How to integrate MFRC522 and SD card module and make them work together on ESP32 Devkit V4?

[van_der_decken]

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Issue with some SD Cards when used with another SPI Device

Summary: The MISO output of this board is always active, regardless of the CS state. Because of this any other devices on the SPI buss will not be able to communicate back to the master. Alone this board works fine. Desc. I tried to use the SD Card shown below with a Pro Mini and another SPI device with no success. This board is advertised as a 5.0V board that interfaces with 3.3v SD cards. It contains a 5V to 3.3V regulator and a level shifter. The issue with this board is the level shi…

Mind you, I've looked at your code and it doesn't reference the SD library anywhere. So the fact that you've gotten to the SD card to work at all with no code to enable it/select it/write to it is something of a miracle.