ESP32 Forum

Posted: **Wed Jan 06, 2021 10:53 am**

Hi all,
First time poster here and have only had my ESP32 for 2 months now!

I am having issues getting my SD card reader to work. It works perfectly in my Arduino Uno, but I can't get it to work on my ESP. My wiring is as below (it is a 5v SD board):

SD Card - ESP32
CS - 5
SCK - 18
MOSI - 23
MISO - 19

When I load up on the Arduino IDE the Example 'SD-Files' it just says the below in the Serial output:
Initializing SD card...initialization done.
example.txt doesn't exist.
Creating example.txt...
example.txt doesn't exist.
Removing example.txt...
example.txt doesn't exist.

If I take out the SD card from the reader the Initialization fails, so I know that it can see the card, it just can't read or write to it. The SD card is 2GB and formatted as FAT. I have tried 3 different card readers and 4 different SD cards, all card readers and cards are readable by my Arduino Uno.

I tried loading the example 'CardInfo', but it errors on compile stating " 'Sd2Card' does not name a type".

Does anybody have any basic code that allows loading of a file and writing something to it?
I want to write a program that reads a text file for the SSID and password details which are stored on it, so it can then use them to connect to a wireless network.

Many thanks to all who reply to my post.

Alan

Posted: **Wed Jan 06, 2021 6:27 pm**

Some code might help!
I have used an SD card on ESP32 (using a hacked Ardunio driver) without issue - and I test hard.

My only 'quick win' thought is that you should wind SPI clock speed back to say 1 MHz and then work up.
ESP32 peripherals are slower than you might expect & GPIO muxing does not help.

Actually, a second thought is that Ardunio is often 5V and so is your card a 5V card??

Would be great for you to post in the bragging forum once done as AFAIK there is not a posted SD card driver (least not 18 months ago when I had this task).

Post if you resolve though, even if it was a solder joint!

Posted: **Wed Jan 06, 2021 8:57 pm**

Thank you @PeterR for your reply. Yes, it might have been helpful for me to post some code.

The ESP32 that I am using is "ESP32-WROOM-32D".

In answer to your question, the SD card reader is 5v, it has a AMS1117 voltage regulator and level shifter on the board. Below is a photo of it:

Then below is it wired up:

The test code that I am trying to use is:

Code: Select all

#include <SPI.h>
#include <SD.h>

File myFile;

void setup() {
  // Open serial communications and wait for port to open:
  Serial.begin(115200);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }


  Serial.print("Initializing SD card...");

  if (!SD.begin(5)) {
    Serial.println("initialization failed!");
    while (1);
  }
  Serial.println("initialization done.");

  if (SD.exists("example.txt")) {
    Serial.println("example.txt exists.");
  } else {
    Serial.println("example.txt doesn't exist.");
  }

  // open a new file and immediately close it:
  Serial.println("Creating example.txt...");
  myFile = SD.open("example.txt", FILE_WRITE);
  myFile.close();

  // Check to see if the file exists:
  if (SD.exists("example.txt")) {
    Serial.println("example.txt exists.");
  } else {
    Serial.println("example.txt doesn't exist.");
  }

  // delete the file:
  Serial.println("Removing example.txt...");
  SD.remove("example.txt");

  if (SD.exists("example.txt")) {
    Serial.println("example.txt exists.");
  } else {
    Serial.println("example.txt doesn't exist.");
  }
}

void loop() {
  // nothing happens after setup finishes.
}

The Serial Output is this:

Initializing SD card...initialization done.
example.txt doesn't exist.
Creating example.txt...
example.txt doesn't exist.
Removing example.txt...
example.txt doesn't exist.

Sadly since I am so new to this, I do not know how to lower the clock speed. I literally am downloading sample code to see if it works, how it works and trying to alter it to suit my needs.
I would be more than happy to write a post once I have it working so others can see it in the future.

If @PeterR you can offer any advice, it would be greatly taken. If though you think I would be better to use a different SD card reader, I am happy to buy different one if you can suggest one.

Many thanks
Alan

Posted: **Thu Jan 07, 2021 8:52 am**

Hi,

Why don't you try soldering some wires on a SD Card adaptor (SD to micro SD)? Since everything works on 3V3, you don't need the LDO and the level shifter.

This is not a proper solution but can give you a chance to test it.

Posted: **Thu Jan 07, 2021 9:55 am**

Hi @ ESP_Minatel
Thank you for your reply.
I'd be ok to try this, but can you point me to a web page that shows what pin goes where and some sample code.

Many thanks
Alan

Posted: **Thu Jan 07, 2021 10:52 am**

Hi,

You can follow this: SD Library

Posted: **Thu Jan 07, 2021 11:17 am**

Thank you very much @ESP_Minatel
I will give that a try later on today and will let you know how I go. I am going to order some of the below from a well known China distributor, so I can solder them directly to the PCBs I make. I will just need to work out their pin layouts once they arrive.

Again, thank you for your help.

Posted: **Thu Jan 07, 2021 5:52 pm**

This may be problem with sd card, esp32 can be picky about sd cards.

Posted: **Tue Jan 12, 2021 8:46 am**

ESP_Minatel wrote: ↑
Thu Jan 07, 2021 10:52 am
Hi,

You can follow this: SD Library

Thank you so much for your help ESP_Minatel. I took an old SD Card reader and soldered the wires directly to it. I was able then to access it and have made myself a basic Datalogger program.

That is a good point @chegewara, thank you.

Onto the next project now!

Cheers all

Posted: **Tue Jan 12, 2021 2:20 pm**

I had the same issue recently and the advice of ESP_Minatel helps me too, so use it

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