SDA on bq78PL116 held low by slave always.

Bruce Appleton

Other Parts Discussed in Thread: BQ78PL116, BQ27541

Hello,

I'm having an issue with interfacing to a bq78PL116. I have two identical battery packs. One works fine with the GPIO USB adapter from TI and the other not. The second pack use to work....voltage on the SDA and SCL pins have never exceeded 5V.

The SDA line is pulled low by the slave(PL116) all the time! The pack is charged. The SCL line is high.

The GPIO tool has pull up resistors.

Any Ideas?

Thanks ,

Bruce

over 11 years ago

0 ThomasCosby over 11 years ago

TI__Guru 73830 points

Bruce,

It looks like the firmware may have gotten into a bad state, because the device should not hold the SDA signal low for an extended length of time. You can try resetting the device to see if the device recovers, indicating that it is a firmware issue. You should be able to pull the RSTN pin low on the PL116 or temporarily short VLDO1 to GND on the PL116 to reset the device. It it does not recover, then there is probably a device hardware issue.

Tom

0 Bruce Appleton over 11 years ago in reply to ThomasCosby

Prodigy 140 points

Hi Tom,

The problem is the battery pack is sealed (in a housing). I think you know the application. Only pins to my disposal are: SDA, SCK, EFCID, EFCIC.

Any ideas?

Bruce

0 ThomasCosby over 11 years ago in reply to Bruce Appleton

TI__Guru 73830 points

Bruce,

We do not have another method to reset the device. You may have to open the housing.

Regards

Tom

0 Bruce Appleton over 11 years ago in reply to ThomasCosby

Prodigy 140 points

Hi Tom,

I traced it back to an ESD package that has failed, pulling the line to ground.

Thanks again.

0 Kuge Luo over 11 years ago in reply to Bruce Appleton

Prodigy 35 points

have you solved the problem?

i have the same problem with you.

i program the DFI file to the betary,

then the BQ27541 held the SCL and SDA all the time,

i can't comunication with it any more.

i have tryed to remove the Pack,but after power on,the SCL and SDA are hold again.

0 Bruce Appleton over 11 years ago in reply to Kuge Luo

Prodigy 140 points

Hi,

In my case it was ESD protection on the clock and data lines that had blown. This pulled the lines low. If you don't have any ESD protection before the IC i think it maybe a damaged IC.

BRuce

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SDA on bq78PL116 held low by slave always.