BQ40Z50: RDIS bit clearing

Ian Aherne

Part Number: BQ40Z50

I am trying to observe an RA table update by monitoring the RX bit in the Gauging Status register while discharging the battery, the RDIS bit is set constantly so I cant observe the update.

The update status register is 0x0E

I noticed when using BQ studio gas gauging is enabled by default ( I presume BQ studio sends a command to enable it on startup as the TRM says gas gauging should be disabled), if I disable gas gauging wait a second and then re enable gas gauging again the RDIS bit will clear.

This creates some uncertainty as I am now not sure if the RDIS bit is set due to incorrect gauge enabling or for another genuine reason.

Regards

Ian

over 1 year ago

0 Jose Couso over 1 year ago

TI__Mastermind 27321 points

Hello Ian,

Are you trying to complete a learning cycle?

If you reset the gauge, RDIS will be set. It will automatically clear after the first discharge to empty during relaxation, see section 3.2.2 in the Achieving The Successful Learning Cycle

If you have already finished the learning cycle and RDIS is being set during relax, this can mean that a negative resistance is being calculated. This might be due to wrongly matched ChemID.

Regards,
Jose Couso

0 Ian Aherne over 1 year ago in reply to Jose Couso

Prodigy 200 points

The learning cycle has been completed previously and golden image generated, this test would be using the same golden image with the same cells on a different PCB.

it would be the first discharge after power on and gauging is enabled i.e. normal operation.

in this situation what should the status of the RDIS bit be, does it need a full initial discharge before it will clear?

0 Jose Couso over 1 year ago in reply to Ian Aherne

TI__Mastermind 27321 points

Hi Ian,

Please reset the gauge and do a full discharge. It will clear during relax.

Regards,
Jose Couso

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BQ40Z50: RDIS bit clearing