I currently have a project im working on that consists of a Pro Mini, WaveShare 4.2" e paper display, TinyRTC, RFID reader - RC522 and Micro SD card reader.
Everything is working fine except for the SD card reader. when i plug it in directly to the 3.3v of the pro mini it doesnt work. When i plug it into an external 5v supply, it does but the RFID reader stops working.
Any thoughts on why this is and how can i fix it? link for the SD card reader is here: SD Card Reader
And link for RFID reader: RFID Reader
Is it possible that the SD card reader is sending 5v to the SPI pins causing the RFID reader to not work properly? Is there an easy way to fix or is there any sd card readers that use native 3.3v instead of having a regulator on it?
PS: i tried removing the regular from the sd card reader and jumping the connection to have straight 3.3v go to the cards but it doesnt work either.
Any help is greatly appreciated.