Pololu corporation M2h24v14 User manual

Pololu Motoron Motor

Controller User’s Guide

1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.1. Available versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2. Contacting Pololu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3. Getting started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.1. Choosing the power supply and motor . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.2. Connecting everything . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.3. Enabling I²C on the Raspberry Pi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.4. Setting I²C addresses with a Raspberry Pi . . . . . . . . . . . . . . . . . . . . . . . . 17

3.5. Setting I²C addresses with an Arduino . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.6. Writing code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4. Motoron M3S256 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

5. Motoron M3 256 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

6. LED feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

7. I²C interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

8. Variable reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

9. Command reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

10. Cyclic redundancy check (CRC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

11. Reset pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

https://www.pololu.com/docs/0J84/all Page 1 of 67

1. Overview

The Motoron motor controllers are a family of general-purpose modules designed to control brushed

DC motors. The Motoron receives commands via I²C, so only two I/O lines are needed regardless of

how many Motorons you connect. The Motoron modules are designed to plug into either a Raspberry

Pi or an Arduino, and multiple Motoron controllers can be stacked on top of each other, allowing

independent control of many motors.

Motoron M3S256 Triple Motor Controller Shield

for Arduino (Connectors Soldered).

The Motoron M3S256 Triple Motor Controller Shield for Arduino, shown above, can control three

motors and is designed to plug into an Arduino [https://www.pololu.com/product/2191] or compatible

board, such as the A-Star 32U4 Prime [https://www.pololu.com/category/165/a-star-32u4-prime]. The

Motoron M3S256 can operate from 4.5 V to 48 V and has reverse-voltage protection on motor power

supply (down to −40 V). Its maximum continuous output current per motor is 2.0 A and it can provide

a peak current of 6.4 A for less than 1 second.

1. Overview Page 2 of 67

Motoron M3H256 Triple Motor Controller for

Raspberry Pi (Connectors Soldered).

The Motoron M3H256 Triple Motor Controller for Raspberry Pi, shown above, can control three

motors and is designed to plug into a Raspberry Pi. The Motoron M3 256 can operate from 4.5 V

to 48 V and has reverse-voltage protection on motor power supply (down to −40 V). Its maximum

continuous output current per motor is 2.0 A and it can provide a peak current of 6.4 A for less than

1 second.

Features and specifications

• Logic voltage range: 2.8 V to 5.5 V

• Control interface: I²C

• I²C clock speed: up to 400 k z

• Optional cyclic redundancy checking (CRC)

• Configurable motion parameters:

◦ Max acceleration/deceleration forward/reverse

◦ Starting speed forward/reverse

◦ Direction change delay forward/reverse

• PWM frequency: eight options available from 1 k z to 80 k z

• Command timeout feature stops motors if the Arduino stops functioning

• Configurable automatic error response

• Motor power supply (VIN) voltage measurement

• Optional pins make it easy to power the Arduino or Raspberry Pi from reverse-protected

1. Overview Page 3 of 67

motor power, either directly or through an external regulator [https://www.pololu.com/category/

136/voltage-regulators] (not included)

• Two status LEDs

• Motor direction indicator LEDs

•Motoron Arduino library [https://github.com/pololu/motoron-arduino] simplifies getting started

with an Arduino or compatible controller

•Motoron Python library [https://github.com/pololu/motoron-rpi] simplifies getting started with a

Raspberry Pi

1.1. Available versions

The Motoron family consists of two different controllers: the Motoron M3S256 (an shield for Arduino)

and the Motoron M3H256 (for the Rasbperry Pi).

Multiple versions of each controller are available to provide different options for the through-hole

connectors:

•Motoron M3S256 with soldered stackable headers and terminal blocks

[https://www.pololu.com/product/5030]

•Motoron M3S256 with headers and terminal blocks included but not soldered in

[https://www.pololu.com/product/5031]

•Motoron M3S256 without any headers or terminal blocks included [https://www.pololu.com/

product/5032]

•Motoron M3H256 with soldered stackable headers, soldered terminal blocks, and

standoffs [https://www.pololu.com/product/5033]

•Motoron M3H256 with headers, terminal blocks, and standoffs included but not

soldered in [https://www.pololu.com/product/5034]

•Motoron M3H256 without any standoffs, headers, or terminal blocks included

[https://www.pololu.com/product/5035]

See below for more information about these three options.

M3S256 with connectors soldered

1. Overview Page 4 of 67

Motoron M3S256 Triple Motor Controller Shield for Arduino

(Connectors Soldered).

