BQ27Z746: How to calculate the checksum value for address 0x60?

Tom Tsao

Expert 1850 points

Part Number: BQ27Z746

Tool/software:

Hello TI Support Team,

I am currently learning how to change the Security Key in the TRM.

I would like to ask about the detailed steps.

First, I write to 0x3E:

[35 00 23 01 67 45 AB 89 EF CD 44 22 31 21].

Next, I write to 0x60:

[0A 0C]

Where 0x0C represents the data length [23 01 67 45 AB 89 EF CD 44 22 31 21] => 12 bytes, is this correct?

Does 0x0A represent the checksum value? How is it calculated? Isn't this value 0x52?

Thanks!

0 Alan Frias 5 months ago

Hello Tom,

Please reference this application note for helping program authentication keys.

Thank you,
Alan

0 Tom Tsao 5 months ago in reply to Alan Frias

Expert 1850 points

Hi Alan,

I believe authentication keys and security keys are different types.

My question is simply to understand how the checksum value 0x0A was calculated in the security key example from TRM.

[35 00 23 01 67 45 AB 89 EF CD 44 22 31 21] => Checksum=0x0A ,Data legth=0x0C

Could you provide the detailed calculation steps?

Thanks!

0 Adrian 5 months ago in reply to Tom Tsao

Hello Tom,

Regards,

Adrian

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