Pololu Tic 36v4 USB Multi-Interface High-Power Stepper Motor Controller (Connectors Soldered), Tic 36v4 USB Multi-Interface High-Power Stepper Motor Controller User manual

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Tic Stepper Motor Controller

User’s Guide

https://www.pololu.com/docs/0J71/all Page 1 of 212

1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.1. Available versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.2. Supported operating systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2. Contacting Pololu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3. Getting started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.1. Installing Windows drivers and software . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.2. Installing Linux software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3.3. Installing macOS software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3.4. LED feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4. Setting up the controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.1. Choosing the power supply, Tic, and stepper motor . . . . . . . . . . . . . . . . . . . . 28

4.2. Connecting the stepper motor and power supply . . . . . . . . . . . . . . . . . . . . . 31

4.3. Configuring and testing the stepper motor . . . . . . . . . . . . . . . . . . . . . . . . 34

4.4. Setting up USB control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

4.5. Setting up serial control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

4.6. Setting up I²C control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

4.7. Setting up RC position control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.8. Setting up RC speed control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

4.9. Setting up analog position control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

4.10. Setting up analog speed control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

4.11. Setting up encoder position control . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

4.12. Setting up encoder speed control . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

4.13. Setting up STEP/DIR control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

4.14. Setting up limit switches and homing . . . . . . . . . . . . . . . . . . . . . . . . . . 67

5. Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

5.1. Motion parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

5.2. Analog/RC input handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

5.3. Encoder input handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

5.4. Error handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

5.5. Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

5.6. Homing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

5.7. Upgrading firmware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

5.8. Logic power output (5V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

5.9. Hardware design files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

6. Setting reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

7. Variable reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

8. Command reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

9. Serial command encoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

10. I²C command encoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

11. USB command encoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

Page 2 of 212

12. Writing PC software to control the Tic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

12.1. Example code to run ticcmd in C . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

12.2. Example code to run ticcmd in Ruby . . . . . . . . . . . . . . . . . . . . . . . . . . 186

12.3. Example code to run ticcmd in Python . . . . . . . . . . . . . . . . . . . . . . . . . 188

12.4. Running ticcmd with Windows shortcuts . . . . . . . . . . . . . . . . . . . . . . . . 190

12.5. Example serial code for Linux and macOS in C . . . . . . . . . . . . . . . . . . . . 193

12.6. Example serial code for Windows in C . . . . . . . . . . . . . . . . . . . . . . . . . 197

12.7. Example serial code in Python . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

12.8. Example I²C code for Linux in C . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

12.9. Example I²C code for Linux in Python . . . . . . . . . . . . . . . . . . . . . . . . . 206

12.10. Example code using the C API . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

12.11. Example code using the C++ API . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

Page 3 of 212

1. Overview

The Tic stepper motor controllers are a family of versatile, general-purpose modules designed to

control one bipolar stepper motor [https://www.pololu.com/category/87/stepper-motors]. With a variety of

supported interfaces–USB for direct connection to a computer, TTL serial and I²C for use with a

microcontroller, RC hobby servo pulses for use in an RC system, analog voltages for use with a

potentiometer or analog joystick, and quadrature encoder for use with a rotary encoder dial–and a

wide array of configurable settings, the Tic controllers make it easy to add basic control of a bipolar

stepper motor to a variety of projects. A free configuration utility (for Windows, Linux, and macOS)

simplifies initial setup of the device and allows for in-system testing and monitoring of the controller via

USB.

1. Overview Page 4 of 212

The Tic T500, shown above, is based on the MP6500 IC from Monolithic Power Systems (MPS). This

driver IC supports microstepping with up to 8 microsteps per full step and features automatic decay

mode selection, using internal current sensing to automatically adjust the decay mode as necessary

to provide the smoothest current waveform. The Tic T500 can operate from 4.5 V to 35 V and features

reverse-protection over the full input voltage range. It can deliver up to approximately 1.5 A continuous

per phase without a heat sink or forced air flow (the peak current per phase is 2.5 A). The Tic T500’s

circuit board is red with white labels.

Powering the Tic T500 with a supply voltage between 4.5 V and 5.5 V might cause its

logic voltage to be lower than normal, which could affect its operation. See Section 4.1

for more information.

1. Overview Page 5 of 212

The Tic T834, shown above, is based on the DRV8834 IC from Texas Instruments. This driver IC

supports microstepping with up to 32 microsteps per full step and features five configurable decay

modes. The Tic T834 can operate from 2.5 V to 10.8 V and features reverse-voltage protection over

the full input voltage range. It can deliver up to approximately 1.5 A per phase without a heat sink or

forced air flow (absolute maximum is 2 A per phase). The Tic T834’s circuit board is white with black

labels.

The Tic T825, shown above, is based on the DRV8825 IC from Texas Instruments. This driver IC

supports microstepping with up to 32 microsteps per full step and features three configurable decay

1. Overview Page 6 of 212

modes. The Tic T825 can operate from 8.5 V to 45 V and features reverse-voltage protection up to

40 V. It can deliver up to approximately 1.5 A per phase without a heat sink or forced air flow (absolute

maximum is 2.5 A per phase). The Tic T825’s circuit board is blue with white labels.

The Tic T249, shown above, is based on the TB67S249FTG IC from Toshiba. This driver IC supports

microstepping with up to 32 microsteps per full step and offers several unique and innovative features.

One of these is Toshiba’s Active Gain Control (AGC), which automatically reduces the stepper motor

current below the set limit based on the actual load on the motor, allowing for reduced unnecessary

heat generation and higher peak power when the motor actually needs it. Another is Toshiba’s

Advanced Dynamic Mixed Decay (ADMD) technology, which dynamically switches between slow and

fast decay modes based on the actual motor current, providing higher efficiency and smoother steps

at high speed than you get with the traditional timing-based mixed decay. The Tic T249 can operate

from 10 V to 47 V and features reverse-voltage protection up to 40 V. It can deliver up to approximately

1.8 A per phase without a heat sink or forced air flow (absolute maximum is 4.5 A per phase). The Tic

T249’s circuit board is black with white labels.

1. Overview Page 7 of 212

The Tic 36v4, shown above, is based on a discrete MOSFET stepper motor driver that supports

microstepping with up to 256 microsteps per full step and features six configurable decay modes,

including an automatic mixed decay mode. The Tic 36v4 can operate from 8 V to 50 V and features

reverse-voltage protection up to 40 V. It can deliver up to approximately 4 A per phase without a heat

sink or forced air flow (up to 6 A per phase with sufficient additional cooling). The Tic 36v4’s circuit

board is green with white labels.

The table below lists the members of the Tic family and shows the key differences between them.

1. Overview Page 8 of 212

Tic T500 Tic T834 Tic T825 Tic T249 Tic 36v4

Operating voltage range:

Max continuous current per phase (no additional cooling):

Peak current per phase (additional cooling required):

Microstep resolutions:

Automatic decay selection:

Automatic gain control (AGC):

Driver IC: MP6500 DRV8834 DRV8825 TB67S249FTG discrete MOSFETs

Price (connectors not soldered):

Price (connectors soldered):

4.5 V to 35 V

1.5 A 1.5 A 1.5 A 1.8 A 4 A

2.5 A 2 A 2.5 A 4.5 A 6 A

$19.95 $29.95 $29.95 $39.95 $49.95

$21.95 $31.95 $31.95 $41.95 $51.95

full half 1/4 1/8

(1)

2.5 V to 10.8 V

full half 1/4 1/8

1/16 1/32

8.5 V to 45 V

full half 1/4 1/8

1/16 1/32

(1)

10 V to 47 V

full half 1/4 1/8

1/16 1/32

(1)

8 V to 50 V

full half 1/4 1/8

1/16 1/32

1/64 1/128 1/256

(1)

1 See product pages and user’s guide for operating voltage limitations.

Features and specifications

1. Overview Page 9 of 212

Tic T500 USB Multi-Interface Stepper Motor

Controller, bottom view with dimensions. This

picture shows the original tic03a version that

shipped prior to 3 January 2019.

Tic T834 USB Multi-Interface Stepper Motor

Controller, bottom view with dimensions.

Tic T825 USB Multi-Interface Stepper Motor

Controller, bottom view with dimensions.

1. Overview Page 10 of 212

• Open-loop speed or position control of

one bipolar stepper motor

• A variety of control interfaces:

◦ USB for direct connection to a

computer

◦ TTL serial operating at 5 V for

use with a microcontroller

◦ I²C for use with a

microcontroller

◦ RC hobby servo pulses for

use in an RC system

◦ Analog voltage for use with

a potentiometer or analog

joystick

◦ Quadrature encoder input

for use with a rotary encoder

dial, allowing full rotation

without limits (not for position

feedback)

◦ STEP/DIR inputs for

compatibility with existing

stepper motor control

firmware

• Acceleration and deceleration limiting

• Maximum stepper speed: 50,000 steps

per second

• Very slow speeds down to 1 step every

200 seconds (or 1 step every 1428

seconds with reduced resolution).

• Selectable microstep modes up to 1/

256-step resolution:

◦ The Tic 36v4 supports full-

step to 1/256-step modes

◦ The Tic T825, Tic T834, and

Tic T249 USB Multi-Interface Stepper Motor

Controller, bottom view with dimensions.

Tic 36v4 USB Multi-Interface High-Power Stepper

Motor Controller, bottom view with dimensions.

1. Overview Page 11 of 212

T249 support full-step to 1/32-step modes

◦ The Tic T500 supports full-step to 1/8-step modes

• Digitally adjustable current limit

• Decay modes:

◦ The Tic T500 features automatic decay mode selection.

◦ The Tic T834 features 5 digitally configurable decay modes.

◦ The Tic T825 features 3 digitally configurable decay modes.

◦ The Tic T249 features Toshiba’s Advanced Dynamic Mixed Decay (ADMD)

technology.

◦ The Tic 36v4 features 6 digitally configurable decay modes, including an automatic

mixed decay mode.

• Optional safety controls to avoid unexpectedly powering the motor

• Input calibration (learning) and adjustable scaling degree for analog and RC signals

• 5 V regulator (no external logic voltage supply needed)

• Optional limit switch inputs with homing capabilities

• Optional kill switch inputs

• STEP/DIR outputs for controlling external stepper motor drivers

• Connects to a computer through USB via a USB A to Micro-B cable [https://www.pololu.com/

product/2072] (not included)

• Free configuration software available for Windows, Linux, and macOS

1. Overview Page 12 of 212

1.1. Available versions

1. Overview Page 13 of 212

Tic T500 USB Multi-Interface Stepper

Motor Controller (Connectors

Soldered).

Tic T834 USB Multi-Interface Stepper

Motor Controller (Connectors

Soldered).

Tic T500 USB Multi-Interface Stepper Motor Controller (without connectors

soldered) with included headers and

terminal blocks.

Tic T834 USB Multi-Interface Stepper Motor Controller (without connectors

soldered) with included headers and

terminal blocks.

Tic T825 USB Multi-Interface Stepper

Motor Controller (Connectors

Soldered).

Tic T825 USB Multi-Interface Stepper Motor Controller (without connectors

soldered) with included headers and

terminal blocks.

1. Overview Page 14 of 212

Tic T249 USB Multi-Interface Stepper

Motor Controller (Connectors

Soldered).

Tic 36v4 USB Multi-Interface High-

Power Stepper Motor Controller

(Connectors Soldered).

Tic T249 USB Multi-Interface Stepper Motor Controller (without connectors

soldered) with included headers and

terminal blocks.

Tic 36v4 USB Multi-Interface High-

Power Stepper Motor Controller

(without connectors soldered) with

included headers and terminal blocks.

The Tic family consists of five different controllers: the Tic T500, Tic T834, Tic T825, Tic T249, and

Tic 36v4. The main differences between those boards are mentioned in Section 1.

Each Tic controller is each available in two versions: with terminal blocks and 0.1″ male headers

installed, as shown in the left pictures above, and with through-hole connectors included but not

soldered in, as shown in the right pictures above. The versions with connectors installed allow for all

of the main features to be used without any additional soldering required as the stepper motor and

power leads can be connected to the board via terminal blocks and the signal pins can be connected

to the board by 0.1″ connectors, such as premium jumper wires [https://www.pololu.com/category/65/

premium-jumper-wires], cables made from wires with pre-crimped terminals [https://www.pololu.com/

category/71/wires-with-pre-crimped-terminals], and servo cables [https://www.pololu.com/category/112/servo-

cables]. The connector-free versions allow for custom installations, such as soldering the included 0.1″

male header pins pointing down for use in a breadboard or soldering wires directly to the board.

1. Overview Page 15 of 212

• Tic T500 with terminal blocks and 0.1″ male headers installed [https://www.pololu.com/

product/3134]

• Tic T500 with through-hole connectors included but not soldered in

[https://www.pololu.com/product/3135]

• Tic T834 with terminal blocks and 0.1″ male headers installed [https://www.pololu.com/

product/3132]

• Tic T834 with through-hole connectors included but not soldered in

[https://www.pololu.com/product/3133]

• Tic T825 with terminal blocks and 0.1″ male headers installed [https://www.pololu.com/

product/3130]

• Tic T825 with through-hole connectors included but not soldered in

[https://www.pololu.com/product/3131]

• Tic T249 with terminal blocks and 0.1″ male headers installed [https://www.pololu.com/

product/3138]

• Tic T249 with through-hole connectors included but not soldered in

[https://www.pololu.com/product/3139]

• Tic 36v4 with terminal blocks and 0.1″ male headers installed [https://www.pololu.com/

product/3140]

• Tic 36v4 with through-hole connectors included but not soldered in

[https://www.pololu.com/product/3141]

• Three 2-pin 3.5mm screw terminal blocks [https://www.pololu.com/product/2444] – you can

combine these by sliding them together and use them with the larger motor and power holes.

• 1×10 breakaway male header pin strip [https://www.pololu.com/product/965] – this matches the

10 holes along the side of the board opposite the power and motor connections.

• 1×12 breakaway male header pin strip [https://www.pololu.com/product/965] – this can be

broken into smaller pieces and used with the other 0.1″ holes on the board as desired.

The connector-free versions include the following connectors:

1.2. Supported operating systems

We support using the Tic Stepper Motor Controller and its configuration software on Windows 7,

Windows 8, Windows 10, Linux, and macOS. The Tic’s software is not likely to work on Windows 10

IoT Core, which is very different from the normal desktop versions of Windows. The software is open

source [https://github.com/pololu/pololu-tic-software], so it could be ported to more platforms.

1. Overview Page 16 of 212

2. Contacting Pololu

We would be delighted to hear from you about any of your projects and about your experience with

the Tic Stepper Motor Controller. You can contact us [https://www.pololu.com/contact] directly or post on

our forum [https://forum.pololu.com/]. Tell us what we did well, what we could improve, what you would

like to see in the future, or anything else you would like to say!

2. Contacting Pololu Page 17 of 212

1. Download and install the Tic Software and Drivers for Windows [https://www.pololu.com/file/

0J1325/pololu-tic-1.8.0-win.msi] (10MB msi).

2. During the installation, Windows will ask you if you want to install the drivers. Click “Install” to

proceed.

3. After the installation has completed, plug the Tic into your computer via USB. Windows

should recognize the Tic and load the drivers that you just installed.

4. Open your Start Menu and search for “Tic”. Select the “Tic Control Center” shortcut (in the

Pololu folder) to launch the software.

5. In the upper left corner of the software, where it says “Connected to:”, make sure that it shows

something like “#01234567 T825”. This indicates the serial number and model of the Tic that

the software has connected to. If it says “Not connected”, see the troubleshooting section

below.

• The Pololu Tic Control Center is a graphical user interface (GUI) for configuring the Tic,

viewing its status, and controlling it manually. You can find the configuration utility in your

Start Menu by searching for it or looking in the Pololu folder.

• The Pololu Tic Command-line Utility (ticcmd) is a command-line utility that can do most of

what the GUI can do, and more. You can open a Command Prompt and type ticcmd with no

arguments to a see a summary of its options.

3. Getting started

3.1. Installing Windows drivers and software

To install the drivers and software for the Tic on a computer running Microsoft Windows, follow these

steps:

The Tic’s USB interface implements Microsoft OS 2.0 Descriptors, so it will work on

Windows 8.1 or later without needing any drivers. The driver we provide is needed for

earlier versions of Windows.

This Tic software consists of two programs:

The source code for the software [https://github.com/pololu/pololu-tic-software] is available.

USB troubleshooting for Windows

If the Tic software did not connect to the Tic, try opening the “Connected to:” drop-down box to see

if there are any entries in the list. If there is an entry, you can select it to connect to it. If there are

no entries, then the tips here can help you troubleshoot the Tic’s USB connection on a Windows

3. Getting started Page 18 of 212

computer.

If you have connected any electronic devices to your Tic besides the USB cable, you should

disconnect them.

You should look at the LEDs of the Tic. If the LEDs are off, then the Tic is probably not receiving power

from the USB port. If the green LED is flashing very briefly once per second, then the Tic is receiving

power from USB, but it is not receiving any data. These issues can be caused by using a broken USB

port, using a broken USB cable, or by using a USB charging cable that does not have data wires.

Using a different USB port and a different USB cable, both of which are known to work with other

devices, is a good thing to try. Also, if you are connecting the Tic to your computer via a USB hub, try

connecting it directly.

If the Tic’s green LED is on all the time or flashing slowly, but you can’t connect to it in the Tic software,

then there might be something wrong with Windows. A good thing to try is to unplug the Tic from USB,

reboot your computer, and then plug it in again.

If that does not help, you should go to your computer’s Device Manager and locate all the entries for

the Tic. If the Tic’s main USB driver is working, you should see an entry in the “Universal Serial Bus

devices” category called “Pololu Tic T825”. If it has a yellow triangle displayed over its icon, you should

double click on the entry to get information about the error that is happening. If you do not see that

entry, then you should open the “View” menu and select “Devices by connection”. Then expand the

entries until you find your computer’s USB controllers, hubs, and devices. See if there are any entries

in the USB area that disappear when you unplug the Tic. This might give you important information

about what is going wrong.

Do not attempt to fix driver issues in your Device Manager using the “Add legacy hardware” option.

This is only for older devices that do not support Plug-and-Play, so it will not help. If you already tried

this option, we recommend unplugging the Tic from USB and then removing any entries you see for

the Tic by right-clicking on them and selecting “Uninstall”. Do not check the checkbox that says “Delete

the driver software for this device”.

3. Getting started Page 19 of 212

1. Download the version for your system from this list:

◦ Tic Software for Linux (x86) [https://www.pololu.com/file/0J1348/pololu-tic-1.8.0-linux-

x86.tar.xz] (8MB xz) — works on 32-bit and 64-bit systems

◦ Tic Software for Linux (Raspberry Pi) [https://www.pololu.com/file/0J1349/pololu-

tic-1.8.0-linux-rpi.tar.xz] (6MB xz) — works on the Raspberry Pi and might work on

other ARM Linux systems

2. In a terminal, use cd to navigate to the directoy holding the downloaded file. For example,

run cd ~/Downloads if it was downloaded to the “Downloads” folder in your home directory.

3. Run tar -xvf pololu-tic-*.tar.xz to extract the software. If you downloaded multiple

versions of the software, you should use an exact file name instead of an asterisk.

The Status tab of the Pololu Tic Control Center.

3.2. Installing Linux software

To install the software for the Tic on a computer running Linux, follow these steps:

3. Getting started Page 20 of 212

4. Run sudo pololu-tic-*/install.sh to install the software. You will need to have sudo

privilege on your system and you might need to type your password at this point. Look at the

output of the script to see if any errors happened.

5. After the installation has completed, plug the Tic into your computer via USB. If you already

connected the Tic earlier, unplug it and plug it in again to make sure the newly-installed udev

rules are applied.

6. Run ticcmd --list to make sure the software can detect the Tic. This command should

print the serial number and model of the Tic. If it prints nothing, see the “USB troubleshooting

for Linux” section below.

7. Run ticgui to start the Tic Control Center.

• The Pololu Tic Control Center (ticgui) is a graphical user interface (GUI) for configuring the

Tic, viewing its status, and controlling it manually. You can open a terminal and type ticgui

to run it.

• The Pololu Tic Command-line Utility (ticcmd) is a command-line utility that can do most of

what the GUI can do, and more. You can open a terminal and type ticcmd with no arguments

to a see a summary of its options.

This Tic software consists of two programs:

No special drivers are needed for the Tic on Linux. Also, the Tic software is statically compiled; it does

not depend on any shared libraries.

The source code for the software [https://github.com/pololu/pololu-tic-software] is available.

Software installation troubleshooting for Linux

If you do not have sudo privilege or you do not remember your password, you can skip running

install.sh and just run the Tic programs directly from the directory you extracted them to. For

example, try running pololu-tic/ticgui after running the tar command above. You should also

consider moving the software to a more permanent location and adding that location to your PATH as

described below.

If you get a “No such file or directory” error while running ./install.sh , it is possible that your

system is missing one of the directories that the install script assumes will be present. Please contact

[https://www.pololu.com/contact] us to let us know about your system so we can consider supporting it

better in the future.

If you get the error “command not found” when you try to run ticcmd or ticgui , then you should run

echo $PATH to see what directories are on your PATH, and then make sure one of those directories

3. Getting started Page 21 of 212

contains the Tic executables or symbolic links to them. The installer puts symbolic links in /usr/local/

bin , so if that directory is not on your PATH, you should run export PATH=$PATH:/usr/local/bin to

add it. Also, you might want to put that line in your ~/.profile file so the directory will be on your

PATH in future sessions.

If you get the error “cannot execute binary file: Exec format error” when you try to run ticcmd

or ticgui , then it is likely that you downloaded the wrong version of the software from the list

above. If all of the listed versions give you this error, you will probably need to compile the software

from source by following the instructions in BUILDING.md [https://github.com/pololu/pololu-tic-software/

blob/master/BUILDING.md] in the source code [https://github.com/pololu/pololu-tic-software]. Please contact

[https://www.pololu.com/contact] us to let us know about your system so we can consider supporting it

better in the future.

If the Tic Control Center window is too big to fit on your screen properly, try setting the TICGUI_COMPACT

environment variable to Y before running the software. You can do this by running the command

TICGUI_COMPACT=Y ticgui in your terminal. You could also add the line export TICGUI_COMPACT=Y to

your ~/.profile file to make the change permanent.

If the text in the Tic Control Center window is not visible, make sure that the .ttf font file that we ship

with the software is in the same directory as the ticgui executable.

USB troubleshooting for Linux

If the Tic software cannot connect to your Tic after you plug it into the computer via USB, the tips here

can help you troubleshoot the Tic’s USB connection.

If you have connected any electronic devices to your Tic besides the USB cable, you should

disconnect them.

You should look at the LEDs of the Tic. If the LEDs are off, then the Tic is probably not receiving power

from the USB port. If the green LED is flashing very briefly once per second, then the Tic is receiving

power from USB, but it is not receiving any data. These issues can be caused by using a broken USB

port, using a broken USB cable, or by using a USB charging cable that does not have data wires.

Using a different USB port and a different USB cable, both of which are known to work with other

devices, is a good thing to try. Also, if you are connecting the Tic to your computer via a USB hub, try

connecting it directly.

If the Tic’s green LED is on all the time or flashing slowly, but you can’t connect to it in the Tic software,

then there might be something wrong with your computer. A good thing to try is to unplug the Tic from

USB, reboot your computer, and then plug it in again.

If you get a “Permission denied” error when trying to connect to the Tic, you should make sure to copy

3. Getting started Page 22 of 212

1. Download the Tic Software for macOS [https://www.pololu.com/file/0J1402/pololu-

tic-1.8.0-macos.pkg] (8MB pkg).

2. Double-click on the downloaded file to run it, and follow the instructions.

• The Pololu Tic Control Center (ticgui) is a graphical user interface (GUI) for configuring the

Tic, viewing its status, and controlling it manually. You can run it by double-clicking on “Pololu

Tic Stepper Motor Controller” in your “Applications” folder, or by opening a Terminal and

typing ticgui .

• The Pololu Tic Command-line Utility (ticcmd) is a command-line utility that can do most of

what the GUI can do, and more. You can open a terminal and type ticcmd with no arguments

to see a summary of its options.

the 99-pololu.rules file into /etc/udev/rules.d and then unplug the Tic and plug it back in again.

The install script normally takes care of installing that file for you.

If that does not help, you should try running lsusb to list the USB devices recognized by your

computer. Look for the Pololu vendor ID, which is 1ffb. You should also try running dmesg right after

plugging in the Tic to see if there are any messages about it.

3.3. Installing macOS software

To install the software for the Tic on a computer running macOS, follow these steps:

This Tic software consists of two programs:

The source code for the software [https://github.com/pololu/pololu-tic-software] is available.

Software installation troubleshooting for macOS

If you get the error “command not found” when you try to run ticcmd or ticgui , then you should try

starting a new Terminal window. The installer for the Tic software adds a file named 99-pololu-tic in

the /etc/paths.d directory to make sure the Tic software gets added to your PATH, but the change

will not take effect until you open a new Terminal window.

If the Tic Control Center window is too big to fit on your screen properly, try setting the TICGUI_COMPACT

environment variable to Y before running the software. You can do this by running the command

TICGUI_COMPACT=Y ticgui in the Terminal. You could also add the line export TICGUI_COMPACT=Y to

your ~/.profile file to make the change permanent.

