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DRV8256PEVM: Design questions for IO pins

SouthernAtHeart
Prodigy 60 points
Part Number: DRV8256PEVM

Hi, I'm designing a motor driver board around the DRV8256PPWPR IC. It will be controlled by an Atmega328P-AU microprocessor, with a 5 volt supply.

A few questions regarding the various pinouts.

1) INT1 & INT2 will be connected to 2 digital pins on the MCU. Do I need something like a 1K resistor in series with the MCU digital pins and the INT1 & INT2 pins?  Or can I connect the INT1/2 pins directly to the digital pins?

2) I will not be using the Sleep function, so I would pull-up the nSLEEP pin to my 5 volt supply through a 10K resistor?

3) I will not be using the uFault diagnostics from the motor driver, So I can just tie the uFault pin to a 10K pull-up resistor on it to my 5 volt rail?

Thanks,

ck

  • +1
    TI__Mastermind 37683 points

    Hi Charlie,

    SouthernAtHeart said:
    1) INT1 & INT2 will be connected to 2 digital pins on the MCU. Do I need something like a 1K resistor in series with the MCU digital pins and the INT1 & INT2 pins?  Or can I connect the INT1/2 pins directly to the digital pins?

    The IN1 and IN2 pins can handle up to 5.75V so it is okay to connect to 5V MCU.

    SouthernAtHeart said:
    2) I will not be using the Sleep function, so I would pull-up the nSLEEP pin to my 5 volt supply through a 10K resistor?

    You are correct.

    SouthernAtHeart said:
    3) I will not be using the uFault diagnostics from the motor driver, So I can just tie the uFault pin to a 10K pull-up resistor on it to my 5 volt rail?

    If you have no plans on monitoring the nFAULT, you can leave it unconnected. The 10k is required if you wish to monitor the nFAULT with an MCU or LED indicator. Although, we do recommend to have the pull up resistor for diagnostics purpose.

    Regards,

    Pablo Armet

  • 0 in reply to Pablo Armet
    Prodigy 60 points

    Thanks. I will use a 10K pull up on nFAULT, in case I need it for diagnostics purposes.  

    One more question:  VM supply for the high current will be 12 volt.  an onboard regulator will supply +5 volts for my mcu. When programming the mcu, I will have nSLEEP pulled up (10K) to my +5 volt supply rail, but the chip will not have the VM power supply. So during programming my mcu, nSLEEP will be pulled high to 5 volts, but there will not be power on the VM pins.  I assume this is not a problem?

    thanks.

  • +1 in reply to SouthernAtHeart
    TI__Mastermind 37683 points

    Charlie,

    You are correct. That should not be a problem.

    -Pablo