How to read Safety status register correctly?

Bump. Can someone please help? Our project has been paused because of this issue.

Karlis,

SMBus command 0x51 is the correct command to read the SafetyStatus register and I checked the waveforms on my EVM using the bqEVSW to communicate with the device. I found the response to be correct. Do you have a scope capture with the clock to verify the data?

Tom

bq3060 SafetyStatus.pdf

Hi Tom.

I just made some screenshots. It read the 0x51 register but the value is wrong. You can check the screenshots in the attached file. 

I still have no idea about this. I can read values like voltage, current, SOC etc. correctly.

smbus safety status read.pdf

Karlis,

Your waveforms do show that the gauge is reporting 0x0019 for the SafetyStatus. The rise time on the waveforms is slow and we have had customers report seeing erroneous data with slow rise times. Is your ESD protection very capacitive? You could try removing the ESD protection devices or reduce the pull-up resistance to sharpen the rise time to see whether this helps.

Tom

I am using ESD diodes with 15pf capacitance and 10k pull up resistors. Regarding your suggestions I can't really understand why can I read other values correctly but not this register.

I will try lower pull ups and no ESD devices and report back.

Karlis,

That's good to hear. Thanks for letting me know.

Tom