bq40z50 can't charge

Hi all,

I am facing a problem that can't charge  2-Series Li-on battery with bq40z50 and bq24735.

In 0x16 BatteryStatus():  error code is UnknownError. OperationStatus()[XCHG] = 1 and OperationStatus()[XDCHG] = 1. So, I found in 4.12 Charge Disable and Discharge Disable section but I can't find any conditions that the device can disable charging. These are value of some registers:

+ 0x0054 OperationStatus: 0x6921 (charge and discharge: disable - SAFETY mode status: active - SECURITY mode: full access - System present low: active)

+ 0x0055 ChargingStatus: 0x0402

+ PF alert: 0x00

+ PF status: 0x00

+ Safety alert: 0x00

+ Safety status: 0x08000000 (Undertemperature During Discharge: detected)

+ 0x16 BatteryStatus():  0x00C7 (Error Code: UnknownError)

Thanks for any help.

Phien

PS: This is technical ref of bq40z50 that i used: www.ti.com/.../sluua43a.pdf