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INA233: INA233 PMBUS drivers over regular I2C

Giulio Zoppi
Intellectual 645 points
Part Number: INA233
Other Parts Discussed in Thread: INA3221, , INA226

Hello,

I'm using you INA3221 for managing the telemetry (both voltage and Current)  in a custom board.I developed my set of drivers based on I2C (register r/w interactions) that grant me full control of your device. There's a particularly sensitive rail that needs a more accurate measurement; for this purpose I found another PN: INA233. Despite the fact that the device is declared as I2C Compatible  it seems that there's no way to putting in place a simple I2C - based register R/W interaction with the device (thus exploiting the INA3221 drivers). Unfortunately the Microcontroller I'm working with does not support either SMBus or PMBUS, so I guess I have to write my own PMBus stack in order to put in place a working communication.

My question is: can you see any particular problem in writing this PMBUS stack over a standard I2C bus? that should not be complicated , unless I'm missing something. I'm taking as a reference this link:www.ti.com/.../litabsmultiplefilelist.tsp

If we were able to exploit the drivers written for INa3221 that would be fantastic!!!.

Maybe you got some different PN  running with regular I2c that best fits our needs? 

Best regards, 

G.

  • 0
    TI__Mastermind 32395 points

    Hey Giulio,

    Welcome to the forum. I hope we can assist you well and in timely manner.

    I believe you are correct that your previously linked document should explain how to use PMBUS function over I2C hardware. The difference between the INA3221 and INA233 are the PMBUS commands of INA233. So when you set the pointer register for INA3221 you are specifying a PMBUS command for the INA233. So overall communication/drivers with INA233 and 3221 will be different since they do not share common registers, but the I2C hardware layer should still work for both.

    Unfortunately the INA3221 is unique power monitor with three channels, so no other devices will have similar functionality/register maps that would allow for shared drivers. The INA226 has same performance as INA233, but without PMBUS commands. You can browse power monitors here:

    https://www.ti.com/amplifier-circuit/current-sense/power-current-monitors/products.html&sort=p766max;asc

     

    Most power monitors that start with number 2 for the PN (INA2xx) will have common drivers. We have some Linux drivers that one could use here:

    http://www.ti.com/tool/INA2XXSW-LINUX

     

    Please let me know if you have more questions.

    Sincerely,

    Peter Iliya

  • 0 in reply to Peter Iliya
    Intellectual 645 points

    Hello Peter 

    the solution with INA226 is perfect for our needs, for just a minimal effort is required in order to develop its drivers from the already working INA3221 ones.

    thank you very much for your valuable support.

    BR,

    Giulio