The M3S256 version with connectors soldered [https://www.pololu.com/product/5030] has stackable

female headers and terminal blocks installed. This version allows you to use all the main features of

the board without additional soldering, as the motor and power leads can be connected to the board

via terminal blocks and the logic connections are made by simply plugging the shield into an Arduino.

M3S256 kit version

1. Overview Page 5 of 67

Motoron M3S256 Triple Motor Controller Shield Kit for Arduino.

The M3S256 kit version [https://www.pololu.com/product/5031] comes with the following connectors

included but not soldered, allowing for more installation options:

• One 1×10 stackable female header

• One 1×8 stackable female header

• Four 2-pin 3.5mm terminal blocks [https://www.pololu.com/product/2444]

• Four 2-pin 5mm screw terminal blocks [https://www.pololu.com/product/2440]

• One 1×25 male header [https://www.pololu.com/product/965]

There are more parts included than can be soldered to the board, providing different assembly options

to suit a variety of applications. Additional connector [https://www.pololu.com/category/19/connectors]

options are available separately, and wires can also be soldered directly to the board for more compact

installations.

1. Overview Page 6 of 67

Note: For applications where the Motoron M3S256 will be used as a standalone board or at

the top of a shield stack, it can be assembled with the included 0.1″ male header pins and

larger (5.0mm-pitch) blue terminal blocks. For applications where the Motoron will be one

of the intermediate members of a stack of shields, we recommend assembling it with the

stackable headers and smaller (3.5mm-pitch) green terminal blocks (just like our version

with connectors already soldered [https://www.pololu.com/product/5030]). The terminal blocks

are intended to be soldered to the larger through-holes for the power and motor connections,

and the blue ones should get locked together prior to installation (see our short video on

terminal block installation [https://www.youtube.com/watch?v=6pDyTLRZ2Eg]).

M3S256 with no connectors

Motoron M3S256 Triple Motor Controller Shield for Arduino (No

Connectors).

The "no connectors" version [https://www.pololu.com/product/5032] is just the PCB assembled with all of

the surface-mount components. This version is intended for those who want to solder wires directly to

the board or use a custom set of connectors [https://www.pololu.com/category/19/connectors].

M3H256 with connectors soldered

1. Overview Page 7 of 67

Motoron M3H256 Triple Motor Controller for Raspberry Pi

(Connectors Soldered).

The M3H256 version with connectors soldered [https://www.pololu.com/product/5033] has stackable

female headers and terminal blocks installed, and it comes with two standoffs [https://www.pololu.com/

product/1952], two screws [https://www.pololu.com/product/1968], and two hex nuts [https://www.pololu.com/

product/1967]. This version allows you to use all the main features of the board without additional

soldering, as the motor and power leads can be connected to the board via terminal blocks and the

logic connections are made by simply plugging the shield into a Raspberry Pi.

M3H256 kit version

1. Overview Page 8 of 67

Motoron M3H256 Triple Motor Controller Kit for Raspberry Pi.

The M3H256 kit version [https://www.pololu.com/product/5034] comes with the following connectors

included but not soldered, allowing for more installation options:

• Two 1×10 stackable female headers (or one 2×10 header)

• Four 2-pin 3.5mm terminal blocks [https://www.pololu.com/product/2444]

• Four 2-pin 5mm screw terminal blocks [https://www.pololu.com/product/2440]

• One 1×25 male header [https://www.pololu.com/product/965]

• Two standoffs [https://www.pololu.com/product/1952]

• Two screws [https://www.pololu.com/product/1968]

• Two hex nuts [https://www.pololu.com/product/1967]

There are more parts included than can be soldered to the board, providing different assembly options

to suit a variety of applications. Additional connector [https://www.pololu.com/category/19/connectors]

options are available separately, and wires can also be soldered directly to the board for more compact

installations.

1. Overview Page 9 of 67

Note: For applications where the Motoron M3 256 will be used as a standalone board or at

the top of a stack of boards, it can be assembled with the larger (5.0mm-pitch) blue terminal

blocks. For applications where the Motoron will be one of the intermediate members of a

stack of boards, we recommend assembling it with the smaller (3.5mm-pitch) green terminal

blocks (just like our version with connectors already soldered [https://www.pololu.com/

product/5033]). The terminal blocks are intended to be soldered to the larger through-holes

for the power and motor connections, and the blue ones should get locked together prior

to installation (see our short video on terminal block installation [https://www.youtube.com/

watch?v=6pDyTLRZ2Eg]).

M3H256 with no connectors

Motoron M3H256 Triple Motor Controller for Raspberry Pi (No

Connectors or Standoffs).

The "no connectors" version [https://www.pololu.com/product/5035] is just the PCB assembled with all of

the surface-mount components. This version is intended for those who want to solder wires directly to

the board or use a custom set of connectors [https://www.pololu.com/category/19/connectors].

1. Overview Page 10 of 67

2. Contacting Pololu

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

the Motoron. If you need technical support or have any feedback you would like to share, you can

pololu-motor-controllers-drivers-and-motors]. 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 11 of 67

3. Getting started

3.1. Choosing the power supply and motor

The information in this section can help you select a power supply [https://www.pololu.com/category/84/

regulators-and-power-supplies] and motor [https://www.pololu.com/category/22/motors-and-gearboxes] that will

work with the Motoron.

The Motoron is designed to work with brushed DC motors. These motors have two terminals such

that when a DC voltage is applied to the terminals, the motor spins.

When selecting the components of your system, you will need to consider the voltage and current

ratings of each component:

• 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.

• The operating voltage range of a Motoron is the range of voltages that can be supplied

to the Motoron’s VIN and GND pins, which power the motors. The operating voltage range

of the Motoron M3S256 and M3 256 is 4.5 V to 48 V. The Motoron requires a DC power

supply.

• The continuous current per motor of a Motoron is the maximum amount of current that

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

the Motoron M3S256 and M3 256 is 2.0 A.

• The rated voltage of a DC motor is the voltage at which the DC motor was designed to run.

You can apply voltages to the motor that are higher or lower than its rated voltage, but higher

voltages bring a risk of overheating the motor or reducing its lifetime.

• The no-load current of a DC motor is the current that the motor will draw if you apply the

rated voltage to the motor while its output is not connected to anything.

• The stall current of a DC motor is the current that the motor will draw if you apply the rated

voltage to the motor while forcing its output shaft to remain stationary.

There are guidelines you should be aware of when selecting the components of your system:

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

3. Getting started Page 12 of 67

voltage of each DC motor. Otherwise, you will not get the full performance that the motor was

designed for. If your power supply’s voltage is much higher than the rated voltage of a DC

motor, you might account for that by using lower speeds for that motor in your commands to

the Motoron.

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

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

damaged.

3. The typical current draw you expect for each motor should be less than the Motoron’s

continuous current per motor. Each motor’s typical current draw will depend on your power

supply voltage, the speeds you command the motor to move, and the current ratings of

the motor. If a motor draws too much current for too long, there is a risk of triggering the

Motoron’s overcurrent or overtemperature faults, which shut down the motor.

4. The current limit of the power supply should be higher than the typical total current draw for

all the motors in your system. Furthermore, it is generally good for the current limit to be much

higher than that so your system can smoothly handle the times where the motors are drawing

more than the typical current, for example when they are accelerating or encountering extra

resistance.

3.2. Connecting everything

This section explains how to connect motor power, motors, and a microcontroller to a Motoron motor

controller.

Connecting terminal blocks

We generally recommend using green 3.5mm-pitch terminal blocks [https://www.pololu.com/product/

2444] for the motor power and motor connections. If you have an assembled version of the Motoron,

these terminal blocks come soldered to the board. Otherwise, you will need to solder them yourself.

They should be soldered to the larger through holes for board power and motor outputs (GND, VIN,

M1A, M1B, M2A, …).

Alternatively, if you are not going to stack multiple Motorons on top of each other, you can use blue

5mm-pitch terminal blocks [https://www.pololu.com/product/2440], which are included in the kit versions.

The 5mm-pitch terminal blocks are tall enough that it is easy to accidentally cause a short between

the motor outputs of two Motorons that are plugged into each other. If you decide to use the 5mm

terminal blocks, we recommend using the tabs on the side of the terminal blocks to connect them

together before soldering them to the Motoron (see our video about how to install terminal blocks

[https://www.youtube.com/watch?v=6pDyTLRZ2Eg] for more information).

Connecting motor power and motors

3. Getting started Page 13 of 67

Motor power and motor connections for a Motoron M3S256 or M3H256 Triple Motor

Controller.

The negative terminal of the motor power supply should be connected to the Motoron’s large GND pin

or the smaller pins next to it. The positive terminal of the motor power supply should be connected

to the Motoron’s large VIN pin or the smaller pins next to it. These GND and VIN connections are

required for each Motoron in a stack of Motorons. Connecting two Motorons via stackable headers

does not connect their VIN pins at all, and it does not the connect their GND pins in a way that is

meant to carry the large currents involved in motor control. Note that connecting power to VIN does

not power the Motoron’s microcontroller and does not cause any LEDs to turn on.

