Introduction

 

Element14 was kind enough to provide me with an Infineon DC Motor Control ShieldInfineon DC Motor Control Shield after the Internet of Holiday Lights RoadTest Plus, in which contestants were given another Infineon shield as part of the kit: the Infineon RGB LED ShieldInfineon RGB LED Shield.

 

This post will cover my first observations and tests using the DC Motor Shield. You can find my review and project using the RGB LED Shield here.

 

 

 

 

DC Motor Shield

Screen Shot 2015-02-07 at 20.24.27.png

 

The shield is built around two BTN8982TA: a high current half bridge for motor control applications.


The BTN8982TA package consists of:

  • a driver circuit
  • one p-channel highside MOSFET
  • one n-channel lowside MOSFET

 

Offering:

  • logic level inputs (driver circuit)
  • high PWM frequency control capabilities
  • various protections, such as: undervoltage, short circuit, overcurrent and overtemperature
  • diagnosis with current sense
  • adjustable slew rates (fixed on the shield though)

 

 

source: BTN8982TA datasheet                                             

 

 

First observations

 

Out of the package, the board looks very well made and of high quality. There are however a few things that immediately drew my attention:

  • no headers on the board or in the box
  • a huge vertically mounted capacitor
  • no (screw) terminals, but instead big ring shaped pads

IMG_5852.JPGIMG_5853.JPG

Top and bottom view of the shield

 

 

No headers

 

This was already the case with the RGB LED Shield. My main problem with this is that you cannot start using the shield right away. If you have anticipated for the missing headers, the only remaining task is to solder them on. Else, you're stuck with an unusable shield until you are able to find a fitting pair of headers, which would probably delay you a day or two.

 

The fact that no headers are soldered on does give you the option to choose your own header type though: stackable, long, short, ... Whatever type suits your needs.

 

My suggestion remains the same as last time: include a pair of tall stackable headers in the box, preferably even soldered on.

 

 

Huge capacitor

 

The huge capacitor in the middle of the board really sticks out: about 25mm! One of the advantages of the BTN8982TA, is that it has very low board space consumption for the features it offers. I personally feel the capacitor obsoletes that advantage completely. It also prevents other shields to be stacked on top of this one, which seems like a big problem as other shields with displays or prototyping areas require to be on top.

 

Couldn't the capacitor have been put on its side ?

 

 

No (screw) terminals

 

One of the things I liked very much about the RGB LED Shield, were the screw-less terminals for both the power supply and the RGB LED strip. I was expecting something similar for this shield, but instead found big ring shaped pads. This will require soldering as opposed to the terminals, which makes it less practical for testing different types of motors and power supplies.

 

Is there a specific reason (except cost), why pads would be better than (screw) terminals ?

 

 

Software

 

I was looking for some sample code to use the shield with an Arduino, but I couldn't find any!

 

Not on the Infineon or E14's pages on the shield:

 

Unfortunate, but not a disaster as the shield seems easy enough to control.

 

This is the test sketch I came up with for testing:

 

 

First tests

 

There are two tests I wanted to perform using the motors I had at hand:

  • half-bridge configuration: controlling two unidirectional DC motors
  • H-bridge configuration: controlling a single bidirectional DC motor

 

But first ... finding a set of suitable headers to be able to use the shield and make some practical modifications.

 

Headers

 

I've ordered tall stackable headers for Arduino, but it will take some days until they get here. In the mean time, I've been experimenting with what I had at hand.

 

The first tests was to use different size male headers with an Arduin UNO. Using the typical size male headers, there was contact between the shield's VBAT connector and the UNO's USB port, which would create a very nasty short circuit. With a different size male headers the problem was resolved for the UNO.

 

IMG_5857.JPGIMG_5861.JPG

Testing different size headers to avoid contact between shield and USB port on the UNO

 

The next test was about finding suitable headers for the YUN. The Arduino YUN has a vertically mounted USB port and an ethernet port, which are sure to cause problems as they are taller than the UNO's USB port. The tall headers working for the UNO were too short for the YUN and had to be combined with intermediate female headers.

 

IMG_5866.JPGIMG_5864.JPG

Finding an appropriate combination of headers for the YUN

 

I'll be posting an update as soon as I receive the tall stackable headers I've ordered. In the mean, this will have to do

 

UPDATE: Extra tall stacking headers have arrived! The clearance for the YUN is just enough, I did put some tape on the bottom of the shield to avoid direct contact. With the capacitor on its side, it is possible to plug in another shield on top of the motor shield, although it should have long headers.

 

photo 4.JPGphoto 2.JPG

Motor shield with extra tall stacking headers

 

Modifications

 

There are two modifications I made, based on the feedback given during my first observations: laying the capacitor on its side and using screw terminals.

 

photo 2.JPG

Screw terminals and capacitor on its side

 

Single bidirectional motor

 

To use a single bidirectional motor with the shield, following steps were taken:

  • connect the motor to OUT1 and OUT2
  • connect a power supply (I used 12V/2A)
  • set INH1 and INH2 to HIGH
  • use IN1 for direction 1, IN2 for direction 2

 

 

Two unidirectional motors

 

To use a two unidirectional motors with the shield, following steps were taken:

  • connect the motor 1 to OUT1 and GND, motor 2 to OUT2 and GND
  • connect a power supply (I used 12V/2A)
  • set INH1 and INH2 to HIGH
  • use IN1 to control motor 1, IN2 for motor 2

 

Demo

 

Here's a video of the different modes in action: