Card Not Mounted - Cannot Get SD Card to Recognize with SD Module / SPI Mode

[reynolds087]

Hi, All.

I am new here, and hoping someone can help me out. I have been trying for two days to get an SD card to be recognized with the ESP32. I've tried brand new ESP32 boards out of the box, I've tried brand new SD modules (I bought a pack of five), and even a different SD library in Arduino IDE (sdFAT). Nothing has worked. The card always fails to recognize. I am using the default pins, but I've also tried other chip select pins with no luck. I tried a loopback test on the SPI interface which passed. My SD card (8GB) works perfectly in Windows, and I've tried formatting it to many different sector sizes (FAT32), including the default. It behaves like a normal SD card in the PC, no issues whatsoever. I even tried using one of those SD to SD micro adapters and soldering directly to the pins and still can't connect to it. On YouTube, people are connecting to them with breadboards, so I am fairly confident at this point it's not an issue with inductance or noise. I did also try a separate power supply and had a web server that would tell the status of the card and a button to attempt to reinitialize it, but it failed that way too. I was thinking maybe the USB was interfering with it, but the web approach made no difference. I don't get it because I tested a working SD and ESP 32 module that I used to use with FluidNC, a machine interface that uses an ESP32 as a CNC controller, and in that platform it worked with the SD card, but trying the SD test program in Arduino IDE it fails.


I also tried connecting an oscilloscope to all four wires and I could see some complex interactions happening, but don't really know what to look for. And I've already tried every SPI mode as well.I did try another SD card, but it's 128 GB, and formatting to FAT32 was a pain. I managed to do it in Rufus, but my plan is to test with a 4GB card when it arrives today from Amazon.

Aside from the off possibility that my 8GB card has failed AND my 128GB is incompatible despite being formatted to FAT32, where do I go from here if the new 4GB card fails? I feel like I need a sanity check because everything seems right but it just won't mount the card successfully.

[lbernstone]

That sd module looks like it is designed for 5V power (like an Arduino Uno). You want one that has nothing but passive components on it (or maybe has pins labelled 3V and 5V).

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