Hi all, I'm using a STM32F215 MCU with a supercapacitor (like XH414HG-IV01E;SEIKO) connected to Vbat through a 0 Ohm resistor in order to backup RTC registers. I attach an image:
Well. If I measure the voltage in VBAT pin, it shows 0.18V. If I remove the 0 Ohm resistor, VBAT pin measure 1.18V.
My doubts are:
1. How exactly VBAT pins works?
2. VBAT pins charge the supercapacitor itself?
3. Should I control VBATE register to charge the supercapacitor?
4. Does my schematic wrong?
Thanks in advance.