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BOOSTXL-BASSENSORS: DRV5055 testing and measurements

Other Parts Discussed in Thread: MSP430FR6989, DRV5055,


Currently I am working on a project using an MSP430FR6989 and BOOSTXL-BASSENSORS booster pack.  We are working on configuring the ADC to measure the DRV5055 hall sensor.  Right now, we are reading in a value of ~2 from the sensor, but it does not change with a magnet.  Is there a special sort of magnet to use to test this?  Right now I only have a fridge magnet.  Could this be an error in our ADC configuration?  Please let me know what you think, thanks!

  • Domenick,

    To rule out any issue with your ADC, I would first verify the outputs using an oscilloscope or volt meter.  You should be able to see the output change as the magnetic flux density changes.  DRV5055 is bi-polar, meaning that it should be able to detect either north or south poles.  The polarity of the field the sensor experiences will impact whether you see the output shift higher or lower.  

    What is important to remember here, is that with the Hall Effect, the sensor is only capable of detecting the portion of the B-Field Vector which is directed as shown in the diagram below.  Specifically, a vector directed from the bottom to top for a positive field (SOT-23).

    A fridge magnet is not a particularly strong magnet material.  I would expect you would need to get the magnet quite close to the sensor.  Magnet geometry, polarization, and alignment will all affect how much magnetic flux the sensor element is exposed to, and will impact your result.

    If you can find a stronger magnet it might help you prove the system is working before you tune the system to the fridge magnet you are working with.



  • Hi Scott,

    I believe we have our issue sorted.  We were enabling the DRV5055 D_V+ pin on the booster pack, when that should actually be set to 0 to power the DRV5055.  No issues with the hall sensor or magnet. Thanks!