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By Sparkfun Electronics

Hookup Guide for the Qwiic Motor Driver

Courtesy of SparkFun


The Qwiic Motor Driver takes all the great features of the Serial Controlled Motor Driver and mini-sizes them, adding Qwiic ports for plug and play functionality. Boasting the same PSOC and 2-channel motor ports, the QWIIC Motor Driver is designed to communicate over I2C, but UART is also available.


Required Materials

To follow along with this tutorial, you will need the following materials. You may not need everything though depending on what you have. Add it to your cart, read through the guide, and adjust the cart as necessary.

Qwiic Motor Driver Wish List SparkFun Wish List

Suggested Reading

If you aren’t familiar with the following concepts, we recommend you read over these tutorials before continuing.

Hardware Overview

Let's look at some of the various features of the hardware.


  • 1.5 A peak drive per channel, 1.2 A steady state
  • Operates from 3 to 11 volts with 12v absolute max
  • 3.3V default VCC and logic
  • 127 levels of DC drive strength
  • Controllable by I2C or TTL UART signals
  • Direction inversion on a per motor basis
  • Global Drive enable
  • Exposed small heat sink shape
  • Several I2C addresses, default UART bauds available



There are two separate power circuits on this board. Power for the motors is supplied through the VIN Connectors - you can provide anywhere from 3.3V to 11V to the "MAX 11V" and "GND" connections. Power for the PSOC and logic circuits is provided by the 3.3V inputs on the Qwiic connectors. Both are needed for proper functioning.


Motor Power Ports: Ground (Left) - VIN(Right)

Qwiic Connectors

There are two Qwiic connectors on the board such that you can provide power or daisy-chain the boards should you choose to do so. If you're unfamiliar with our Qwiic system, head on over to our Qwiic page to see the advantages!


Motor Ports

The screw pin terminals at the top of the board allow for two motor connections. They are labeled on the backside of the board.


From left to right on the front: B2-B1-A2-A1



Jumper Usage Table

There are 2 sets of jumpers to configure on this board. There are pull-up enables for I2C and 4 config bits that select operational mode.


I2C Pull-Up Jumpers

I2C Jumpers_5

Address Bits

The configuration is set by encoding a number into the 4 config bits on the bottom of the board. Close a jumper to indicate a 1 or leave it open to indicate a 0.


Use this table to see what the user port, address, and expansion port will become in each configuration:


Bold text is the default setting for the Qwiic Motor Driver

Thermal Conduction Area

The Qwiic Motor Driver is designed to operate small robot drive motors without a heatsink; we were able to run up to about 1.1A continuous current without going above 100°C. If you find that you need a heatsink, you can use our Theragrip Thermal Tape to attach three Small Heat Sinks across the thermal conduction area on the back of the board.


If you need more information on how to determine whether or not you need a heat sink, kick on over to the Serial Controlled Motor Driver Hookup Guide and scroll down to Typical Application Motors and Heat Sinking.


Small Heatsinks on the back of the Qwiic Motor Driver

Board Dimensions

All measurements are in inches. The Qwiic Motor Driver PCB measures 1x1 inch, with slight overhangs for the power and motor screw terminals.


Software Setup

Note: This code/library has been written and tested on Arduino IDE version 1.8.5. Otherwise, make sure you are using the latest stable version of the Arduino IDE on your desktop. If this is your first time using Arduino, please review our tutorial on installing the Arduino IDE. If you have not previously installed an Arduino library, please check out our installation guide.

Installing Arduino

If you haven't used the Arduino IDE before, head on over to our Installing the Arduino IDE tutorial to get set up:


Installing Arduino IDE

A step-by-step guide to installing and testing the Arduino software on Windows, Mac, and Linux.

Getting the Arduino Library

The Qwiic Motor Driver uses the same Arduino Library as the Serial Controlled Motor Driver (hereafter referred to as SCMD). To get the Arduino library, either download and install it from Github or use the Arduino Library Manager.

Download the Github repository

Visit the GitHub repository to download the most recent version of the library, or click the link below:


Use the library manager or install in the Arduino IDE

In the Library Manager, search for Serial Controlled Motor Driver. For help installing the library, check out our How To Install An Arduino Library tutorial.


Installing an Arduino Library

How do I install a custom Arduino library? It's easy! This tutorial will go over how to install an Arduino library using the Arduino Library Manager.

For libraries not linked with the Arduino IDE, we will also go over manually installing an Arduino library.

Experiment 1: Testing the Motors

Let's start by hooking up some motors and making sure they're running. Since the Qwiic Motor Driver uses the same PSOC as the Serial Controlled Motor Driver, the same examples will work with minor modifications.

Note: In lieu of using the external LiPo battery, it is also possible to use the 5V and GND pins from the RedBoard Qwiic.

Hardware Hookup


Testing the Motors

The following test is essentially the TwoMotorRobot.ino example from the SCMD library, but with a few minor changes to account for the defaults of the Qwiic Motor Driver.

Copy and paste the following code into your Arduino browser and upload.

Copy Code
//This example drives a robot in left and right arcs, driving in an overall wiggly course.
// It demonstrates the variable control abilities. When used with a RedBot chassis,
// each turn is about 90 degrees per drive.
// Pin 8 can be grounded to disable motor movement, for debugging.

#include <Arduino.h>
#include <stdint.h>
#include "SCMD.h"
#include "SCMD_config.h" //Contains #defines for common SCMD register names and values
#include "Wire.h"

SCMD myMotorDriver; //This creates the main object of one motor driver and connected slaves.

void setup()
pinMode(8, INPUT_PULLUP); //Use to halt motor movement (ground)

Serial.println("Starting sketch.");

//***** Configure the Motor Driver's Settings *****//
// .commInter face is I2C_MODE
myMotorDriver.settings.commInterface = I2C_MODE;

// set address if I2C configuration selected with the config jumpers
myMotorDriver.settings.I2CAddress = 0x5D; //config pattern is "1000" (default) on board for address 0x5D

// set chip select if SPI selected with the config jumpers
myMotorDriver.settings.chipSelectPin = 10;

//*****initialize the driver get wait for idle*****//
while ( myMotorDriver.begin() != 0xA9 ) //Wait until a valid ID word is returned
Serial.println( "ID mismatch, trying again" );
Serial.println( "ID matches 0xA9" );

// Check to make sure the driver is done looking for slaves before beginning
Serial.print("Waiting for enumeration...");
while ( myMotorDriver.ready() == false );

//*****Set application settings and enable driver*****//

//Uncomment code for motor 0 inversion
//while( myMotorDriver.busy() );
//myMotorDriver.inversionMode(0, 1); //invert motor 0

//Uncomment code for motor 1 inversion
while ( myMotorDriver.busy() ); //Waits until the SCMD is available.
myMotorDriver.inversionMode(1, 1); //invert motor 1

while ( myMotorDriver.busy() );
myMotorDriver.enable(); //Enables the output driver hardware


#define LEFT_MOTOR 0
#define RIGHT_MOTOR 1
void loop()
//pass setDrive() a motor number, direction as 0(call 0 forward) or 1, and level from 0 to 255
myMotorDriver.setDrive( LEFT_MOTOR, 0, 0); //Stop motor
myMotorDriver.setDrive( RIGHT_MOTOR, 0, 0); //Stop motor
while (digitalRead(8) == 0); //Hold if jumper is placed between pin 8 and ground

//***** Operate the Motor Driver *****//
// This walks through all 34 motor positions driving them forward and back.
// It uses .setDrive( motorNum, direction, level ) to drive the motors.

//Smoothly move one motor up to speed and back (drive level 0 to 255)
for (int i = 0; i < 256; i++)
myMotorDriver.setDrive( LEFT_MOTOR, 0, i);
myMotorDriver.setDrive( RIGHT_MOTOR, 0, 20 + (i / 2));
for (int i = 255; i >= 0; i--)
myMotorDriver.setDrive( LEFT_MOTOR, 0, i);
myMotorDriver.setDrive( RIGHT_MOTOR, 0, 20 + (i / 2));
//Smoothly move the other motor up to speed and back
for (int i = 0; i < 256; i++)
myMotorDriver.setDrive( LEFT_MOTOR, 0, 20 + (i / 2));
myMotorDriver.setDrive( RIGHT_MOTOR, 0, i);
for (int i = 255; i >= 0; i--)
myMotorDriver.setDrive( LEFT_MOTOR, 0, 20 + (i / 2));
myMotorDriver.setDrive( RIGHT_MOTOR, 0, i);

What You Should See

The code goes through and establishes communication with the motor driver and then runs each motor in arcs, resulting in a "wiggly pattern".

Things to note:

  • Serial.begin is periodically run until the returned ID word is valid.
  • Setup waits for isReady() to become true before going on to the drive section.
  • One motor is inverted by command at setup. Do it here so you don't have to mess with it later.
  • enable() is called to connect the drivers to the PWM generators.
  • LEFT_MOTOR and RIGHT_MOTOR are defined to ease use of the setDrive( ... ) function.

See the Arduino Library Reference section of the Serial Controlled Motor Driver Hookup Guide for more information on the functions defined in the Arduino library.

Experiment 2: Interactive Commands with UART

This example demonstrates the basic commands, plus some direct register access possible with only a UART available. This type of program could be easily run from a script from a more classic PC where I2C isn't available.

Interactive UART


  • Computer serial terminal set to 9600 baud
  • Terminal set to send CR and LF (Carriage return and line feed)
  • Config jumpers set to '0000', or all open
  • I2C PU jumper fully open
  • FTDI Basic or Serial Basic - either will work but ensure you have the 3.3V version


Make sure the Address Jumper 3 and I2C Pullup Jumpers are cut as you see here.

Connect the FTDI to the Qwiic Motor Driver as you see in the Fritzing diagram below. Attach two motors to the driver, one between A1 and A2, and the other between B1 and B2.


Example Commands

When you're ready, make sure you have the correct COM port selected in your Arduino IDE, open a Serial Monitor, and send the following commands:


This will read the ID register and return 0xA9


This will tell motor 0 to drive at half speed, forward -- But nothing will happen yet!


This will enable all drivers. Motor 0 should begin spinning at half speed.


This will tell motor 1 to drive at full speed in reverse. Now both should be spinning opposite directions.


D will disable both motors, which will stop spinning.

See the section UART Commands in the Serial Controlled Motor Driver Hookup Guide for a full command listing.


Need help?

If your product is not working as you expected or you need technical assistance or information, head on over to the SparkFun Technical Assistance page for some initial troubleshooting.

If you don't find what you need there, the SparkFun Forums are a great place to find and ask for help. If this is your first visit, you'll need to create a Forum Account to search product forums and post questions.

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