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DRV8434PEVM: Turning motor problem

Carmelo Zarbo
Prodigy 10 points
Part Number: DRV8434PEVM
Other Parts Discussed in Thread: MSP-FET, DRV8434, DRV8434E

I bought the DRV8434PEVM evaluation board... I would like to use the the driver with STEP/DIR so on the evaluation board I removed the R6 for the interface. I use the software DRV84xx 0.1.4 and MSP-FET programming tool I program the firmware version Step/DIR (DRV84xx). When I set the microstep and other parameter I feel like the motot moves but doen't turns. Where is my mistake? Thank you very much

  • 0
    TI__Guru 55615 points

    Carmelo,

    This will not work.  The device itself on the board does not support STEP/DIR.  You will need the following EVM with STEP/DIR device on board.

    https://www.ti.com/tool/DRV8434EVM

    Regards,

    Ryan

  • 0 in reply to Ryan Kehr
    Prodigy 10 points

    So i have another question....The chip DRV8434 can work in different way (STEP/DIR, PWM) but for the evaluation board doesn't work?

    so when i order the component i will have to specify which one i need? I don't see different part numbers based on the way it works. it is specified in the pin interface

    I have another doubt. is it possible to specify the holding current of the motor? When I stop the motor I need to keep the position. 

    Thank you very much.

  • +1 in reply to Carmelo Zarbo
    TI__Guru 55615 points

    Hello!

    If you check closely, you will find different orderable part numbers. 

    DRV8434 is STEP/DIR

    DRV8434P is PWM

    DRV8434E is Phase/Enable

    It sounds like you just want the DRV8434 (no "P" or "E" at the end) for STEP/DIR interface.

    Holding current is specified by the VREF pin.  When you stop issuing steps, current in windings will stop at current levels as defined by the STEP table in the datasheet.  100% current STEP is defined by VREF.  You can find formula in the datasheet.  The table shows the fractional current based on this.

    Regards,

    Ryan

  • 0 in reply to Ryan Kehr
    Prodigy 10 points

    Hello, thank you very much for your reply. Now it's more clear for me. Since you are an expert  I would like to ask you which one is the best for my application. I need a device for control a stepper motor for precise positioning and very smooth in turning. It's clear for me that I need an external counter for the positioning. Right? My choice was STEP/DIR... With micro controller I will provide the STEP using 1/256 microsteps... 

    Thank you very much.

    Regards,

    Carmelo Zarbo

  • 0 in reply to Carmelo Zarbo
    TI__Guru 55615 points

    Carmelo,

    I recommend STEP/DIR device.  If you need precise positioning, then you will need an EXTERNAL encoder to close the loop on position.

    Regards,

    Ryan