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STM32F215 VBAT pin

Question asked by Francisco SinapseEnergia on May 11, 2018
Latest reply on May 11, 2018 by Francisco SinapseEnergia

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.