BQ40Z80: PRES pin always low

Darren Jenkins

Part Number: BQ40Z80

Fuel gauge team,

Our customer sees the PRES pin always low, even though the registers MFP17_SEL0, 1, 2 are set to b000. The only thing connected to the pin is a 100nF cap. There are no external pull ups or downs.

Are there other settings involved? What else should we be looking for?

Thanks,

Darren

over 4 years ago

0 Jessica H. over 4 years ago

TI__Genius 11535 points

Hi Darren,

Is OperationStatus[PRES] getting set? If so, that is all that needs to happen.

Best,

Jessica

0 Darren Jenkins over 4 years ago in reply to Jessica H.

TI__Genius 12481 points

Hi Jessica,

The customer says OperationStatus[PRES] is read only, and is always high.

Thanks,

Darren

0 Jessica H. over 4 years ago in reply to Darren Jenkins

TI__Genius 11535 points

Hi Darren,

The system should be working then. When PRES is low for four samples (one second), OperationStatus[PRES] is set, indicating the system is present (the battery is inserted).

Best,

Jessica

0 Darren Jenkins over 4 years ago in reply to Jessica H.

TI__Genius 12481 points

Hi Jessica,

The customer resoldered the device and removed the 100nF cap, and it now works. They can see PRES change now. I'm not sure if the problem was the soldering or the 100nF cap.

Thanks,

Darren

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BQ40Z80: PRES pin always low