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DRV8834: DRV8834EVM

Part Number: DRV8834

Please help me with the DRV8834EVM RevB evaluation board.

GUI configuration: dual H-bridge.

Set-up: step motor (3.3VDC rated voltage, 2 phases, max. starting frequency of 800 PPS) connected to AOUT1&AOUT2, BOUT1&BOUT2.

Issue: period of PWM pulses is 32.4 uS. The step motor cannot rotate at this high frequency.

Question: How can I change period of PWM pulses ?

Thanks,

Michael Rivlin

  • Hi Michael,

    I have a couple questions:

    • Are you sure you are using dual h-bridge configuration?. It looks to me like you might be using internal micro-stepper Ctrl since you can choose the starting speed.
    • When you try running the motor, did the motor turn and then suddenly stop?
    • If the GUI configuration is indeed internal micro-stepper control, what is the starting speed, target speed, microstep rate, acceleration rate, and decay mode? 

  • Hi Pablo,

    1. Pls see below screnshoot of the GUI

    2. When I try running the motor, the motor doesn't response at all. See below screenshot of the AOUT1&AOUT2, BOUT1&BOUT2:

    i very appreciate your help.

    Michael

  • Hi Michael,

    Thank you for the information.

    I will need more time to understand why the motor is not running under the settings you are using. You should expect a response from me by 11/5 

  • Hi Michael,

    In order to use dual h-bridge control (phase/enable), you have to create the following sequences (drv8834 datasheet section 9.2.4.3) in order to drive a stepper motor:

    Using the GUI's dual H-bridge control mode, the values of phase A and Phase B  have to be manually change to move to the next step in the sequence, that is why the motor is not running under your GUI settings.  

    If you need to use phase/enable mode, I suggest you use the external microstepper control which uses the msp430 to vary Avref and Bvref to create up to 1/512 microstepping (similar to the microstepping sequence shown in figure 20 above).

  • Thank you very much Pablo!