Each motor should have one lead connected to an MxA pin (M1A, M2A, or M3A) and the other

lead connected to the MxB pin with the matching motor number. The Motoron’s concept of “forward”

corresponds to MxA driving high while MxB drives low, so you might consider this when deciding which

motor lead connects to which Motoron pin. You can also flip the wires later if you want to flip the

direction of motion.

3. Getting started Page 14 of 67

Connecting a controller

Motoron M3S256 shield being

controlled by an Arduino Uno.

A Motoron M3H256 being controlled by

a Raspberry Pi.

The Motoron M3S256 shield is designed to be plugged into the 1×10 and 1×8 female headers of an

Arduino or Arduino-compatible board that has the shape of the Arduino Uno R3 [https://www.pololu.com/

product/2191] using stackable female headers or male headers soldered to the Motoron. Similarly, the

Motoron M3 256 is designed to be plugged into pins 1 through 20 of a Raspberry Pi using female

headers.

Plugging the Motoron into a controller this way connects the GND, SDA, and SCL pins of both

boards, allowing the controller to communicate with the Motoron via I²C. It also powers the Motoron’s

microcontroller by connecting the Arduino’s IOREF or the Raspberry Pi’s 3V3 pin to the Motoron’s

logic voltage.

The Motoron does not need to be connected directly to the controller: it can be connected through

another board (including other Motoron boards) as long as those boards pass the GND, SCL, SDA,

and logic voltage connections through.

You can also connect the Motoron to a controller board that has a different shape as long as you

make the same connections. The Motoron’s GND, SCL, and SDA pins should be connected to the

corresponding pins on the controller board, and the Motoron’s logic voltage (labeled IOREF or 3V3

depending on which type of Motoron you have) should be connected to the logic voltage supply of the

controller board, which should be between 2.8 V and 5.5 V.

Most of the pins on the Motoron have a spacing of 0.1" and are on the same 0.1" grid, making it easy

to connect the Motoron to a perf-board or breadboard.

3. Getting started Page 15 of 67

A Raspberry Pi Pico on a breadboard

using a Motoron M3S256 shield to

control three motors.

An Arduino Micro on a breadboard

using a Motoron M3H256 to control

three motors.

After you have connected one Motoron to a microcontroller, you can connect other Motorons to the

same microcontroller simply by stacking them above or below the first one.

Once you make the GND and logic power connections and turn on the logic power, you should see

the Motoron’s yellow LED blink. The red LED will also turn on unless something is communicating with

the Motoron and causing it to turn the LED off.

Powering the controller

By default, the Motoron does not supply power to the Arduino or Raspberry Pi, so you will need to

power them separately. owever, there are options for powering the controllers, as documented in

Section 4 for the M3S256, and in Section 5 for the M3 256.

3.3. Enabling I²C on the Raspberry Pi

This section explains how to enable the correct I²C bus on your Raspberry Pi, make sure that your

user has permission to access it, and test your setup.

The Motoron is designed to connect to the I2C1 bus on the Raspberry Pi, which uses GPIO pin 2 for

SDA and GPIO pin 3 for SCL. If you are using Raspberry Pi OS, this bus is represented by /dev/

i2c-1 : that is the name of the device node that programs on your Raspberry Pi will open in order to

communicate with the Motoron or any other targets on the bus.

Try typing ls /dev/i2c* to list your system’s available I²C busses. If /dev/i2c-1 is not in the list then

you should run sudo raspi-config nonint do_i2c 0 to enable it. You must reboot your Raspberry Pi

for this change to take effect.

We recommend adding your user to the i2c group so you can access the Motoron and other I²C

devices without using sudo . Run the groups command to see what groups your user belongs to.

3. Getting started Page 16 of 67

If i2c is not in the list, then you should add your user to it by running sudo usermod -a -G i2c

$(whoami) , logging out, and then logging in again.

After you have enabled I²C and connected your Motoron to your Raspberry Pi’s I²C bus, run i2cdetect

-y 1 . If everything is set up correctly, you should see output like this:

0 1 2 3 4 5 6 7 8 9 a b c d e f

00: -- -- -- -- -- -- -- --

10: 10 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

70: -- -- -- -- -- -- -- --

This output means that the Raspberry Pi detected a device at address 16 (0x10 in hex), which is the

default I²C address used by the Motoron.

