41.2. Tamagawa Encoder Communication

41.2.1. Overview

This example demonstrates communication with Tamagawa encoders using multiple peripherals (PLA, DMA, SPI, QEI, PWM). Main features include:

  • Support for multiple DataID data acquisition: - ID0/ID7/ID8/IDC: Get absolute position data - ID1: Get multi-turn data - ID2: Get ID information - ID3: Get complete status (including position, multi-turn, ID and alarm information)

  • EEPROM operations: - Support EEPROM read/write - Automatic EEPROM busy status detection - Address range: 0-127

  • Complete error detection mechanism: - CRC verification - Communication error detection - Encoder error status monitoring - Command response verification

  • High-precision timing control: - Automatic communication delay compensation - PLA-based precise timing - DMA chained transfer

41.2.2. Board Setting

  • Core board

  • Expansion board: TMAGAWA RevA

  • Supported encoder model: TS5700N8401

  • Wiring requirements: - Plug TMAGAWA RevA into the core board - Correctly connect encoder to expansion board - Ensure J2’s P1 and P2 on expansion board are connected

41.2.3. Software Architecture

Main modules:

  1. Protocol Layer (tamagawa_proc): - Command formatting - CRC verification - Data parsing - Error handling

  2. Hardware Driver Layer: - PLA configuration: For precise timing and signal synchronization - DMA setup: Implement efficient data transfer - SPI configuration: Communication interface with encoder - QEI: Capture timing signals - PWM: Generate reference clock

  3. Application Layer: - Device initialization - Communication management - Data processing and display

41.2.4. Running the example

When the project is running correctly, the serial terminal will output the following information, and the position information will change when the encoder axis is rotated:

cmd:3 time:638, abs pos:4170741, abm pos:0, id:23.
cmd:3 time:631, abs pos:4170741, abm pos:0, id:23.
cmd:3 time:631, abs pos:4170740, abm pos:0, id:23.
cmd:3 time:634, abs pos:4170740, abm pos:0, id:23.
cmd:3 time:639, abs pos:4170741, abm pos:0, id:23.
cmd:3 time:632, abs pos:4170741, abm pos:0, id:23.
cmd:3 time:630, abs pos:4170742, abm pos:0, id:23.

Display information explanation: - cmd: Current command ID - time: Communication delay time (unit: system clock cycles) - abs pos: Absolute position value - abm pos: Multi-turn position value - id: Encoder ID

Note

  • Call tmgw_message_process function to update the data of tmgw_msg, which contains the information of the above function

  • Switching command, you need to modify tmgw_dev.comm_time_delay_config to turn off the communication function, and then do the configuration of PLA, DMA. Otherwise, it will generate an error message once and then return to normal