USB troubleshooting for macOS

If the Tic software cannot connect to your Tic after you plug it into the computer via USB, the tips here

3. Getting started Page 23 of 212

• If the stepper motor coils are energized (i.e. electrical current is flowing), then the yellow LED

will be on solid most of the time.

◦ If the motor is moving forward (i.e. the current velocity is positive), the yellow LED

will fade in for 0.5 s and then stay on at full brightness for 0.5 s:

can help you troubleshoot the Tic’s USB connection.

If you have connected any electronic devices to your Tic besides the USB cable, you should

disconnect them.

You should look at the LEDs of the Tic. If the LEDs are off, then the Tic is probably not receiving power

from the USB port. If the green LED is flashing very briefly once per second, then the Tic is receiving

power from USB, but it is not receiving any data. These issues can be caused by using a broken USB

port, using a broken USB cable, or by using a USB charging cable that does not have data wires.

Using a different USB port and a different USB cable, both of which are known to work with other

devices, is a good thing to try. Also, if you are connecting the Tic to your computer via a USB hub, try

connecting it directly.

If the Tic’s green LED is on all the time or flashing slowly, but you can’t connect to it in the Tic software,

then there might be something wrong with your computer. A good thing to try is to unplug the Tic from

USB, reboot your computer, and then plug it in again.

Another thing to try is to run dmesg right after plugging in the Tic to see if there are any messages

about it.

3.4. LED feedback

The Tic Stepper Motor Controller has three LEDs to indicate its status.

The green LED indicates the USB status of the device. When you connect the Tic to a computer via a

USB cable, the green LED will start blinking slowly. The blinking continues until the Tic gets a particular

message from the computer that indicates that the Tic is recognized. After the Tic gets that message,

the green LED will be on, but it will flicker briefly when there is USB activity. During suspend mode (i.e.

when the Tic is only powered from USB and the computer has gone to sleep), the green LED will blink

very briefly once per second.

The red LED indicates that an error is happening. The red LED is tied to the ERR pin. For more

information about error handling, see Section 5.4.

The yellow LED indicates the status of the stepper motor and also gives some information about what

errors are happening, if there are errors:

3. Getting started Page 24 of 212

◦ If the motor is moving in reverse, the yellow LED will fade out for 0.5 and then turn

on at full brightness for 0.5 s:

◦ If the motor is energized, but not moving, and there are no errors, the yellow LED

will turn on at full brightness:

◦ If the motor is energized and there is any error happening other than a safe start

violation, the yellow LED will stay on most of the time, but will periodically blink off

twice:

◦ If the motor is energized and a safe start violation is only error happening, then the

yellow LED will stay on most of the time, but will periodically blink off once:

• If the stepper motor coils are de-energized, then the yellow LED will be off most of the time.

◦ If there is a motor driver error (i.e. from an over-current or over-temperature

condition), the yellow LED will blink 8 times per second:

This blinking will look very similar to the abnormal startup blinking described below,

so if you see it, then it is best to look at the Tic’s status using the Tic Control Center

software to figure out what is happening.

◦ If there is no motor power supplied to VIN, or the voltage is too low, the yellow LED

will blink slowly once per second (on for 0.5 s, off for 0.5 s):

3. Getting started Page 25 of 212

◦ Otherwise, if the motor has been intentionally de-energized by receiving the De-

energize command over USB, serial, or I²C, then the yellow LED will be off most of

the time, but periodically blink three times:

◦ Otherwise, if the motor is de-energized and any error is happening other than a safe

start violation, then the yellow LED will be off most of the time, but periodically blink

two times:

◦ If the motor is de-energized and the only error is a safe start violation, then the

yellow LED will be off most of the time, but periodically blink once:

Note that the Tic does not read any feedback from the motor so it cannot tell if the stepper motor is

moving, or if it is even connected. The LED blinking patterns above are based on the signals that the

Tic is sending to the on-board stepper motor driver.

To ensure that the Tic shows a complete blinking pattern instead of switching quickly between two or

more patterns, the yellow LED blinking pattern is only updated after it has completed. So if you make

a change to your system, you might have to wait for one or two seconds to see the LEDs respond.

The information expressed by the Tic’s LEDs can also be seen by connecting the Tic to a computer

via USB, running the Tic Control Center, and looking in the Status tab.

Startup blinking

When the Tic starts running, it tries to detect if it was reset by some special condition. If the

Tic experiences a brown-out reset, watchdog timer reset, software reset, stack overflow, or stack

underflow, the Tic will blink its yellow LED eight times over a one second period while the red LED is

on at startup. While it is doing this blinking, the Tic will not accept any commands, read any inputs, or

energize the stepper motor. You can see the cause of the last reset in the Tic Control Center software’s

“Last reset” field. This startup blinking was added in firmware version 1.02.

3. Getting started Page 26 of 212

Bootloader mode

In bootloader mode, which is used for updating the firmware of the Tic and should only rarely be

needed, the LEDs behave differently. The green LED still indicates the USB status, but it is different:

after the bootloader gets a particular message from the computer that indicates that the bootloader

is recognized, the green LED will start doing a double blinking pattern every 1.4 seconds. The yellow

LED will usually be on solid, but it will blink quickly whenever a USB command is received. The red

LED will be on if and only if there is no firmware currently loaded on the device.

3. Getting started Page 27 of 212

4. Setting up the controller

4.1. Choosing the power supply, Tic, and stepper motor

The information in this section can help you select a power supply [https://www.pololu.com/category/

84/regulators-and-power-supplies], a Tic controller, and a stepper motor [https://www.pololu.com/category/87/

stepper-motors] that will work well together.

Stepper motor configurations

There are different types of stepper motors. The Tic is designed to work with two-phase stepper motors

that can be connected in a bipolar configuration. The following diagram shows examples of such

stepper motors:

The Tic works with two-phase stepper motors that can be controlled in a bipolar

Your stepper motor should have one of the configurations shown above, or else it might not work with

the Tic. The next section [https://www.pololu.com/docs/0J71/4.2] explains how to connect these stepper

motors to your Tic.

configuration.

Voltage and current ratings

When selecting your power supply, Tic controller, and stepper motor, you must consider the voltage

and current ratings of each.

The voltage range of your power supply is the range of voltages you expect your power supply to

produce while operating. There is usually some variation in the output voltage so you should treat it as

a range instead of just a single number. In particular, keep in mind that a fully-charged battery might

have a voltage that is significantly higher than its nominal voltage.

The current limit of a power supply is how much current the power supply can provide. Note that the

power supply will not force this amount of current through your system; the properties of the system

and the voltage of the power supply determine how much current will flow, but there is a limit to how

much current the power supply can provide.

4. Setting up the controller Page 28 of 212

1. The voltage of your power supply should be greater than or equal to the rated voltage of your

stepper motor. Otherwise, the motor will not receive its full rated current and you will not get

the full performance that the motor is capable of. It is OK for the power supply voltage to

be higher than the rated voltage of the motor because the Tic has active current limiting. (It

rapidly switches the power to the motor on and off while measuring the current to make sure

The operating voltage range of a Tic is the range of voltages from which it can be powered. The

operating voltages of the different Tic controllers are shown in the table below. The Tic requires a DC

power supply.

The continuous current per phase of a Tic is the maximum amount of current that the Tic can

continuously provide to each phase of the stepper motor. The continuous current per phase of the

different Tic controllers are shown in the table below.

Tic T500 Tic T834 Tic T825 Tic T249 Tic 36v4

Operating voltage range:

Continuous current per phase:

4.5 V to 35 V

1.5 A 1.5 A 1.5 A 1.8 A 4 A

2.5 V to

10.8 V

8.5 V to 45 V

10 V to

47 V

8 V to 50 V

Note: While the Tic T500 can operate down to 4.5 V, power supply voltages under 5.5

V could cause a drop in the logic voltage of the board, potentially down to around 4 V

when the power supply is 4.5 V. This logic voltage drop causes the Tic’s VIN voltage

measurements to become inaccurate (too high). If you are connecting analog voltages

powered from an external source to the Tic, the lower logic voltage will cause the Tic’s

analog readings to rise and possibly require recalibration. The logic voltage drop should

not affect a potentiometer that is connected to the Tic in the standard way using the

GND, SDA/AN, and SCL pins, since the voltage on the potentiometer output will drop by

the same percentage as the Tic’s logic voltage.

The rated current of a stepper motor is the maximum amount of current that the stepper motor was

designed to have flowing through each phase, and this is typically the current required to achieve the

stepper motor’s published performance specifications.

The rated voltage of a stepper motor is how much voltage needs to be applied to a coil of

the stepper motor to get the rated current to flow through it. Ohm’s law [https://en.wikipedia.org/wiki/

Ohm%27s_law] provides the simple relationship between the rated voltage and the rated current: the

rated voltage is equal to the rated current multiplied by the coil resistance.

These are the main constraints you should keep in mind when selecting your power supply, Tic

controller, and stepper motor:

4. Setting up the controller Page 29 of 212

it does not go too high.)

2. A higher power supply voltage is usually desirable since it allows higher speed and torque.

However, if the power supply voltage is extremely high compared to the stepper motor’s rated

voltage and you want to use microstepping, you might experience skipped steps.

3. The voltage of your power supply should be within the operating voltage range of the Tic.

Otherwise, the Tic could malfunction or (in the case of high voltages) be damaged.

4. The continuous current per phase of the Tic should be greater than or equal to the rated

current of the stepper motor. Otherwise, the Tic will not be able to deliver the full rated

current to the motor and you will not get the full performance that your motor is capable of.

(However, if you are using USB, serial, or I²C to control the Tic, you might be able to get

better performance out of the Tic by dynamically increasing the current limit above the Tic’s

continuous current rating whenever you move the motor, and reducing it while the motor

is holding position, thus maintaining a low average current.) If the motor’s rated current is

substantially more than the Tic’s current, then it is possible that the Tic will not be able to

move the motor at all.

5. We generally recommend you choose a power supply with a current limit that is at least at

least twice the current limit you are planning to use on the Tic as that amount of current

should always be safely beyond what the Tic will draw. The current limit you configure on the

Tic should generally not exceed the stepper motor’s rated current and should not exceed the

continuous current per phase of the Tic. So if you take the smaller of those two currents, and

then multiply that current by two, and get a power supply that can provide at least the much

current, you can be sure that the power supply’s current will not be the limiting factor in your

application. However, please note that you can typically get by with less power supply current

than this, especially if your supply voltage is higher than the rated voltage of your stepper

motor. In this situation, the Tic’s current control acts as a step-down converter, meaning that

a small amount of current from the power supply at a higher voltage can generate a larger

amount of current going through the coils at a lower voltage. Also, most Tic controllers never

actually drive both coils at the configured current limit at the same time. The total current

going through the coils is maximized in the four full-step positions, where the Tic will be

sending 71% of the current limit through each coil, for a total current of 142% of the current

limit. (The Tic T249 is the only exception; it has two step modes where it will send the full

configured current into both coils at the same time.) If you want to know the maximum current

draw from your power supply, you can measure this with a multimeter while the stepper motor

is energized in full-step mode and not stepping. If your system draws too much current, your

power supply might shut down, overheat, produce a lower voltage, and/or be damaged.

4. Setting up the controller Page 30 of 212

It is worth noting again that since the Tic actively limits current through the motor coils,

you can safely use power supplies with voltages above the rated voltage of the stepper

motor as long as you set the current limit to not exceed the stepper motor’s rated current.

For example, this means that the Tic T825 (which has a minimum operating voltage

of 8.5 V) can be used with a stepper motor rated for 3.2 V if the current limit is set

appropriately.

4.2. Connecting the stepper motor and power supply

The information in this section can help you connect your stepper motor and power supply to the Tic.

To avoid damage or injury, please read these safety warnings carefully:

Warning: This product is not designed to or certified for any particular high-voltage safety

standard. Working with voltages above 30 V can be extremely dangerous and should only

be attempted by qualified individuals with appropriate equipment and protective gear.

Warning: Connecting or disconnecting a stepper motor while the Tic’s motor power supply

(VIN) is powered can destroy the motor driver. (More generally, rewiring anything while it is

powered is asking for trouble.)

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.

Before connecting anything to the Tic, we recommend running the Tic Control Center software to make

sure it can connect to the Tic over USB. This way you can ensure that the Tic is functioning before you

spend time soldering connectors or connecting other electronics, and if something goes wrong, you

will have a better idea of what caused the problem.

4. Setting up the controller Page 31 of 212

Connecting a bipolar stepper motor with four or six leads

Bipolar stepper motors commonly have four or six leads. These two-phase stepper motors have one

coil per phase, with one lead connected to each end of each coil. Versions with six leads also provide

access to the centers of the two coils so that the motor can optionally be controlled by a unipolar driver.

When controlling a six-lead stepper motor with a bipolar driver like the Tic, only the ends of the coils

are used, and the two center tap leads should be left disconnected.

4. Setting up the controller Page 32 of 212

Connecting a two-phase bipolar stepper

motor with four (4) leads to the Tic.

Connecting a two-phase unipolar/

bipolar stepper motor with six (6) leads

to the Tic. The two center taps are left

disconnected.

Swapping A1 with A2 or B1 with B2 in the above diagrams just reverses the direction of

the motor. Swapping both will leave the direction unchanged.

Connecting a bipolar stepper motor with eight leads

Unlike four- and six-lead stepper motors, which have a single coil per phase, eight-lead unipolar/

bipolar stepper motor have two coils per phase and give you access to all of the coil leads. You have

the option of using the two coils for each phase in parallel or in series.

When using them in parallel, you decrease coil inductance, which can lead to increased performance

if you have the ability to deliver more current. However, since the Tic actively limits the output current

per phase, you will only get half the phase current flowing through each of the two parallel coils. When

using the phase coils in series, it’s like having a single coil per phase (like the motor types discussed

above). We generally recommend using a series connection. The following diagram shows how to

connect such a stepper motor to the Tic with each pair of phase coils in parallel (left) or series (right):

4. Setting up the controller Page 33 of 212

Connecting a two-phase unipolar/

bipolar stepper motor with eight (8)

leads to the Tic with the phase coils in

parallel.

Connecting a two-phase unipolar/

bipolar stepper motor with eight (8)

leads to the Tic with the phase coils in

series.

Power supply

To connect your power supply to the Tic, connect the negative or ground terminal of your power supply

to the Tic’s GND pin on the high current side of the board (next to motor output A1). Then, connect

your power supply’s positive terminal to the VIN pin next to that.

4.3. Configuring and testing the stepper motor

This section explains how to configure and test your motor over USB using the Tic Control Center

software. It is a good idea to test the motor over USB like this to make sure that the motor is working

and that you can get the desired performance out of it before you connect a different kind of input to

the Tic and try to use that to control the motor.

If you have changed any of the settings of your Tic, you should probably reset the

Tic to its default settings by opening the “Device” menu and selecting “Restore default

settings”. Then, go to the “Input and motor settings” tab and make sure the “Control

mode” is set to “Serial / I²C / USB” (the default).

The Tic’s motor settings can be found in the “Motor” box. This screenshot shows the default settings

for the Tic T825:

4. Setting up the controller Page 34 of 212

The default motor settings for the Tic T825.

The different Tic models have different available step modes, current limits, and decay modes. The Tic

T249 has additional settings for configuring its Active Gain Control (AGC) feature, and the Tic 36v4

has additional settings that control various driver timing parameters, as described in Section 6.

Setting the current limit

Assuming that you are not limited by the Tic or your power supply, we recommend setting the current

limit of the Tic to the rated current of your motor. You should make sure the current limit is not higher

than what the Tic can deliver continuously, as shown in this table.

Tic T500 Tic T834 Tic T825 Tic T249 Tic 36v4

Continuous current per phase: 1500 mA 1800 mA 4000 mA

In addition, make sure the current limit is not higher than half of the rated current of your motor power

supply (though this is not always necessary and a higher current limit could work, as explained in

Section 4.1). You should also make sure that the Tic’s configured current limit never exceeds the rated

current of your stepper motor.

The current limit is specified in the Tic Control Center in units of milliamps (mA), which are one

thousandth of an amp (ampere). So if you want to set your current limit to 0.9 A, you should enter

“900” in the “Current limit” field. Note that the current limit can only be set to certain specific values.

After you type in a current limit, the control center will use the closest valid setting that is less than or

4. Setting up the controller Page 35 of 212

equal to the current limit you typed. You can use the up and down arrows to browse through the valid

current limit settings. The different Tic models have different sets of allowed current limits.

Tic 36v4 warning: The Tic 36v4 has no meaningful over-temperature shut-off (while the

gate driver IC has over-temperature protection, it is the external MOSFETs that will overheat

first). An over-temperature condition can cause permanent damage to the motor

driver. We strongly recommend you do not increase the current limit setting beyond

4000 mA (or lower in applications with reduced heat dissipation) unless you can first confirm

that the temperature of the MOSFETs will stay under 140°C. By default, the Tic will prevent

you from setting a current limit above 4000 mA, but you can override this if you check the

“Enable unrestricted current limits” checkbox.

