With the help of a free, open source application, you'll be able to read The Cid of any SD card in less than five minutes. SD cards are used to provide expandable storage to a huge range of devices ...
This example demonstrates how to use an SD card with an ESP device ... hello.txt to /sdcard/foo.txt I (7396) example: Reading file /sdcard/foo.txt I (7396) example: Read from file: 'Hello XA0E5!' I ...