3.4. Setting I²C addresses with a Raspberry Pi

Each device on an I²C bus should have a unique address so that you can communicate with the device

without interfering with other devices on the bus. By default, the Motoron uses I²C address 16, so if

you have connected two or more Motorons to your bus, or you have another device that uses address

16, you will need to change the I²C addresses of one or more Motorons.

Warning: If you have devices on your I²C bus that are not Motorons, the procedure below

could cause undesired behavior when it sends commands to them that are intended for the

Motorons.

The recommended procedure for setting the I²C address of one or more Motorons that are connected

to the I²C bus of your Raspberry Pi is:

1. Ensure that the JMP1 pin on each Motoron is not connected to anything.

2. Download the Motoron Motor Controller Python library for Raspberry Pi [https://github.com/

pololu/motoron-rpi], and install its dependencies, as described in the “Getting started” section

of its README file.

3. In a Terminal, use cd to navigate into the directory holding the library and its examples.

4. Run ./set_i2c_addresses_example.py . This utility will print some information and then

prompt you for a command.

5. Perform a scan of the I²C bus by typing “s” followed by “Enter”. You should get output that

looks like this:

3. Getting started Page 17 of 67

Scanning for I2C devices…

Found device at address 0

Found device at address 16

Done.

The scan detects that a device on the bus is responding to address 16 because that is

the Motoron’s default address. It also detects a device on address 0 because that is the

I²C general call address and all Motorons respond to it by default, in addition to the normal

address. We will use address 0 to send commands in later steps, so if the scan does not

detect any devices on address 0, those steps will probably fail.

6. Connect the JMP1 pin of one Motoron to GND. If you have not soldered headers to the

JMP1 pin and its adjacent GND pin, you can connect those two pins together using a wire,

test clip, or with a shorting block [https://www.pololu.com/product/968] attached to a 1×2 male

header [https://www.pololu.com/product/965]. Connecting JMP1 to GND is how we select which

Motoron’s address will be changed in the next step. Only one Motoron at a time should have

its JMP1 pin connected to GND.

7. Set the address of the selected Motoron by typing “a”, followed by the address (in decimal),

and then “Enter”. We recommend picking an address between 8 and 119 that is not in use

by any other devices on your bus (numbers outside that range could work too, but they are

reserved for other uses by the I²C specification). For example, type “a17” to set the address

of the Motoron to 17. Alternatively, you can just send “a” by itself in order to have the program

automatically pick an address for you, starting at 17 and skipping addresses that are already

in use on the bus.

This sends a “Write EEPROM” command to all of the Motorons using address 0, but the

command will only have an effect on the one Motoron whose JMP1 line is low. That Motoron

will record the address in its non-volatile EEPROM memory, but will not start using it yet.

8. Disconnect the JMP1 pin from GND.

9. Repeat the last three steps for every Motoron whose address you wish to change.

10. Type “r” to make the new addresses take effect. This sends a “Reset” command to all of the

Motorons using address 0. Alternatively, you can power cycle the system or use the RST pin

to reset the Motorons.

11. Perform another scan of the I²C bus by typing “s”. Check that a device is now found on each

of the addresses that you assigned.

3.5. Setting I²C addresses with an Arduino

Each device on an I²C bus should have a unique address so that you can communicate with the device

without interfering with other devices on the bus. By default, the Motoron uses I²C address 16, so if

you have connected two or more Motorons to your bus, or you have another device that uses address

3. Getting started Page 18 of 67

16, you will need to change the I²C addresses of one or more Motorons.

Warning: If you have devices on your I²C bus that are not Motorons, the procedure below

could cause undesired behavior when it sends commands to them that are intended for the

Motorons.

The recommended procedure for setting the I²C address of one or more Motorons that are connected

to the I²C bus of your Arduino is:

1. Ensure that the JMP1 pin on each Motoron is not connected to anything.

2. Install the Motoron Arduino library [https://github.com/pololu/motoron-arduino] using the Arduino

library manager. You can open the Library Manager from the “Tools” menu by selecting

“Manage Libraries…”. If necessary, see the library’s README [https://github.com/pololu/

motoron-arduino] for more information about how to install it.

3. Upload the SetI2CAddresses example to your Arduino. If the Motoron library is installed

properly, you can find this example under Files > Examples > Motoron > SetI2CAddresses.

4. Open the Arduino IDE’s Serial Monitor, which you can find in the “Tools” menu.

5. Perform a scan of the I²C bus by typing “s” in the box at the top of the Serial Monitor and

clicking “Send”. You should get output that looks something like this: