Freescale Cup Motor Driver Board

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Freescale Cup Motor Driver Board

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Freescale Cup Motor Driver Board

For details on how to use the Motors, visit theDC Motor Tutorial


Boards before 2013Current Board



Rev. 0Rev. 1

Technical Details

Revision 1 (Schematics, design files, sample code, instructional videos)

Revision 0 (Schematics)

H-Bridge Specifications

Freescale MC33931 Datasheet

Pro Tips:

#1 - Electro-Magnetic Interfence (EMI)

This has been mitigated in the rev. 1 board.

In many cases the dc drive motors give off much EM interference causing poor data from the camera, and decreasing the servo motor performance substantially. In most cases around a PWM value of 20-25 duty cycle at the drive motors, caused detrimental problems. This problem was remedied in two ways, (1) connecting capacitors between the motor leads, the closer to the drive motor the better; (2) There is a way to connect the camera directly to the kwikstik and bypass the motor board.

#2 - Rev. 0 Board workaround to Enable Braking

This has been fixed in the rev. 1 board.

In order to go forward AND backwards, you have to have control over IN1 and IN2 (see table below).


If you look at the schematic, you can see that IN1 is directly connected to GND. In order to enable breaking you need to lift pin 43, solder a wire to it and control it properly.


General Tutorial on the DC Motor Control

Qorivva: DC Motor Tutorial

Kinetis Tower: DC Motor Tutorial

Design evolution of motor board

prior to 2010 - Freescale Cup Cars utilized the MC33932EVB
2010~2012 - Freescale Cup teams migrated to the current Interface/Motor board featuring Dual H-Bridges
[Not manufactured] Tower and Trak Compatible Interface/Motor Control Board (Design files if you want to make one!)

2013+ - FRDM-KL25Z shield

Labels (1)

Hey is there a schematic of the actual board with its pins and ports illustrated...

And I have a blue motor board what is the difference with the one that you own?

hi, you can refer the attachment for schematic. i also get the blue one. both are same

Hey Mohamad,

Thanks for the tip, the two boards are indeed the same [green and blue boards], the ports to the DC motors have different names for the boards but it still follows the picture posted in the tutorial. Also I was not sure what the jumper wire was used for, the one between the left motor pin and the right motor pin. Would you happen to know its purpose?

Thanks a lot!

the jumper wire is needed to close the connection for the left motor driver. if not, your left motor will not run. you can also put your right motor cable in to it and leave the right most port vacant so that both motor will be driven by your left motor driver only.  


As you said I am getting interference in camera readings at 20 % pwm of motors. Tried different ways like coiled wires, ferrite core and capacitors but non worked. can you suggest some other ways to remove this interference. Also what value of cap should we use??

Are you sure it is coming from the motors?  Try this trick to remove light noise


I need the car to go forward and backward and I'm a little reluctant when it comes to lifting pin 43 because I am afraid I will end up breaking it in time.

I was thinking to use one MC33931 to drive both motors forward and the other MC33931 to drive both motors backward, keeping one disabled when the other one is enabled in order to avoid short circuits.

What is your opinion on this approach?

Would it result in breaking the H-bridges?

Thank you!

That is an interesting idea.  If you were to absolutely make sure one H-Bridge was disabled while the other was enabled, yeah, I think you could do that.  If you drive them both (opposite direction) at same time though it probably won't end well.  ;-)

The pin 43 mod shouldn't intimidate.  A soldering iron and a sharp instrument is really pretty easy.  (And always reversible/fixable with enough patience)  Smoking H-Bridges because of overloads, not so fixable.

Hey John,

We actually broke one of our pins, but you said that they are easily fixable? I am not familiar with surface soldering...


If you physically broke the pin off the chip it's probably not fixable.  If you "broke" it by lifting the pin off the board, that is fixable.

Post a quality zoomed in picture, let's take a look at the damage.

Yeah, the pin actually came off the chip... I'll take a post quality picture though.



Thanks for answering so fast!

Have a nice day!


I just took the picture I hope you can see clearly, where there is a dent

that is the missing leg.

Thank you

On Feb 8, 2013 9:37 PM, "John McLellan" <>


Not seeing photo, did you email or put in post?

Here's the picture, my phone did not attach the picture last night... But it is completely off... A solution would be using another H-bridge, but it will require re- routing the current to the H- bridge, which is like designing a new motor board... I am not sure if that's a good idea after all but it would a great learning experience...


how can i buy (Rev. 1)motor driver??

Hello Cheng,  You can acquire the Motor Driver board at with the part number: TFC-Motor.

Have a nice day!

Version history
Revision #:
1 of 1
Last update:
‎07-12-2012 12:24 PM
Updated by: