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EV2400: Questions regarding using Battery Management Studio with EV2400

John Pierson
Prodigy 105 points
Part Number: EV2400
Other Parts Discussed in Thread: BQ25731,

Hello,

I am trying to use a TI EV2400 USB to I2C interface. I am using Battery Management Studio v1.3.111 (Device - bq2573x) Charger_1.00_bq2573x.bqz. I am unable to reliably read the registers from the BQ25731 device. The only documentation I have been able to find on how to operate this program is in the TI - BQ2571x Evaluation Module Users Guide sluubt8b.pdf. It only states: "After selecting the target device, change “update mode” from “immediate” to “manual”, click “Read Register” and the following interface is presented." I have updated the EV2400 firmware using the EV2400Updater-0.32-windows-installer executable. I have checked to see if there is any interfering I2C traffic that might be interfering with this, but have not found anything.

Occasionally, I am able to read the registers. But most times, nothing happens. And I have been unable to write to any register. Is there any better documentation available for this software? Or do you see something I am doing incorrectly?

Thank you, John

  • 0
    TI__Guru 57697 points

    Hello John,

    For bq25731 EVM use this guide www.ti.com/.../sluucb9

  • 0 in reply to Shirish
    TI__Guru 57697 points

    If you are having trouble reading the register(s) then you will see an error code in red. Example of Nack error below.

  • 0 in reply to Shirish
    Prodigy 105 points

    Hello Shirish,

    I downloaded the BQ25731 EVM User Guide. This does not explain how to write a register. So this does not resolve my issue.

  • 0 in reply to Shirish
    Prodigy 105 points

    Hello Shirish,

    This is the main problem I have been having. This is error is almost always present. Sometimes, when I plug in the USB cable, it then reads all of the BQ25731 registers. I have used a scope to look at the I2C signals and the levels and edges look solid. And there is another Master on this I2C bus, but it is not active. It is OK to have two Master I2C devices on the I2C bus - as long as only one is operating. Do you have any other ideas of what might be causing the Device ACK Error issue?

    Thanks, John

  • 0 in reply to John Pierson
    TI__Guru 57697 points

    Hello John,

    To write a register, type in the new value and click the write button

    If there is another master, then check if there are additional pullups. The total effective pullup may have been altered and could be out of spec. Also many masters continuously poll the bus, so make sure that the other master is truly not active. You can remove the bq27531 and check if the master is sending out communication when it is supposed to be inactive.

  • 0 in reply to Shirish
    Prodigy 105 points

    Hello Shirish,

    Thank you for your response. The I2C and I2S signals on our board are 2.2 kOhm pullups to 3.3V. These are low resistances for I2C pullups. And I expect the EV2400 Has it's own pullups. This may be the issue. Additionally, I will check to insure our MCU I2C Master port is truly not active. I will test this and get back to you.

    Thank you for your support. John

  • 0 in reply to John Pierson
    Prodigy 105 points

    Hello Shirish,

    I have verified that our MCU is periodically reading and writing data on I2C bus I was trying to get the EV2400 to work on. So this explains why I am having issues with the EV2400. We will have to address this in our MCU firmware.

    Thanks for your support! I will close this case now. John