Problem with BQ20Z70

Are you using PEC with your master on the bus?  I strongly recommend this.   Is this your design that is master of the bus or are you using the EVSW and EV2300?  There is nothing in the part that I can think of that would cause this.  The clue you are saying to me that gives the most is that it is 0xffff which probably means if this is your design (master) that the transaction failed somewhere during the communication and the 20z70 is just floating the bus, or your host gets the failed communication and just doesnt put anything in its receive buffer so you see 0xffff as default.  I would say use a scope to look at the communications and see if you can find an issue with it.  Try to find something in your host that happens on a 1 second interrupt and make sure to disabled interrupts around the communications or put some error handling around the communication if you had to abort it if the 1 second interrupt cannon be disabled for a couple of milliseconds.  Attached is an apnote on how to troubleshoot smbus

Thank you, using PEC help me, but now I have a problem: when charging close to end, Permanent Failure happens with PFStatus 0x0100 i.e. Permanent AFE Communications failure according to SLUU250A, what is this ? I can't find a description of that failure.

I'm using BQ20Z70-V110 and BQ29330.