Troubleshooting

Common issues and solutions for the TMC9660 driver.

Bootloader Initialization Fails

Symptom

bootloaderInit() returns BootloaderInitResult::Failure

Solutions

  1. Check Hardware Reset
    • Ensure RST pin is properly toggled
    • Verify FAULTN pin monitoring during reset
    • Wait at least 100ms after reset
  2. Verify Communication Interface
    • Check SPI/UART wiring
    • Verify CS pin (SPI) or TX/RX pins (UART)
    • Confirm clock speed ≤ 4 MHz (SPI)
  3. Check Bootloader Configuration 
    1
2

    // CRITICAL: Must set boot mode to Parameter
cfg.boot.boot_mode = tmc9660::bootcfg::BootMode::Parameter;
  4. Verify Power Supply
    • Ensure stable power to TMC9660
    • Check voltage levels (12V-48V for motor supply)

No Reply from Device

Symptom

Communication timeouts, no response to commands

Solutions

  1. SPI Issues
    • Verify MOSI/MISO not swapped
    • Check CS pin polarity (active LOW)
    • Confirm SPI mode (Mode 0 or 3)
    • Reduce clock speed
  2. UART Issues
    • Verify TX/RX pins not swapped
    • Check baud rate matches configuration
    • Ensure GPIO pins match bootloader config
    • Try autobaud mode
  3. Check Connections
    • Verify all connections are secure
    • Check for loose wires
    • Verify common ground

Motor Not Starting

Symptom

Motor configured but not rotating

Solutions

  1. Verify Bootloader Initialization 
    1
2
3

    // Must initialize bootloader first
cfg.boot.start_motor_control = true;
auto result = driver.bootloaderInit(&cfg);
  2. Check Motor Configuration 
    1
2
3
4
5
6

    // Verify motor type is set
driver.motorConfig.setType(tmc9660::tmcl::MotorType::BLDC_MOTOR, 7);
   
// Verify commutation mode
driver.motorConfig.setCommutationMode(
    tmc9660::tmcl::CommutationMode::FOC_HALL);
  3. Check Current Limits 
    1
2

    // Ensure current limits are set
driver.motorConfig.setMaxTorqueCurrent(2000);
  4. Verify Target Values 
    1
2

    // Set target velocity or torque
driver.focControl.setTargetVelocity(1000);

Communication Errors

Symptom

CRC errors, checksum failures, invalid replies

Solutions

  1. Check Timing
    • Add delays between commands
    • Respect SPI delayed reply timing
    • Wait for UART reply before next command
  2. Verify Protocol
    • Check CRC/checksum calculation
    • Verify frame format (8 bytes SPI, 9 bytes UART)
    • Confirm address encoding
  3. Reduce Noise
    • Use shorter cables
    • Add pull-up/pull-down resistors
    • Check for ground loops

Sensor Issues

Symptom

Hall sensors or encoder not working

Solutions

  1. Check Sensor Wiring
    • Verify Hall sensor connections
    • Check encoder A/B signals
    • Confirm sensor power supply
  2. Verify Sensor Configuration 
    1
2
3
4
5

    // For Hall sensors
driver.feedbackSense.configureHall();
   
// For encoder
driver.feedbackSense.configureABNEncoder(2048);
  3. Check Commutation Mode 
    1
2
3

    // Must match sensor type
driver.motorConfig.setCommutationMode(
    tmc9660::tmcl::CommutationMode::FOC_HALL); // or FOC_ENCODER

Protection Faults

Symptom

Overcurrent, undervoltage, or overtemperature faults

Solutions

  1. Check Current Limits 
    1
2

    // Reduce current limits if overcurrent
driver.motorConfig.setMaxTorqueCurrent(1500);
  2. Verify Power Supply
    • Check voltage levels
    • Ensure adequate current capacity
    • Check for voltage drops
  3. Check Temperature
    • Ensure adequate cooling
    • Monitor temperature via telemetry
    • Reduce load if overheating

Debugging Tips

  1. Enable Debug Logging
    • Remove TMC9660_DISABLE_DEBUG_LOGGING define
    • Check serial output for detailed logs
  2. Verify Communication 
    1
2
3
4
5

    // Test basic communication
auto version = driver.bootloaderGetVersion();
if (version.has_value()) {
    printf("Communication OK\n");
}
  3. Check Telemetry 
    1
2
3
4

    // Monitor device status
int16_t temp;
driver.telemetry.getTemperature(temp);
printf("Temperature: %d\n", temp);

Getting Help