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DRV8889-Q1: DRV8889-Q1

Lakshmi Teja Gedela
Prodigy 90 points
Part Number: DRV8889-Q1

Hi Team, 

I want to know about a outcome .
In CTRL-2 (control register), bit 7 is mapped with DIS_OUT field and it is also mentioned that it is ORed with DRV_OFF Pin. So is it like : 

1 - (Register - DIS_OUT = 0)  ||  (Pin -  DRV_OFF = 0) =  0.
2 - (Register - DIS_OUT = 1)  ||  (Pin -  DRV_OFF = 0) =  1.
3 - (Register - DIS_OUT = 0)  ||  (Pin -  DRV_OFF = 1) =  1.
4 - (Register - DIS_OUT = 1)  ||  (Pin -  DRV_OFF = 1) = 1.

So want to understand that my understanding is correct or it is ANDed instead of ORed. Please clarify on this point.


Thank you in advance .

  • +1
    TI__Guru 55605 points

    Hello!

    Thank you for your post.

    Your understanding is 100% correct.  

    Regards,

    Ryan

  • 0 in reply to Ryan Kehr
    Prodigy 90 points

    Hi Team,

    I have 2 more questions related to the DIR pin & reset

    1. I want to understand the scenario of DIR pin & control register3(DIR field)

          a. DIR pin=0

               ctrl reg-DIR=0 - clockwise

               ctrl reg-DIR=1 - counter clockwise

         b. DIR pin=1

               ctrl reg-DIR=0 - counter clockwise

               ctrl reg-DIR=1 -  clockwise

    could you please confirm is our above understanding is correct?

    2. Do we need to drive both DIR pin and ctrl reg3(DIR field) simultaneously or we can control direction by register value when DIR pin is Zero?

    3. In 8889 how can we achieve the reset functionality?

    please confirm us in your earlier convenience.

    Thanks.

  • +1 in reply to Lakshmi Teja Gedela
    TI__Guru 55605 points

    Hello again!

    There is another bit in the same register (CTRL3) that determines if the external hardware DIR pin is used or if the SPI controls the direction.

    For SPI control, set bit 5 to a "1".  For external hardware pin, DIR, set this bit to "0".  

    Clockwise vs. counter clockwise rotation will depend on how your motor is wired.  This you will have to determine thru experimentation in your system.

    Regards,

    Ryan

  • 0 in reply to Ryan Kehr
    Prodigy 90 points

    Thank you for the above response Ryan.

    Could you also please confirm In 8889 how can we achieve the reset functionality? 

    Thanks in advance.

  • 0 in reply to Lakshmi Teja Gedela
    TI__Guru 55605 points

    Please see section 7.4.4. nSLEEP Reset Pulse in the datasheet  It should be clear from that.

    Regards,

    Ryan