BQ2084-V143: Seeing AFE FAIL Bit set -> pack status 0x88h

Hi Steve,
yes that is a problem. It means your AFE. the companion chip BQ29312 has failed . You need to check to see if that chip is still functional. Did you have any of the safety flags get set? Was your pack exposed to ESD? Try issuing a reset command to see if that will clear that flag.

thanks
Onyx

The AFE appears to be working properly - see the attached word file form a couple posts back. We can read cell voltages, current & operate the CHG & DISCHG fets properly. we did notice in the MISC CONFIGURATION register that 0x0BB9h is present - that shows the AFEDET bit set to 0 so that disables the AFE communications check. How do we verify the AFE is bad (if it is bad)?

Onyx -

Please review the dataflash screen shots in the above attached word file - will this battery pack go to sleep? I see that Vpack threshold is set to 0

Steve
We checked the firmware and this is how the AFEFAIL detection works. You have the AFE FAIL LIMIT set to 256, so if the gauge detects a communications issue over 256 times, then it sets the AFEFAIL flag. If the AFEDET bit is set to 0, then the AFEFAIL bit cannot be cleared. If the AFEDET bit is set to 1, then the AFEFAIL bit will be cleared and the gauge will blow the fuse, if it detect another communications issue. The AFEFAIL bit indicates that there may be lingering communications issues in the pack and that is is able to recover on its own.

Tom