PCF2129T Battery Issue

[fatihozen]

Hi,

I have a custom board, need a date and time datas so I am using PCF2129T with I2C communication. I am using 3.3V CR2032 cells. The problem is that, when I plug a cell lower than 3.3V, system is ok, working properly but if cell's voltage is over 3.3V all datas are being zero, all registers become 0. What could be the problem ?  You can see the schematic below, +VBAT is connected to VBAT pin of LPC54608. 

(

Tried it two different modes, results same:

000  : battery switch-over function is enabled in standard mode; battery low detection function is enabled

011  : battery switch-over function is enabled in direct switching mode; battery low detection function is enabled

)

[guoweisun]

Disconnect the VBAT with LPC54608 and promise the VDD/VBAT is always on when do this test.

[fatihozen]

It is on the PCB, How can I disconnect Vbat with LPC54608 ? Is this hardware problem ? Could be there any solution with software ?

[guoweisun]

If no power on reset event,this issue will no happen,so need you check the power path.