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DRV8428E: Micro step Mode selection with HiZ

VETRIVEL M1
Prodigy 70 points
Part Number: DRV8428E
Other Parts Discussed in Thread: DRV8428

Dear Team,

I need to use all the micro step selections using DRV8428.

in this driver the all stepping given in selection table. but some of them are HiZ mentioned.

How to give HiZ input to M1 mode pin selection. During run mode how to change the M1 pin mode as HiZ.

also 330K ohms GND connection need to give for another micro stepping. How this made possible with single MCU pin

  • 0
    TI__Mastermind 21166 points

    Hey Vetrivel,

    We use two GPIO/ on the MCU to implement all the microstepping. 

    We have one GPIO to switch in 330k to ground. and another one to either HiZ, 1 or 0.

    MSP 430 support HiZ on the GPIO.

    Please consult the EVM schematic (found in EVM hardware design files) for more information on how this is implemented..

    Best,

    Akshay

  • 0 in reply to Akshay Rajeev Menon
    Prodigy 70 points

    Dear Akshay,

    I already got this from EVM

    in all steps selection, what is the MCU pin status we don't know

    Can you help me with one table that suggest the status of MCU pins for All microstep.

    For HiZ how achieved with MCU pin. the table will help me to implement the steps faster.

  • 0 in reply to VETRIVEL M1
    TI__Guru 55595 points

    Hello,

    Table is in the datasheet:

    You will need 1 GPIO for MO and 2 GPIOs for M1 (one to switch 0, 1, HIZ and the other to switch in a 330kohm resistor to GND by setting that GPIO to "low" state).  

    I am not sure what MCU you are using, but many including our onboard MSP430 have this capability.  The firmware is available online if you would like to check for the HIZ configuration command.

    Regards,

    Ryan

  • 0 in reply to Ryan Kehr
    Prodigy 70 points

    Dear Ryan,

    this table is already in datasheet I know

    during running MCU pins how made it to HiZ we are not aware of that condition in pins. 0 or 1 we can make it. HiZ is new to me also it is in run condition of MCU program. So I requested that in order to make this HiZ status to M1 pin. what is the condition need to be maintained in MCU pins. that table I requested.

    Anyway I will check the firmware of EVM board and if any support needed I will come back to you

  • 0 in reply to VETRIVEL M1
    TI__Guru 55595 points

    Vetrivel,

    OK, I am sorry that I am not a MSP430 expert and unable to give good guidance on how to make GPIO pin HIZ.  I just know it is possible and we do it in the firmware, just not sure how to direct you.  

    Please let us know if you need more support on the motor driver.

    Regards,

    Ryan