how to send subcommand to bq27541 by HDQ?

Hello Yu

Pls review the post below. It explains how to do this on the bq27742. The procedure is analogous with the bq27541

thanks

Onyx

From the website you sent me, i still don't know how to do;

in the website you sent me,  no any answer is about how to use HDQ to send subcommand,  and i don't know which reply is correct answer;

i haven't EVSW, and i am using HDQ not I2C;

my question is how to use HDQ to send subcommand?

any step should i follow?

any documents explain how to use HDQ to send subcommand?

any example codes explain how to use HDQ to send subcommand?

I don't find any documents or examples about my questions in TI website, it's very strange;

TI has some documents that explain how HDQ works, and how to implement it. (see SLUA408A).

As for sending Control subcommands, see my forum post here (it has a small example code snippet that shows what data to read/write to the fuel gauge): https://e2e.ti.com/support/power_management/battery_management/f/180/p/359052/1435869#1435869

I have a couple questions to ask you, however.

• Are you using a pre-made battery pack (for example, an iPhone battery for use in another project), or developing a new battery pack?
  • For development and testing, an EV2300 or EV2400 USB-to-I2C adapter and TI's bqStudio software is used to interact with the fuel gauge (viewing/logging data, editing the on-chip configuration memory, etc.), and TI's fuel gauges require some configuration before they can be used.
• What application are you planning to use the bq27541 for?

If you have any more questions, feel free to ask!

Thanks

I have tried this way to send subcommand, but I can't read the right Device ID;

But I send standard command, I can get the right value, such as voltage, percentage, etc...

I don't believe the many TI members don't know how to send subcommand at all,  and there isn't a document to tell us how to send subcommand, it's a big surprise!!!

If you're able to read the standard commands correctly, then something may be wrong in your setup when it comes to sending a CONTROL subcommand and reading back the result.

I'm still not sure what your current setup is. What hardware and software are you using to access the fuel gauge with?