BQ76952: Communication problem with fuel gauge and battery monitor

Ignas Vaiciulenas

Part Number: BQ76952
Other Parts Discussed in Thread: BQ34Z100, EV2400, BQSTUDIO,

Hi all,

We are building a battery pack with BQ34Z100 fuel gauge and BQ76952 battery monitor. Currently, we are facing a communication problem while trying to connect with EV2400 trough I2C. Computer detects the fuel gauge just fine, however, we cannot connect to the battery monitor as it always detects the fuel gauge but not the monitor.

Both devices are sharing the same SDA and SCL lines. As I was absolutely out of ideas why it won't connect, I tried to cut SDA line going to the fuel gauge... and it worked... I have successfully connected to the battery monitor. So, are there any reasons why these ICs would interfere with eachother? Furthermore, what could possibly be the root of this problem - firmware? hardware? something else?

Appreciate all the ideas and suggestions a lot as we have already spent a lot of time working on this problem, and do not have any ideas left!

over 1 year ago

0 Max Verboncoeur over 1 year ago

TI__Mastermind 25625 points

Hi Ignas,

See this thread for the procedure for communicating with multiple devices: BQSTUDIO: Communication with multiple devices - Power management forum - Power management - TI E2E support forums.

The devices referenced are different, but the procedure will be the same.

Regards,

Max Verboncoeur

0 Ignas Vaiciulenas over 1 year ago in reply to Max Verboncoeur

Prodigy 25 points

Hi Max!

Thank you for the answer. Unfortunately, we are facing this problem while following those steps. We always select BQ76952 monitor as the first step, and only then connect our EV2400 module. However, we are not getting any answer from the monitor.

Anything else what we can try changing in the parameters, or something what we should take a look at?

Regards,

Ignas Vaiciulenas

0 Max Verboncoeur over 1 year ago in reply to Ignas Vaiciulenas

TI__Mastermind 25625 points

Hi Ignas,

Just to confirm, you are disconnecting the EV2400 from the I2C lines on the devices while keeping the computer connected and choosing the monitor, and then reconnecting the I2C lines to the EV2400?

Regards,

Max Verboncoeur

0 Ignas Vaiciulenas over 1 year ago in reply to Max Verboncoeur

Prodigy 25 points

Hi Max,

At this point I have tried both options: disconnecting only the I2C line, and disconnecting the EV2400 from the computer. Unfortunately, neither of those options brought any results.

Regards,

Ignas Vaiciulenas

0 Luis H. S. over 1 year ago in reply to Ignas Vaiciulenas

TI__Mastermind 42060 points

Hello Ignas,

What was your exact sequence?

I tested on a couple of our boards using a single EV2400 to test it out.

Every instance of bqStudio needs to have Auto Refresh disabled (see image below). You also have to ensure that the EV2400 is connected first, so that bqStudio detects the EV2400.

Once disabled and both bqStudio instances open for each device, I found that you need to re-connect the USB from the computer every time you want to communicate with the other device. Not a very pretty solution, we'd have to see if there's a better solution there.

If you have two EV2400's, you'd be able to communicate with both devices easily by connecting each EV2400 to a different USB port. The BQ76952EVM has one EV2400 on-board.

Best Regards,

Luis Hernandez Salomon