Testing the motor for the first time

After setting the current limit, click “Apply settings”. There should be a message at the bottom of

the window that says “Motor de-energized because of safe start violation. Press Resume to start.”

Click the green “Resume” button to energize the stepper motor. If all goes well, the current you have

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, report a “Low VIN” error, and de-energize the

motor. The Low VIN threshold for each Tic is shown in this table.

Tic T834 Tic T500 Tic T249 Tic 36v4 Tic T825

Low VIN threshold: 2.1 V 3.0 V 5.5 V 5.8 V 7.0 V

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

4. Setting up the controller Page 36 of 212

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. In the “Full step” and “Full

step 100%” modes, the same amount of current is always flowing through both coils, 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 takes 200 of these full steps to rotate 360

degrees.

Allowed coil current transitions in full step mode. Arrows to the right correspond to one motor

Another way to visualize this is with a graph of the coil currents for each of the four full steps, with one

axis representing the phase (or coil) A current and the other axis representing the phase B current.

For “Full step” mode, where each coil always has approximately 70% of the configured current limit,

that graph looks like this:

4. Setting up the controller Page 37 of 212

rotation direction and arrows to the left correspond to the other.

Coil currents for the four (4) steps that make up full-step mode (I

1-4

In the other available step modes, the Tic uses microsteps instead of full steps to generate magnetic

fields that point to places between the full steps. Each microstep corresponds to 1/2, 1/4, 1/8, 1/16, 1/

32, 1/64, 1/128, or 1/256 of a full step, depending on what step mode you choose. For example, if you

choose 1/32, then it will take 32 microsteps to move the same distance as one full step, and a motor

with 200 steps per revolution will require 6400 microsteps to turn 360 degrees. The following graph

shows the coil currents for each of the microsteps in 1/4-step mode:

4. Setting up the controller Page 38 of 212

• The Tic T500 only supports full, 1/2, 1/4, and 1/8 step modes.

• The Tic T825 Tic T834, and Tic T249 support full, 1/2, 1/4, 1/8, 1/16, and 1/32 step modes.

◦ The Tic T249 supports “Full step 100%” mode instead of normal full step mode, and

it additionally supports “1/2 step 100%” mode. In these two “100%” modes, any non-

zero coil current is 100% of the rated current instead of 70% (as in the normal full

Coil currents for the 16 microsteps that make up 1/4-step mode (I

In the above graph, currents I3, I7, I11, and I15match the four full-step currents, where the magnitude

of the current through both coils is equal. All other steps point between these full steps by setting

different current limits for the two coils. The most extreme example of this occurs on steps I1, I5, I9,

and I13, where the current through one coil is equal to the full current limit setting on the Tic while the

current through the other coil is zero.

4. Setting up the controller Page 39 of 212

1-16

and 1/2 step modes). These modes are sometimes described as “non-circular”.

• The Tic 36v4 supports full, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, and 1/256 step modes.

• The Tic T825 has three decay modes: slow, mixed (default), and fast.

• The Tic T834 has five decay modes: slow, mixed 25%, mixed 50% (default), mixed 75%, and

fast.

• The Tic 36v4 has six decay modes: slow, slow / mixed, fast, mixed, slow / auto-mixed, and

auto-mixed (default).

The Tic’s speed, velocity, acceleration, and deceleration numbers are all denominated in

microsteps, which are also called pulses. Therefore, if you change the step mode, you

might have to change those other settings to account for the change. For example, the

default maximum speed for the Tic is 200 pulses per second. If you change the step

mode from full step to half step, you would have to change the speed to 400 pulses per

second to maintain the same angular rate of change. Since the step mode affects those

other parameters, it is a good idea to set it first.

Setting the decay mode (T825, T834, and 36v4 only)

The Tic T825, Tic T834, and Tic 36v4 have a decay mode setting that affects how fast current through

the motor coils decays during each step.

The decay mode matters most when microstepping is used. Which decay mode is most appropriate

depends on many factors specific to a particular stepper motor system, including the motor’s

resistance and inductance, the supplied motor voltage, and the desired speed. Generally, using slow

decay generates less electrical and audible noise, but it can result in missed microsteps when the

coil current is decreasing. Fast decay is much noisier both electrically and audibly, but it creates

more evenly sized microsteps. Mixed decay is a combination of both fast and slow decay that tries to

minimize noise while keeping microsteps as even as possible. For more information about the decay

modes and current control methods of the Tic’s stepper motor driver, refer to the DRV8825 datasheet

[https://www.pololu.com/file/0J590/drv8825.pdf] (1MB pdf) for the Tic T825 or the DRV8834 datasheet

[https://www.pololu.com/file/0J617/drv8834.pdf] (2MB pdf) for the Tic T834.

The Tic 36v4 is configured to use auto-mixed decay by default. In this mode, the driver automatically

selects slow or fast decay based on the actual motor current. This combines some of the advantages

of both slow and fast decay, and it should work well in most situations, but you can select a different

decay mode if auto-mixed is not optimal for your system. Decay modes with a slash (/) indicate

different behavior for increasing- and decreasing-current steps; for example, the “Slow / mixed” setting

uses slow decay for steps where the current increases and mixed decay where the current decreases.

4. Setting up the controller Page 40 of 212

For more information about the Tic 36v4’s decay modes, as well as the additional timing parameter

settings that can affect their operation, refer to its DRV8711 gate driver IC’s datasheet

[https://www.pololu.com/file/0J1684/drv8711.pdf] (3MB pdf) and to Section 6.

The decay mode of the Tic T500 is not configurable. The Tic T500 features automatic decay mode

selection, using internal current sensing to automatically adjust the decay mode as necessary to

provide the smoothest current waveform. For more information, see the MP6500 datasheet

[https://www.pololu.com/file/0J1447/MP6500_r1.0.pdf] (1MB pdf).

The decay mode of the Tic T249 is not configurable. The Tic T249 features Toshiba’s Advanced

Dynamic Mixed Decay (ADMD) technology, which dynamically switches between slow and fast

decay modes based on the actual motor current, providing higher efficiency and smoother steps

at high speed than you get with traditional timing-based mixed decay. For more information, see

the TB67S249FTG datasheet [https://www.pololu.com/file/0J1523/TB67S249FTG_datasheet_en_20170818.pdf]

(533k pdf).

Configuring Active Gain Control (T249 only)

The TB67S249FTG IC on the Tic T249 supports Toshiba’s Active Gain Control (AGC) feature, which

automatically reduces the stepper motor current below the set limit based on the actual load on the

motor, allowing for reduced unnecessary heat generation and higher peak power when the motor

actually needs it. The AGC feature is disabled by default, but you can enable it and configure it using

the AGC settings in the “Input and motor settings” tab. For more information about these settings, see

Section 6.

Setting the movement parameters

After you have set the motor’s step mode, current limit, decay mode, and AGC settings (if applicable),

you should set its maximum speed and maximum acceleration.

The Tic represents speeds (non-negative values indicating the magnitude of a velocity), velocities

(signed values indicating speed and direction), and speed limits in units of pulses (microsteps) per

10,000 (ten thousand) seconds. The Tic can send up to 50,000 pulses (microsteps) per second, so

the maximum allowed speed setting is 500,000,000. However, your motor might not be capable of

moving that fast. If you want to get the maximum speed possible out of your motor, you might have to

do some tests to see how fast it can go. To do this, set the max speed to 500,000,000 in the “Input and

motor settings” and click “Apply settings”. Then go to the “Set target” box in the “Status” tab, select

“Set velocity”, and enter smaller numbers in the boxes at the ends of the scroll bar that determine its

range. For example, try entering -4,000,000 and 4,000,000, which would mean the scrollbar can set

target velocities between −400 pulses per second and +400 pulses per second, as shown below.

4. Setting up the controller Page 41 of 212

The “Set target” box in the Tic Control Center, with its range set to plus or minus 400 pulses

per second.

Try slowly dragging the scrollbar to both ends of its range. If your motor is able to reach the desired

speeds without pausing or skipping, you can increase the range of the scrollbar and try again. By

experimenting with the velocity scrollbar, you should be able to get an idea of what your motor can

do. Once you have done that, go back to the “Input and motor settings” tab and set the “Max speed”

appropriately.

You will probably have to adjust the “Max acceleration” parameter too. The Tic represents acceleration

and deceleration limits in units of pulses per second per 100 seconds. The acceleration and

deceleration limits specify how much the speed (in units of 10,000 pulses per second) is allowed to

rise or fall in one hundredth of a second (0.01 s or 10 ms). To set the acceleration limit, you might

consider how much time you want the Tic to spend accelerating from rest to full speed. If you want it

to take one second, then set the maximum acceleration to be one hundredth of the maximum speed.

