BQ27426: Does the data in TRM's extended instructions change during application?

Hello Wang,

1. Register values are meant to change. The different registers report different values and depending on conditions will have different values. Some registers are write only. See TRM Table 5-1. Standard Commands

2. Assume that all values can change. There are some registers that will not change but unless stated in the TRM, do not assume that those are fixed

3. Same as #2

4. Most of the commonly read registers will change. If you have concerns, then let us know which registers your application will read and we can comment.

Thanks for you reply

#1--#3、The data in Standard Commands changes, we understand that.

#4、Does the data in Externed Commands change?
Which specific registers will change during FuelGauge operation after FS file is loaded?

We need to read all the data in Externed Commands to check the write value and read back value, which is used to prevent the data in Externed Commands from being modified accidentally (various disturbances). So we need to know which data in Subclass ID of Externed Commands will be actively modified during runtime? Which ones will not be modified? Please tell us the corresponding Subclass IDs, thanks!

Extended Commands are intended to read configuration while the gauge isn't gauging. You will risk a watchdog timer reset, if you read configuration data too often. There is no requirement from the gauge to read configuration while the gauge is gauging so I don't understand the requirement to check, if data was modified accidentally. I recommend sealing the gauge - this will prevent any changes to data memory and the configuration.

Thanks for you reply。

The reason to read back the confirmation is: the device has high security requirements, and the device is used in occasions where there is more interference of various kinds, and I am afraid that because of the interference, the Fuelgauge's configuration will be abnormal during the operation.

I mentioned in another question: Is it possible to guarantee that the data memory of Fuelgauge will not be changed in the case of various disturbances in the SEALED state? Is there a basis for this?

The basis for this is that there is no regular path for the data to change. Of course, if external conditions (e.g. electrical disturbances, glitches on supply, extreme EMI, ESD) cause actual electrical problems inside the gauge, then it's not guaranteed that data memory contents won't change.

Thanks for you reply.

Back to the previous question:

We need to read all the data in Externed Commands to check the write value and read back value, which is used to prevent the data in Externed Commands from being modified accidentally (various disturbances). So we need to know which data in Subclass ID of Externed Commands will be actively modified during runtime? Which ones will not be modified? Please tell us the corresponding Subclass IDs, thanks

Thanks for you reply

1、Does the chem id data change during FuelGauge operation, except for Ra, State, Chemistry and Calibration (CC Offset) which may change?
2、Can you tell me what is the class and subclass of the chem ID corresponding to subclass id 83, 84 and 85 respectively?

#1: No.

#2: This is not public information. I can't share this on a public forum.

I'm sorry, but I'd like to ask you again to confirm that the following chart shows the result of comparing Ecmm with the Fs file we used at the beginning

Will the new Subclass IDs 53(block00\01), 54, 55, 68(block00\01), and 69 be changed after the fs file is loaded and the fuelgauge IC is running?