TMC2209 Arduino Library

The TMC2209 can operate in two modes. The library defaults to Voltage Control Mode for safety to prevent motor overheating during initial setup.

Voltage Control Mode

• Activation: Use disableAutomaticCurrentScaling().
• Behavior: Operates in a feed-forward velocity-controlled mode. It does not react to changes in supply voltage or motor stalls. It provides a stable amplitude but does not regulate actual current.
• Adjustment: You must manually adjust setPwmOffset(), setPwmGradient(), and setRunCurrent() to reach proper current levels.

Current Control Mode

• Activation: Use enableAutomaticCurrentScaling().
• Behavior: The driver measures actual current through the coils and adjusts the PWM automatically to maintain target levels, even if velocity, supply voltage, or load changes. This requires an automatic tuning (calibration) routine.
• Adjustment: Setting setRunCurrent() or setHoldCurrent() is sufficient; the driver automatically adjusts the offset and gradient during tuning.

When using the TMC2209 without a separate stepper motor controller, you can use its simple velocity control mode. In this mode, the motor velocity is set using the moveAtVelocity(int32_t microsteps_per_period) method.

Important Considerations:

• No Acceleration Control: The motor may slip when attempting to jump to a new velocity.
• Crude Position Control: Position can only be estimated by commanding a velocity for a specific duration, which is prone to error due to system delays.
• Velocity Calculation: The actual velocity depends on the TMC2209 clock frequency ($f_{clk}$).

Formula: microsteps_per_second = microsteps_per_period * (fclk Hz / 2^24)

Default (Internal 12 MHz clock): microsteps_per_second = microsteps_per_period * 0.715 Hz

// Example of setting velocity in simple mode
// The actual speed depends on the clock frequency (fclk)
driver.moveAtVelocity(microsteps_per_period);

The TMC2209 is an ultra-silent motor driver IC for two-phase stepper motors. To operate a stepper motor effectively, you must understand the distinction between a Controller and a Driver:

• Stepper Motor Controller: Responsible for commanding motor kinetics, torque, or kinematics (position, speed, and acceleration).
• Stepper Motor Driver: Responsible for commanding the electrical current through the motor coils to meet the requirements of the controller.

The TMC2209 can be used in two primary ways:

1. As a standalone driver: It requires an external controller to manage complex motion. It communicates via a UART serial interface and a step and direction interface.
2. As a combined driver and controller: It can operate independently in a limited velocity control mode. This mode lacks direct position or acceleration control and is best suited for simple applications where small position errors are acceptable.

You can manage multiple TMC2209 drivers using different addressing and wiring strategies.

1. Unidirectional: Multiple chips with identical settings

Connect all chips to the same serial line. No addressing is required; they will all receive the same commands in parallel.

2. Unidirectional: Multiple chips with different settings (One UART)

Assign unique serial addresses using the hardware pins MS1 and MS2. You must specify the address during setup().

3. Bidirectional: Multiple chips with different settings (One UART)

When using bidirectional communication on a single UART line with multiple addresses, you must increase the reply delay to prevent non-addressed chips from detecting transmission errors during read access.

Required Method: setReplyDelay(uint8_t delay)

#include <TMC2209.h>

TMC2209 stepper_driver_0;
const TMC2209::SerialAddress SERIAL_ADDRESS_0 = TMC2209::SERIAL_ADDRESS_0;
TMC2209 stepper_driver_1;
const TMC2209::SerialAddress SERIAL_ADDRESS_1 = TMC2209::SERIAL_ADDRESS_1;
const uint8_t REPLY_DELAY = 4;
const long SERIAL_BAUD_RATE = 115200;

void setup()
{
  stepper_driver_0.setup(Serial1, SERIAL_BAUD_RATE, SERIAL_ADDRESS_0);
  stepper_driver_0.setReplyDelay(REPLY_DELAY);
  
  stepper_driver_1.setup(Serial1, SERIAL_BAUD_RATE, SERIAL_ADDRESS_1);
  stepper_driver_1.setReplyDelay(REPLY_DELAY);
}