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BQ35100: Unsealing access to BQ35100

Part Number: BQ35100
Other Parts Discussed in Thread: BQSTUDIO

I am trying to put the BQ35100 device to Unseal mode from full access mode.

I have tried the following:

1. I2C Write 3E, 04, 14 followed by I2C Write 3E, 36, 72 - fails to unseal device

2. I2C Write 3E, 14, 04 followed by I2C Write 3E, 72, 36 - fails to unseal device

3. I2C Write 00, 04, 14 followed by I2C Write 00, 36, 72 - fails to unseal device

4. I2C Write 00, 14, 04 followed by I2C Write 00, 72, 36 - fails to unseal device

5 - 8. Writing the second part first (ie 3672) followed by the first part (ie 0414).

I noticed when reading the Unseal Codes from 0x41CC - it reports 143672FF; whereas when reading from 0x41CB - it reports  4143672. Is this offset expected ? For completeness sake, I also tried the previous 4 ways with 143672FF as the unseal key instead of 04143672.

What is the correct I2C sequence I must follow? If you could give me the exact addresses to use instead of register names, that would be very useful

  • Hi Syed,
    Do you have an EVM and bqstudio to test this out? 04143672. bqstudio has a one click button to send both commands in the sequence it is supposed to be sent. You can capture the commands on a scope to know exactly what the sequence is to help guide you.

    thanks
    Onyx