BQ40Z50: unable to write to battery mode register

user5018898

Part Number: BQ40Z50
Other Parts Discussed in Thread: EV2400

Hi,

I having an issue in writing to the Battery Mode register using my sealed battery. I have tried writing to some of the other registers that are accessible when the battery is sealed (Remaining Capacity Alarm, Remaining Time Alarm, and At Rate) and those writes were successful. We checked the Battery Status register before and after attempting to write to the Battery Mode register but an error code was not ever set like I would expect to.

Is there any reason why this one particular register would not allow writes when sealed, as i see in section 12.4 of the tech reference manual this register is R/W under all cases?

Thanks,

Jose

over 4 years ago

0 Jessica H. over 4 years ago

TI__Genius 11535 points

Hi Jose,

What are you trying to write to BatteryMode? Also, which error code were you expecting to see?

0 user5018898 over 4 years ago in reply to Jessica H.

TI__Intellectual 770 points

Hi Jessica,

The initial configuration has the register set to 0x6000, and the software is trying to change it to 0x0000.

Thanks,

Jose

0 Jessica H. over 4 years ago in reply to user5018898

TI__Genius 11535 points

Hi Jose,

Which error code were you expecting to see? Is the register 0x6000 or 0x0000 when you try reading it back after writing to it?

0 user5018898 over 4 years ago in reply to Jessica H.

TI__Intellectual 770 points

Hi,

Since there was no acknowledgement of the command I just expected some error flag to be tripped but there was none in particular I would point to. Since it is i2C it is difficult to tell an intentional NACK from a no response.

It looks like the register is reading back the updated value as the bytes for the transaction were acknowledged up until the last byte. Is this intentional behavior from the battery pack?

Thanks,

Jose

0 user5018898 over 4 years ago in reply to user5018898

TI__Intellectual 770 points

HI,

I was mistaken. The register does not read back the updated value of 0x0000, and instead reads back the original value of 0x6000.

Thanks,

Jose

0 Jessica H. over 4 years ago in reply to user5018898

TI__Genius 11535 points

Hi Jose,

Are you using EV2400? Can you take a picture with a logic analyzer of a successful write and the failed write?

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BQ40Z50: unable to write to battery mode register