ESP32S3 SD-card init problem

[stefan.erni]

Hi Ben

I'm trying to initialize an SD card on a ESP32S3, but I keep getting a 255 return (no card) instead of 0 (card ok).
Is there something else I need to configure to make this work with the S3? With the ESP32 wroom32 This worked very well.

2026-04-23_16-01-33.PNG (28.17 KiB) Viewed 1389 times

2026-04-23_16-09-08.PNG (117.21 KiB) Viewed 1389 times

[BenR]

Hi Stefan,

What type of card are you using? Not every card supports the 4-bit mode, maybe try the 1-bit mode and see if that works.

We are using the 4-bit mode on an ESP32S3 in house and it is working very well but we have to be careful about which cards we use.

All SDHC or SDXC cards are suppost to support 4-bit mode but this is not my experience.

[stefan.erni]

Hi Ben

Glad to hear it's working for you.
I always use the same type of SD card—a 32GB SanDisk—for the 4-bit version.
It worked fine with the PIC32 and ESP32 WROOM.
I tried a different board—this time from SparkFun—and the card initialization caused problems there as well.
I checked the pins and they should be okay.

I think it's just a startup issue in my program?

[BenR]

The esp may have a different return value for the init. I may simply be ignoring it. Might be worth seeing if the other functions work ok and ill have a gander at the code to check the return values.

[stefan.erni]

Hi Ben

I tried to ignore the return value and create a file, but it didn't work.

[stefan.erni]

Hi Ben

It looks like the ESP32S3 has a lot of advantages.

For example, data sampling works directly in the interrupt macro,
and resetting the watchdog timer no longer requires a wait time of a few milliseconds.

Unfortunately, the SD card isn't working yet.