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BQ20Z45 SOCC permanent failure clear

DAN55143
Prodigy 55 points
Other Parts Discussed in Thread: BQ20Z40, BQ20Z45

I am using proprietry software for programming the BQ20Z45 and I have accidentally written the wrong value to the charge CFG register in the BQ20Z40.

Battery discharged fine but when I wen to charge it failed, and now there is a PFflag that I cannot clear.

it is the SOCC permanent failure, and I cannot seem to write the PF key to clear it.

battery voltage(0x09) is higher than flash update OK (not that this should be an issue) and pack voltage reads zero volts.

 

Does anyone know the exact process for writing the PF clear key? I think I had success with it last year, but cannot seem to reset it.

I have set the  PF clear key to FF FF FF FF, to make sure endianness was not a problem.

I believe I need to send the following:

start bit, slave address, write bit, <ack>, 00 (MAC), <ack>, FF, <ack>, FF, <ack>, stop bit

start bit, slave address, write bit, <ack>, 00 (MAC), <ack>, FF, <ack>, FF, <ack>, stop bit

but this is not clearing the fault. Am I supposed to leave out the first stop bit?

 

the above method does not make sense to me. suppose I set the PF clear key to the same as the  reset command  (00 41 00 41), or some other MAC command , then when I entered this to clear the PF, the device would just reset twice!

 

Has anybody else managed to reset the PF using proprietry software?

Cheers

  • 0
    Prodigy 55 points

    Sorry, I meant to type BQ20Z45 in the above entry, not BQ20Z40.

  • 0 in reply to DAN55143
    TI__Expert 3865 points

    You cannot set the PF key to any of the existing command like 0x0041 (which is a reset command).

    I don't think you successfully set the PF key to 0xFFFF because it is actually an existing command. I'm guessing your PF key is still set to its default value. Please send me a private message with your email and I'll send you the default value to try out.

    When you try to clear the PF, make sure the fault is removed, otherwise the PF will be set again as soon as it gets clear.

  • 0 in reply to Jackie Hui
    Prodigy 55 points

    Hi Jackie, thanks for your input, please pardon my ignorance, but I am not sure how to send a private message! I assume I need to add you as a friend.

    When I read back the PFkey from register 0x62 it reads 0xffffffff, which is the maximum value according to the datasheet, but I suspect you may be correct.

    There is defiantely no charge current being applied, and there is no load being applied to the teminals (I am communicating via smbus with the battery sitting on the bench), so the SOCC fault should be cleared.

    Are you able to send me a private message so I can give you my email address?

    Cheers

    Dan