STM32L412CBT6 controller interfacing with SPI-Fatfs-SD with battery power 2.8 volts. SD card detecting but f_open couldn't open a file and show an error. With same application working with regular power supply(2.8 volts)

[JRUDR.1]

I am Using STM32L412CBT6 controller in that the application working with a regular power supply 2.8 volts but with a battery the remianing modules(i2c/RTC) but in SPI F-open is not working

[Vangelis Fortounas]

Hello

Used LDO is for 200mA . Is the current in mA consumed by the SD card (as per user manualn) less than (200- Imcu)? Imcu is the MCU operation current

Check the 2.8V rail for voltage drop during SD transactions.