BQ41Z90: Unseal device

Hello Pooja,

This question has been assigned and will be answered promptly.

Thank you,
Alan

Hello Alan,
I am following up on this. I would appreciate any update you can provide regarding my query.

Hello Pooja,

I would reference section 12.7 for step to step to unseal your device within the Technical reference manual.

Technical Reference Manual:
https://www.ti.com/lit/ug/sluud63/sluud63.pdf?ts=1743801875593&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ41Z90

Thank you,
Alan 

I am facing an issue with the BQ41Z90 device where the SMB data line breaks intermittently during operation, causing the device to disconnect. When it reconnects, which happens every few seconds, the device gets sealed again. Due to these frequent reconnections, I am unable to unseal the device in time to carry out the necessary operations.

Could you please provide guidance on:

1. The procedure to unseal the device effectively in this situation. Additionally, it would be helpful if you could share a screen recording of the unsealing process as an example. This might assist in diagnosing the issue more effectively.

2. Troubleshooting steps to address the SMB data line disconnection issue to prevent repeated sealing.

Your assistance in solving these problems would be greatly appreciated.

Hello Pooja,

Before answering your question I wanted to go into depth with your battery gauge setup. 

-Are you using a EVM or a custom PCB?

-If you are using your own pcb can you first try to unseal your gauge on the EVM

-Can you send me your schematics to review your pcb if you are using one.

Thank you,
Alan 

Hello Alan,
I am using EVM and EV2400. Moreover, I would like to add that J21(I2C) Port is also not working. I am unable to communicate via I2C protocol. While communicating via SMB, I am getting the message "No Acknowledge from the device" at the bottom of bqstudio, after every 2-3 scanning cycle.

Hello Pooja,

Pooja Agarwal said:

I am unable to communicate via I2C protocol

Firmware development for bq41z90 is an ongoing process, at the moment the current FW version of BQ41z90 does not support i2c, currently there is no time table for when the next fw update will be released. However we advise to use SMBus communication in the meantime.

Thank you,
Alan

Hello Alan,
While communicating via SMB, I am getting the message "No Acknowledge from the device" at the bottom of bqstudio, after every 2-3 scanning cycle. I am unable to communicate continuously via SMB also.
Thank you,
Pooja

Hello Pooja,

The only thing that would make sense for this happening is due to your hardware setup. Please make sure you are making good connection, the wires are in working order, and that your EV2400 is functioning. I would start changing out cables, debugger and EVM's to see what is causing this disconnection. We haven't seen other customers with this issue and I've attached the EVM for help.

EVM:
https://www.ti.com/lit/ug/sluud64/sluud64.pdf?ts=1746048766619&ref_url=https%253A%252F%252Fwww.ti.com%252Ftool%252FBQ41Z90EVM

Thank you,
Alan