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MCF8329A: Communicating with MCF8329A through I2C

Prahaladh S
Intellectual 350 points

Part Number: MCF8329A

Hi,

Greetings...

We're using MKE17Z512VLH9 to drive MCF8329A to drive 57ZWX01 BLDC motor (24V, 8 poles, 3 phases).

We're communicating from MCU to MCF8329A through I2C with an address of 0x01. 

We're getting NACK when we probe the SCL & SDA pins. 

In MKE17Z512VLH9, the Vcc is given as 5V & the SCL & SDA lines are pulled up to 5V with 4.7k ohms.

We're giving 5V to VREG pin, getting 3.3V from AVDD & 1.5V from DVDD in MCF8329A.

Kindly let me know what could be the possible reasons for the NACK in the I2C.

Please guide us in this regard.

Warm Regards,

Prahaladh S

  • 0
    TI__Expert 7540 points

    Hi Prahaladh,

    Please confirm that the MCF8329A SPEED/WAKE pin is pulled high during I²C communication. Additionally, could you verify the logic levels of the SDA and SCL pin, are both of them remaining high?

    If the SPEED/WAKE pin is high and both SDA and SCL are high, please confirm whether this is your first attempt to communicate with the device.

    Thanks,

    Dhinesh

  • 0 in reply to Dhinesh
    Intellectual 350 points

    Hi Dhinesh,

    Thank you for your response.

    The WAKE pin is pulled high during I2C communication. We're getting pulses in SCL & SDA (max. is 5V.).

    This is the 1st time, we're communicating with the device.

    Kindly let us know what registers need to be updated with respect to the motor parameters.

    Warm Regards,

    Prahaladh S

  • 0 in reply to Prahaladh S
    Intellectual 350 points

    Hi Dhinesh,

    One more query. Is it possible to change the default I2C address of MCF8329A ? We have 3 such MCF8329A ICs in our board & are planning to communicate with a single I2C channel.

    Warm Regards,

    Prahaladh S

  • 0 in reply to Prahaladh S
    TI__Expert 7540 points

    Hi Prahaladh,

    We can change the MCF8329A's I2C address through I2C interface only. Is the device SPEED/WAKE pin connected to external microcontroller?

    Thanks,

    Dhinesh

  • 0 in reply to Dhinesh
    Intellectual 350 points

    Hi Dhinesh,

    Yes. The Speed / Wake pin connected to an external microcontroller.

    We're able to access the MCF8329A through I2C. Some changes were made in code.

    Suggest us ways to change the I2C address.

    Best Regards,

    Prahaladh S