Data Sheet

selected will start flowing through the coils, and the message at the bottom of the screen should

change to “Driving”.

If your power supply cannot supply enough current, its voltage might dip when you click the “Resume”

button. The Tic will detect that VIN has dropped too low (7.0 V for the Tic T825, 2.1 V for the Tic T834),

report a “Low VIN” error, and de-energize the motor. If this is happening in your system, what you

will see is that the Tic drives the motor briefly and then switches back to the previous state, where

the motor is de-energized because of a safe start violation. You can also look in the “Status” tab to

see if the “Low VIN” error has occurred: the count next to that error would be non-zero, and increase

every time you click “Resume”. If your power supply voltage is around 2.1 V to 2.3 V or drops to

that level when the motor is energized, the Tic T834 might report a “Motor driver error” (caused by

the DRV8834’s under-voltage lockout fault) without reporting a “Low VIN” error. An inadequate power

supply can also cause other problems, such as disrupting the USB communication or making the

Tic reset. If your system is having problems like this, you should try getting a better power supply or

lowering the current limit to address these issues before continuing.

Next, go to the “Status” tab and use the “Set target” interface at the bottom of that tab to command

your motor to go to different target positions. If the “Set target when slider or entry box are changed”

checkbox is checked, you can move the stepper motor by just dragging the scrollbar around. You

should make sure that your stepper motor can turn in both directions. If the stepper motor is not

moving correctly, you should turn off your motor power, check all of your connections (and soldering

joints, if applicable), and try again.

Checking the heat

After you have gotten your motor to move, you might want to let the motor hold position for a while

to see how hot the motor and the Tic get. Unlike a DC motor, stepper motors consume power and

generate heat while they are not moving. After your system heats up and reaches a steady state, if

the motor or the Tic are hotter than you would like them to be, you might consider lowering the current

limit.

Warning: This product can get hot enough to burn you long before the chips overheat. Take

care when handling this product and other components connected to it.

Setting the step mode

The “Step mode” setting controls the microstepping resolution of the Tic. The default setting of “Full

step” means that the same amount of current is always flowing through both coils (approximately 70%

of the set current limit), and every time the Tic takes a step, it will reverse the current in one of the

coils. There are only four possible coil current states in full-stepping mode, as shown in the diagram

below, and if your motor’s documentation says that it has 200 steps per revolution, that means that it

4. Setting up the controller Page 26 of 150