain Topology Tests
    1. 5.1 Two Device FSI Communication
      1. 5.1.1 CPU Control
      2. 5.1.2 DMA Control
      3. 5.1.3 Hardware Control
    2. 5.2 Three Device FSI Communication
      1. 5.2.1 CPU/DMA Control
      2. 5.2.2 Hardware Control
        1. 5.2.2.1 Skew Compensation for Three Device Daisy-Chain System
          1. 5.2.2.1.1 CPU/DMA control
          2. 5.2.2.1.2 Hardware Control
  8. 6Star Topology Tests
  9. 7Event Synchronization Over FSI
    1. 7.1 Introduction
      1. 7.1.1 Requirement of Event Sync for Distributed Systems
      2. 7.1.2 Solution Using FSI Event Sync Mechanism
      3. 7.1.3 Functional Overview of FSI Event Sync Mechanism
    2. 7.2 C2000Ware FSI EPWM Sync Examples
      1. 7.2.1 Location of the C2000Ware Example Project
      2. 7.2.2 Summary of Software Configurations
        1. 7.2.2.1 Lead Device Configuration
        2. 7.2.2.2 Node Device Configuration
      3. 7.2.3 1 Lead and 2 Node F28002x Device Daisy-Chain Tests
        1. 7.2.3.1 Hardware Setup and Configurations
        2. 7.2.3.2 Experimental Results
      4. 7.2.4 1 Lead and 8 Node F28002x Device Daisy-Chain Tests
        1. 7.2.4.1 Hardware Setup and Configurations
        2. 7.2.4.2 Experimental Results
      5. 7.2.5 Theoretical C2000 Uncertainties
    3. 7.3 Additional Tips and Usage of FSI Event Sync
      1. 7.3.1 Running the Example
      2. 7.3.2 Target Configuration File
      3. 7.3.3 Usage of Event Sync for Star Configuration
  10. 8References
  11. 9Revision History

7.3.3 Usage of Event Sync for Star Configuration

The star configuration is expected to be much simpler and provide better performance over the daisy-chain case since the delay from device-to-device transmission won’t be present. The factors which will affect the synchronism of EPWM signals for multiple devices will be the manufacturing uncertainty of the oscillator clock, distance between the devices and the isolators separating the devices. Daisy-chain example, in addition to the factors in Star connection, contains additive delay from device-to-device communication and the device uncertainties will add up for the last device in the chain, invoking higher complexity.

The user will need to make some minor changes in the existing code to ensure EPWM synchronization for the star configuration. All links between the lead and node devices will be direct connections. For the C2000Ware example code, the star configuration will have all the CLB counter ‘match’ values in the similar range dependent on the distances between lead and node devices and uncertainties in the communication path. The ‘match’ values will not add up from device to device as seen in the daisy-chain configuration. Therefore, the star event sync will offer lower event jitter. The lead device will have to be chosen such that it contains the number of FSIRX modules equal to or higher than the number of nodes so that one lead device is capable to connect with multiple node devices. For detailed information on the star configuration, see Section 6.