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Bq27541, to go to Unsealed state

Rhino
Prodigy 190 points
Other Parts Discussed in Thread: BQ27541

Dear All

 

I have a question on bq27541.

 

I can’t find the way to go to “unsealed” from “sealed”.

 

Please let me know the method to go to “unsealed”.

 

Best Regards,

Rhino

  • 0
    TI__Intellectual 2100 points

    Rhino,

    You will send the gauge to SEALED mode by sending command 0x20.  From the log on your other post about going to FULLSLEEP, it appears that your gauge is already in SEALED mode.

    To unseal your gauge, you will need to enter the UNSEAL command into address 0x00/0x01.  The default is 0x36720414.  This is entered by sending the data 0x0414 to address 0x00, and immediately thereafter sending 0x3672. 

    Once this has happened, you will then need to clear the FAS (full access bit) to allow full access to your gauge.  This is done by doing a similar step using the full access command.  The default here is 0xFFFFFFFF. It is entered in an identical manner as the unseal key above.

    Once this has happened, you must note the following.  Since you have sent the SEALED command, the gauge has stored this information in a non-volatile location.  The above method of unsealing the gauge clears a RAM bit.  Therefore, if the gauge power cycles or resets, the SEALED bit will set itself again.  The only way to completely clear the SEALED bit in a persistent manner (until you send the SEALED command again) is to reflash the firmware AND data flash image.

    Let me know if this helps,

    Charles