ESP32 - Can't connect to microSD card

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Joined: Sat Jun 13, 2020 12:04 am

ESP32 - Can't connect to microSD card

Postby _Savoy_ » Sat Jun 13, 2020 12:06 am

Looking for help!

I'm not able to connect the a microSD card with the ESP32. I AM able to connect to the same card/reader with an Arduino Uno, so I know the the card and reader are OK.

When I try to connect I get the following

Code: Select all

[W][sd_diskio.cpp:491] ff_sd_initialize(): READ_OCR failed: 0
[E][sd_diskio.cpp:739] sdcard_mount(): f_mount failed 0x(3)
I'm using the default ESP32 SPI pins:


I have looked at tons of posts across the internet, but have not been able to get this to work. Any ideas?

Posts: 2
Joined: Mon Aug 20, 2018 3:51 pm

Re: ESP32 - Can't connect to microSD card

Postby XTronical » Sun Jun 14, 2020 7:31 am

The SD Card board probably has a 3.3v regulator on it. Bypass it as it will not function correctly when supplied with 3.3v only something above that like the Arduino's 5V. See this video I did showing the "bodge" I made when I came across this problem recently, the link takes you right to the correct part of the video :

Posts: 3
Joined: Sat Apr 18, 2020 12:03 pm

Re: ESP32 - Can't connect to microSD card

Postby markdh102 » Thu Jun 18, 2020 9:34 am

I use one of those adapters that comes with every MicroSD card. I solder header pins to it so it will fit onto a Veroboard.
Works on the ESP32 @ 3v3 no problem as there's no electronics on the adapter...

Posts: 17
Joined: Tue Sep 05, 2017 1:43 pm

Re: ESP32 - Can't connect to microSD card

Postby ilioss » Thu Jun 18, 2020 6:45 pm

Hello to ALL,

Stop surging for trouble with micro SD card sheeld.
This post realy solved my problem.
NOT POSSIBLE TO initialize.
After desoldering and place the link it works like a charm.

ilioSS :D

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