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INA223: Question of INA223's Pointer Address

Wayne Chen (ex FAE)
Guru 15950 points
Part Number: INA223

Hi Sirs,

According to the INA223 datasheet, there is only one configuration register thus there should be only three data frames for I2C write. Would you pls advise if the frame 2 register pointer byte a mistake and should be removed from the chart?

Or, would you pls advise the definition of P[7:0] and how to configure them? 





Thank you and Best regards,

Wayne Chen
10/20/2017

  • 0
    TI__Mastermind 26620 points
    Wayne,

    I believe the P[7:0] byte is the actual register location of the Configuration Register. This byte actually specifies that you are writing to the configuration register. The first byte is just our devices address to distinguish that you are writing or reading to our part and not another device on the same I2C bus line.

    Let me confirm this though.

    Peter Iliya
    Current Sense Applications
  • 0 in reply to Peter Iliya
    Guru 15950 points
    Thank you Peter.

    There is only one configure register and only one byte for it, thus I think there should be two data frames for INA223’s I2C write - Device ID with Write bit = low, Configure Data with one byte. Would you pls assist me to confirm it?

    I will apply an EVM to check it by an I2C analyzer simultaneously, while customer needs our information to write their software urgently.

    Thanks a lot

    Wayne Chen
    10/21/2017
  • 0 in reply to Wayne Chen (ex FAE)
    Guru 15950 points

    Hi Peter,

    I checked the EVM's waveforms, the pointer should be 0x0 and data's MSB should be 0x0 as well. Here is the example to write 0x61 to the INA223:



    Thanks a lot,

    Wayne Chen
    10/23/2017

  • 0 in reply to Wayne Chen (ex FAE)
    TI__Mastermind 26620 points
    Wayne,

    After speaking with my team, the datasheet does not mention the pointer address for the configuration register. Although we have only one configuration register, we still have to write the P[7:0] in frame 2 byte to write to it. Make sure you write all zeroes to this register when you write any command to the configuration register.

    So you are correct that "the pointer should be 0x0" and I apologize for the confusion.

    Peter Iliya
    Current Sense Applications
  • 0 in reply to Peter Iliya
    Guru 15950 points
    Hello Peter, Addition, do we have plan to add this description to the INA223 datasheet thus we don't need to explain it to customers for every single case? Thanks a lot...Wayne Chen
  • 0 in reply to Wayne Chen (ex FAE)
    TI__Mastermind 26620 points
    Wayne,

    We do have a plan to evaluate the datasheet and make this correction.

    Peter Iliya
    Current Sense Applications