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DRV8889-Q1: Are there any pinout that I can use it to detect the motor current by ADC from MCU?

John Ding
Prodigy 90 points
Part Number: DRV8889-Q1

I am investigating the stepper motor driver DRV8889-Q1.

Stall detection, 1/256 micro-stepping, STEP/DIR, smart tune are the features we need.

But we also want to detect the motor current using ADC from MCU.

Question: Are there any pinout from DRV8889-Q1 that I can use it to detect the motor current by ADC from MCU?

Thanks and best regards,

John Ding

  • 0
    TI__Guru 55615 points

    John,

    Thank you for the post.  Unfortunately, there is no way to monitor the current on this device through any pin.

    Out of curiosity, why do you need this capability?   With the STEP/DIR control, we internally regulate the current to the proper micro-stepping levels and close the loop internally to the device.  

    It could help us improve future parts if I can better understand the use case here and why you need the current information external to the device.

  • 0 in reply to Ryan Kehr
    Prodigy 90 points

    Ryan,

    Thanks a lot for your quick response. 

    We need the motor current to monitor the friction torque added to motor while motor is moving. Then we can evaluate our system whether it is smooth enough.

    For example:

    Motor needs to take one platform moving along the lead screw. There is friction torque distributed along the lead screw.

    At some positions of the lead screw, the current of motor will shoot up if the friction torque between leadscrew and platform gets higher.

    Question:

    Do we have one motor driver chip capable of STEP/DIR, smart tune, 1/256 micro step, stall detection, and current monitoring?

    Thanks a lot and best regards,

    John Ding

  • 0 in reply to John Ding
    TI__Guru 55615 points

    John,

    The answer to your question for now is that we do not have such a motor driver.

    But, could you try monitoring the torque_count value via SPI?  This should be proportional to any change in load.  You can disable stall detect in the device and just monitor this value with SPI to determine if friction torque is increasing.  

  • 0 in reply to Ryan Kehr
    Prodigy 90 points

    Ryan,

    Thanks a lot for all your help. After carefully investigate the documents, torque_count read from SPI should be able to meet our need.

    We may get the demo board to have a try.

    Thanks a lot

    John Ding

  • 0 in reply to John Ding
    TI__Guru 55615 points

    John,

    Excellent!  Please do and thank you for your post.