• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 49 subscribers
  • Views 955 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

INA220: trigger mode time limitation

Yu Geng
Prodigy 130 points

Part Number: INA220

Hi,

    I have a question about the INA220 application.

If I have one I2C bus with three INA220 as slaves, can I trigger each of them without stop sign in the coding in a interleaved way?  I want to read out the information from three power monitors in an interleaved way while I want to update the power information in these power monitors every 5ms without the stop sign leading timeout (28ms). Otherwise, the power monitor will be frozen for a long period of time without updating the new information.

Best

Yu Geng

  • 0
    TI__Genius 15770 points
    Hi Yu,

    Allow me some time to review your question and get back to you.

    Regards
  • 0
    TI__Genius 15770 points

    Hi Yu Geng,

    The "stop sign" you are referring to is the STOP bit in the I2C communication? If so, you can't do that. Each device have its own address and you need to talk to each of them one at a time. 

    Regards

  • 0 in reply to Mayrim Verdejo
    Prodigy 130 points
    Hi Mayrim,
    I'm trying to implement multi device sensing in two ways:
    1. with arduino I2C bus, I can read out the power info from INA220 in an interleaved way
    2. with FPGA spartan3, I can have independent I2C lines for different devices.

    Do you mean that I need a stop bit once I want to switch communication from one device to another. Thus, arduino I2C sharing strategy may not work.
    However, if I can use FPGA, for each I2C bus, I can keep updating the power infomation from each INA 220 without stop bit.

    Am I right?
  • 0 in reply to Yu Geng
    TI__Mastermind 26405 points
    Dear Yu Geng,

    The 28ms timing you are referring to is a timeout for the SDA line that will only trigger if the line is pulled low for that amount of time. If you do the following, you should be able to read from all three devices:

    - Write to change the register pointer of each device to point to the power register
    - Read from each register in sequence

    I checked in with design, and they said that you should be able to omit stop bits between the transmissions as well, only sending a stop bit when you wish to shut down communication.

    Hope this helps,

    Carolus
  • 0 in reply to Carolus Andrews
    Prodigy 130 points

    Dear Carolus,

              I really appreciate your help! Let me try it and check whether it works.

             Thanks a lot!

    Best

    Yu Geng