Unlike a DC motor, which will accelerate on its own up to some max speed when a

voltage is applied, step rates must be gradually increased by the controller if you want to

achieve high maximum speeds. If you just jump abruptly to a high step rate, the inertia of

the stationary rotor will prevent it from being able to keep up with the rotating magnetic

field and it will get left behind; the result of this is that it will just sit there or vibrate in

place (or possibly even start moving backward). The Tic’s max acceleration parameter

limits how quickly the step rates will increase, which if set correctly, will give the rotor

time to keep up with the magnetic field as it spins faster and faster (up to some maximum

speed that is ultimately a function of your specific stepper motor as well as the current

limit setting, the supply voltage, and the load on the stepper motor output).

By default, the Tic’s deceleration limit is the same as its acceleration limit. If you want the deceleration

rate to be different, you can uncheck the “Use max acceleration limit for deceleration” box.

The “Starting speed” parameter specifies a speed below which deceleration and acceleration limits

are not respected. For example, if you set the starting speed to 1000000 (100 pulses per second),

4. Setting up the controller Page 42 of 212

then the Tic will be able to instantly change from any velocity in the range of −1000000 to +1000000 to

any other velocity in that range. Setting the starting speed might allow you to make your system faster

since it will not waste time accelerating or decelerating through low speeds where it is not needed.

4.4. Setting up USB control

This section explains how to control the Tic over USB.

If you have not done so already, you should follow the instructions in Section 4.3 to configure and test

your stepper motor. You should leave your Tic’s control mode set to “Serial / I²C / USB” (the default).

That section also shows how to control the Tic over USB using the Tic Control Center software. If

the Tic Control Center’s graphical user interface is good enough for you, you do not need to set up

anything else and can skip the rest of this section.

Another option for controlling the Tic over USB is to use the Tic Command-line Utility, ticcmd . You

can either run the utility directly by typing commands in your command prompt (shell), or you can write

your own software that runs it.

To try out ticcmd , you should open a new command prompt and run ticcmd without any arguments.

This causes ticcmd to print out a help screen listing all the options it supports. You can combine

multiple options in one invocation.

If your command prompt prints out a message indicating that ticcmd is not found or not recognized,

make sure you have installed the Tic software properly as described earlier in this guide. Also, make

sure that the directory containing the ticcmd executable is in your PATH environment variable, and

try starting a new command prompt or terminal after installing the software.

To set the target position or velocity of the Tic, try running these commands:

ticcmd --exit-safe-start --position 400 ticcmd --exit-safe-start --velocity 2000000

Note: The --position option can be abbreviated as -p , and --velocity can be

abbreviated as -y .

If the commands above do not produce movement, you should run ticcmd --status to print out the

errors that are currently stopping the motor. This might tell you what is going wrong.

On Microsoft Windows, only one device can access the Tic’s USB interface at a time, so

you will need to close the Tic Control Center software before running ticcmd .

4. Setting up the controller Page 43 of 212

You might notice that the Tic only performs the desired movement for about a second before it

stops moving and the red LED turns on, indicating an error. This is because of the Tic’s command

timeout feature: by default, the Tic’s “Command timeout” error will happen if it does not receive certain

commands periodically (see Section 5.4 for details), causing the motor to stop. You can run ticcmd

--reset-command-timeout every second to get around this, or you can disable the command timeout

feature using the Tic Control Center: uncheck the “Enable command timeout” checkbox in the “Serial”

box.

To get the current status of the Tic, try running these commands, which give different levels of detail:

ticcmd --status ticcmd --status --full

The output of these commands is designed to be compatible with the YAML format, so if you are

writing a computer program that needs to get some information from the Tic, you can parse the output

with a YAML parser in the language of your choice.

If you have multiple Tics connected to the computer, you will need to use the -d option to specify

the serial number of the device you want to use. For example, to get the status of the Tic with serial

number 12345678, run ticcmd -d 12345678 --status . You can run ticcmd --list to get the serial

numbers (they are listed in the first column). If you omit the -d option, ticcmd will print: “Error: There

are multiple qualifying devices connected to this computer. Use the -d option to specify which device

you want to use, or disconnect the others.”

For more details about the commands you can send to the Tic over USB, see Section 8.

If you want to write your own software to control the Tic instead of just using ticcmd or the Tic Control

Center, see Section 12.

4.5. Setting up serial control

This section explains what kind of serial interface the Tic has and how to connect a microcontroller or

other TTL serial device to it so that you can send commands to control the Tic. The Tic Stepper Motor

Controller library for Arduino [https://github.com/pololu/tic-arduino] makes it particularly easy to control

the Tic from an Arduino or Arduino-compatible board such as an A-Star 32U4 [https://www.pololu.com/

a-star].

About the serial interface

The RX and TX pins of the Tic provide its serial interface. The Tic’s RX pin is an input, and its TX pin is

an output. Each pin has an integrated 100 kΩ resistor pulling it up to 5 V and a 220 Ω or 470 Ω series

resistor protecting it from short circuits.

4. Setting up the controller Page 44 of 212

The serial interface uses non-inverted TTL logic levels: a level of 0 V corresponds to a value of 0, and

a level of 5 V corresponds to a value of 1. The input signal on the RX pin must reach at least 4 V to be

guaranteed to be read as high, but 3.3 V signals on RX typically work anyway.

The serial interface is asynchronous, meaning that the sender and receiver each independently time

the serial bits. The sender and receiver must be configured to use the same baud rate, which is

typically expressed in units of bits per second. The data format is 8 data bits, one stop bit, with no

parity, which is often expressed as 8-N-1. The diagram below depicts a typical serial byte:

Diagram of a non-inverted TTL serial byte.

The serial lines are high by default. The beginning of a transmitted byte is signaled with a single low

start bit, followed by the bits of byte, least-significant bit (LSB) first. The byte is terminated by a stop

bit, which is the line going high for at least one bit time.

Connecting a serial device to one Tic

If you have not done so already, you should follow the instructions in Section 4.3 to configure and test

your stepper motor. You should leave your Tic’s control mode set to “Serial / I²C / USB” (the default),

and you should also set your desired baud rate.

Next, connect your serial device’s GND (ground) pin to one of the Tic’s GND pins.

If your serial device operates at 5 V, you can directly connect the device’s TX line to the Tic’s RX line

and connect the Tic’s TX line to the device’s RX line. The connection to the Tic’s TX line is only needed

if you want to read data back from the Tic. These connections, and some other optional connections,

are shown in the diagram below:

4. Setting up the controller Page 45 of 212

If your serial device operates at 3.3 V, then you might need additional circuitry to shift the voltage

levels. You can try connecting the device’s TX line directly to the Tic’s RX line; this will usually work,

but the input signal on the RX pin must reach at least 4 V to be guaranteed to be read as high. If

you want to read data from the Tic, you will need to consider how to connect the Tic’s TX line to your

device’s RX line. If your device’s RX line is 5V tolerant, meaning that it can accept a 5 V output being

applied directly to it, then you should be able to connect the Tic’s TX line directly to your device’s RX

line. If your device’s RX line is not 5V tolerant, you will need to a use a level shifter—a separate board

or chip that can convert 5 V signals down to 3.3 V. A voltage divider made with two resistors would

work too.

Whenever connecting devices, remember to wire the grounds together, and ensure that

each device is properly powered. Unpowered devices with a TTL serial port can turn on

or partially on, drawing power from the serial line, which means that extra care must be

taken when turning power off and on to reset the devices.

Note: You must use an inverter and level shifter such as a MAX232 or a Pololu 23201a

Serial Adapter [https://www.pololu.com/product/126] if you want to interface an RS-232 device

with the Tic. Connecting an RS-232 device directly to the Tic can permanently damage it.

If you are using an Arduino or Arduino-compatible board, you should now try running the

SerialSpeedControl example that comes with the Tic Arduino library. The library’s README

[https://github.com/pololu/tic-arduino] has information about how to get started and which pins of the

Arduino to use. If you are using a different kind of microcontroller board, you will need to find or write

code to control the Tic on your platform. If you are writing your own code, we recommend that you

first learn how to send and receive serial bytes on your platform, and then use the SerialSpeedControl

4. Setting up the controller Page 46 of 212

example as a reference. You should also refer to the sections in this guide about the Tic’s commands

(Section 8) and serial protocol (Section 9).

