Ronald Keus asked 4 years ago
Dear Sara, Rui, first of all: your book Learn ESP32 with Arduino IDE is perfect. Everything works immediately and as promised. I’ve by now tested many programs and they are all OK.
However, I have a quite trivial problem with writing to an SD-card. I’m using two identical SD-card modules exactly like the ones you use in one of the programs on your web-site: the small 3,3V-ones. And I’m using 4 different (two different brands) ESP32 Devkit V1 in combination wih two different 32MB HC-1 microSD-cards. When I use your program in the library SD(esp32) SD-test, in each and every combination of my ESP32’s and SD card modules, in about 30% of the runs I get the message “card mount failed”. My question now is:
1) any idea why this is the case?
2) woud using the SD_MMC library and “configuration” (whatever that is) solve the problem?
3) could the size of the microSD-cards; 32MB HC-1, cause the problem?
4) most important: since your proram in the library “SD(esp32) SD-test” is quite complicated, is there a program for the combination ESP32/SD-card that simply writes and reads data without further stuff, like the ones that exist for the Arduino?
Thanks in advance for your reply, Ronald Keus
Sara Santos Staff answered 4 years ago
Hi Ron.
To be honest, I’m not sure why you get the “card mount failed” sometimes. I don’t think the SD_MMC library configuration will make a different. Please note that if you want to use SD_MMC, your microSD card module must support SD_MMC (the modules we use don’t have SD_MMC support). There are other microSD card modules that support SD_MMC.
As for the microSD card, they must be formatted as FAT32.
We have this tutorial about the microSD card with the ESP32 (this is probably the example you’ve already tested): https://randomnerdtutorials.com/esp32-microsd-card-arduino/#handlefilesmicrosdcard
Regards,
Sara