If your connections and code are OK, you should now see the Tic’s stepper motor moving back and

forth. If the stepper motor is not moving, you should check all of your connections and solder joints (if

applicable). You should make sure that the Tic and your device are configured to use the same baud

rate. The Tic uses 9600 bits per second by default. You should also check the “Status” tab of the Tic

Control Center to see if any errors are being reported.

The SerialSpeedControl example only writes data to the Tic, so it does not test your connection to

the Tic’s TX line. If you want to read data from the Tic, you should now try the SerialPositionControl

example, which reads the current position of the stepper motor from the Tic.

Optional connections

The Tic’s 5V (out) pin provides access to the output of the Tic’s 5V regulator, which also powers

the Tic’s microcontroller and the red and yellow LEDs. You can use the Tic’s regulator to power your

microcontroller or other serial device if the device does not draw too much current (see Section 5.8).

The VM pin provides access to the Tic’s power supply after the reverse-voltage protection circuit, and

this pin can be used to provide reverse-voltage-protected power to other components in the system if

the Tic supply voltage is within the operating range of those components. Note: this pin should not be

used to supply more than 500 mA; higher-current connections should be made directly to the power

supply. Unlike the 5V (out) pin described above, this is not a regulated, logic-level output.

The ERR pin of the Tic is normally pulled low, but drives high to indicate when an error is stopping

the motor. You can connect this line to an input on your microcontroller (assuming it is 5V tolerant) to

quickly tell whether the Tic is experiencing an error or not. Alternatively, you can query the Tic’s serial

interface to see if an error is happening, and which specific errors are happening. For more information

about the ERR pin, see Section 5.4.

The RST pin of the Tic is connected directly to the reset pin of the Tic’s microcontroller and also has

a 10 kΩ resistor pulling it up to 5 V. You can drive this pin low to perform a hard reset of the Tic’s

microcontroller and de-energize the stepper motor, but this should generally not be necessary for

typical applications. You should wait at least 10 ms after a reset to transmit to the Tic.

Connecting a serial device to multiple Tics

The Tic’s serial protocol is designed so that you can control multiple Tics using a single TTL serial port.

Before attempting to do this, however, we recommend that you first get your system working with just

one Tic as described above.

Next, make sure that the serial device and the Tics all share a common ground, for example by

4. Setting up the controller Page 47 of 212

connecting a GND pin from the device to a GND pin on each of the Tics. Make sure that the TX pin on

the serial device is connected to the RX pin of each Tic (via a level shifter if needed).

If you attempt to run the SerialSpeedControl example in this configuration, you should see each of your

Tic controllers moving their stepper motors in unison. That example uses the Tic’s Compact Protocol,

which is only suitable for controlling one device. The Compact Protocol commands do not contain

a device number, so every Tic device that sees a Compact Protocol command will obey it. This is

probably not what you want.

To allow independent control of multiple Tics, you should use the Tic Control Center to configure each

Tic to have a different device number. Then you should change your code to use the Pololu Protocol

as described in Section 9. If you are using our Tic Arduino library, you can declare one object for each

Tic, and specify the device number of each Tic, by writing code like this at the top of your sketch, which

uses device numbers 14 and 15:

12TicSerial tic1(ticSerial, 14);

TicSerial tic2(ticSerial, 15);

If you want to read data from multiple Tics, you cannot simply connect all of the Tic TX lines together,

because when one of Tics tries to drive its TX line low to send data, the TX lines from the other Tics

will still be driving the line high and will prevent the signal from going all the way to 0 V. Instead, you

will need to connect an external AND gate. The TX line of each Tic should be connected to an input

line of the AND gate. The output of the AND gate should be connected to the RX line of your serial

device (through a voltage divider or level shifter if necessary). The following diagram shows these

connections along with optional connections of the ERR and RST pins:

4. Setting up the controller Page 48 of 212

The ERR pins can all be safely connected together. In such a configuration, the line will be high if one

or more Tics has an error; otherwise, it will be low. Additionally, the Tics are configured by default to

treat a high signal on their ERR lines as an error, so an error on one Tic will trigger an error on all

other Tics when their ERR lines are connected as shown in the above diagram. This behavior can

be disabled by checking the “Ignore ERR line high” box under the “Advanced settings” tab of the Tic

Control Center. For more information on the ERR pin and error handling in general, see Section 5.4.

Using I²C instead of serial to read data from multiple Tics does not require an AND gate

(see Section 4.6).

More information about the serial interface

This user’s guide has more information about the Tic’s commands (Section 8) and serial protocol

(Section 9).

4.6. Setting up I²C control

This section explains how to connect a microcontroller to the Tic’s I²C interface so that you can send

commands to control the Tic. The Tic Stepper Motor Controller library for Arduino [https://github.com/

pololu/tic-arduino] makes it particularly easy to control the Tic from an Arduino or Arduino-compatible

board such as an A-Star 32U4 [https://www.pololu.com/a-star].

About the I²C interface

The SCL and SDA/AN pins of the Tic provide its I²C interface. The pins are open drain outputs,

meaning that they only drive low and they never drive high. Each pin has a 220 Ω or 470 Ω series

resistor protecting it from short circuits. By default, each pin is pulled up to 5 V by the Tic’s

microcontroller with a pull-up resistor that is typically around 40 kΩ. When the Tic is reading the SCL

or SDA pin as an input, any value over 2.1 V will be considered to be high.

Devices on the I²C bus have two roles: a master that initiates communication, and a slave that

responds to requests from a master. The Tic acts as the slave. The Tic uses a feature of I²C called

clock stretching, meaning that it holds the SCL line low to delay I²C communication while it is busy

processing data from the master.

Connecting an I²C device to one Tic

If you have not done so already, you should follow the instructions in Section 4.3 to configure and test

your stepper motor. You should leave your Tic’s control mode set to its default value of “Serial / I²C /

USB” and leave the “Device number” set to its default value of 14. The “Device number” specifies the

7-bit address for the Tic to use on the I²C bus.

4. Setting up the controller Page 49 of 212

Next, connect your device’s SCL pin to the Tic’s SCL pin, and connect your device’s SDA pin to the

Tic’s SDA pin. You should also connect your device’s GND (ground) pin to one of the Tic’s GND pins.

These connections, and some other optional connections, are shown in the diagram below:

Because the Tic considers an input value of 2.1 V on SCL or SDA to be high, you can connect

those pins directly to 3.3 V microcontrollers without needing a level shifter. If your microcontroller’s

I²C interface is not 5V tolerant, it will usually still have a diode going from each I/O pin to its logic

supply. These diodes clamp the voltage on the pins, preventing the Tic’s pull-up resistors from pulling

the pins too high. If you want to be extra safe and not rely on the clamping diodes, you can disable

the Tic’s pull-up resistors by going to the “Advanced settings” tab in the Tic Control Center, changing

the functions of SCL and SDA to “Serial”, and making sure the “Pull-up” checkbox for each pin is not

checked.

Depending on your setup, you might need to add pull-up resistors to the SCL and SDA lines of your

I²C bus to ensure that the signals rise fast enough. The Tic’s pull-up resistors are enabled by default,

and many I²C master devices will have pull-ups too, but that might not be enough, especially if you

want to use speeds faster than 100 kHz or have long wires. The I²C-bus specification and user

manual [https://www.pololu.com/file/0J435/UM10204.pdf] (1MB pdf) has some information about picking pull-

up resistors in the “Pull-up resistor sizing” section, and trying a value around 10 kΩ is generally a good

starting point.

If you are using an Arduino or Arduino-compatible board, you should now try running the

I2CSpeedControl example that comes with the Tic Arduino library [https://github.com/pololu/tic-arduino].

If you are using a different kind of microcontroller board, you will need to find or write code to control

the Tic on your platform. If you are writing your own code, we recommend that you first learn how to

use the I²C interface of your platform, and then use the I2CSpeedControl example as a reference. You

4. Setting up the controller Page 50 of 212

should also refer to the sections in this guide about the Tic’s commands (Section 8) and I²C protocol

(Section 10).

If your connections and code are OK, you should now see the Tic’s stepper motor moving back and

forth. If the stepper motor is not moving, you should check all of your connections and solder joints (if

applicable). You should check the “Status” tab of the Tic Control Center to see if any errors are being

reported. You can also try slowing down your I²C clock speed to something very slow like 1 kHz or

10 kHz. If slowing down the clock works, then the problem might be due to not having strong enough

pull-up resistors on the SDA and SCL lines.

Optional connections

The Tic’s 5V (out) pin provides access to the output of the Tic’s 5V regulator, which also powers

the Tic’s microcontroller and the red and yellow LEDs. You can use the Tic’s regulator to power your

microcontroller or another device if the device does not draw too much current (see Section 5.8).