Lilygo T5 S3 SD Card Issues: Troubleshooting And Solutions

Aug 12, 2025 by Pedro Alvarez 59 views

Troubleshooting SD Card Read Issues on Lilygo T5 S3 with EPD 4.7

Hey everyone! Having some trouble with the SD card reader on my Lilygo T5 S3 with EPD 4.7, and I figured I'd share what I've tried and see if anyone has some insights. Let's dive into the details and get this sorted out!

The Problem: No SD Card Reading

So, here's the deal: I'm trying to read a simple text file from a 16 GB FAT32 SD card using my Lilygo T5 S3 with the EPD 4.7 display. I've whipped up some Arduino code to test the SD card functionality, but I'm not getting any data back. It's like the SD card is a ghost – there, but not really interacting. I've been scratching my head over this for a bit, and now I'm reaching out to the community for some help. Maybe someone has run into this before or has a brilliant idea I haven't thought of yet. Let's troubleshoot this together and get my Lilygo T5 S3 reading those files!

Initial Setup and Code

To give you a clear picture, here’s what I’ve set up. I’m using a 16 GB SD card formatted as FAT32, which should be compatible with the Lilygo T5 S3. I’ve connected the SD card module to the Lilygo T5 S3, and I’m using the SPI interface to communicate with it. The connections should be straightforward, but maybe I've made a mistake somewhere. I'm not ruling anything out at this stage. I've included my initial test code below, which is designed to initialize the SPI bus and send a test byte to the SD card. The goal is to see if I can get any response back, indicating that the SPI communication is working. If the SPI communication isn't working, then reading files from the SD card is going to be impossible. Let's take a look at the code:

#include <SPI.h>
// Define the pins
#define CS_PIN 42
#define SCK_PIN 11
#define MOSI_PIN 15
#define MISO_PIN 16

void setup() {
  Serial.begin(115200);
  while (!Serial); // Wait for the serial port to connect

  // Initialize SPI bus
  SPI.begin(SCK_PIN, MISO_PIN, MOSI_PIN, CS_PIN);
  pinMode(CS_PIN, OUTPUT);
  digitalWrite(CS_PIN, HIGH); // Deselect the slave initially

  Serial.println("SPI Initialized");
}

void loop() {
  // Test SPI communication
  digitalWrite(CS_PIN, LOW); // Select the slave

  // Send a test byte
  byte testByte = 0x55; // Example byte to send
  byte receivedByte = SPI.transfer(testByte);

  digitalWrite(CS_PIN, HIGH); // Deselect the slave

  Serial.print("Sent: 0x");
  Serial.print(testByte, HEX);
  Serial.print(", Received: 0x");
  Serial.println(receivedByte, HEX);

  delay(1000); // Wait for a second before repeating
}

This code initializes the SPI interface and then sends a test byte (0x55) to the SD card in a loop. It then prints the sent and received bytes to the serial monitor. The problem is that I'm not receiving any byte back from the SPI. This suggests that there's an issue with the SPI communication itself, or perhaps the SD card isn't responding correctly. I'm hoping that by sharing this code, someone might spot an obvious mistake or suggest a better way to test the SPI communication. It's always helpful to have another set of eyes on the problem!

The Core Issue: No SPI Response

The main problem I'm facing is that I'm not getting any response from the SD card when I try to communicate over SPI. My test code sends a byte, but the received byte is always 0x00, indicating that there's no data coming back. This is a major roadblock because without successful SPI communication, I can't read any files from the SD card. It's like trying to have a conversation with someone who isn't listening! This could be due to a variety of reasons, such as incorrect pin assignments, a faulty SD card module, or even a software issue. The first thing I did was double-check my wiring, making sure that each pin is connected to the correct place on the Lilygo T5 S3. Then, I tried a different SD card to rule out the possibility of a faulty card. But so far, nothing has worked. I'm starting to wonder if the issue might be with the SPI configuration or some other low-level setting that I'm not aware of. That's why I'm turning to the community – maybe someone has encountered this specific issue before and knows a trick or two to get it working.

Pin Configuration Concerns

One of my primary concerns is whether the pin definitions in my code are correct for the Lilygo T5 S3. I've defined the CS_PIN as 42, SCK_PIN as 11, MOSI_PIN as 15, and MISO_PIN as 16. However, I haven't been able to find definitive documentation that confirms these are the correct pins for the SD card interface on this particular board. This is like trying to find your way in a dark room without a map! If these pins are incorrect, then the SPI communication would obviously fail. The datasheet for the Lilygo T5 S3 might have this information, but I haven't been able to locate it yet. If anyone has a pinout diagram or knows the correct pins for the SD card interface, that would be a huge help. It's also possible that the pins are multiplexed with other functions, and I need to configure them correctly in the code. This is another area where I could use some guidance. Making sure the pins are correctly configured is the first step to getting the SD card reader working, and I'm hoping this is the key to solving my problem.

Seeking a Working Example

To move forward, I'm really hoping someone can share a working Arduino code example that demonstrates how to read a simple text file from the SD card on the Lilygo T5 S3. Seeing a fully functional example would be like having a lighthouse to guide my ship! It would allow me to compare my code and setup with a known working configuration, and identify any discrepancies. A basic example that initializes the SD card, opens a text file, reads its contents, and prints them to the serial monitor would be perfect. This would not only help me troubleshoot my current issue but also give me a solid foundation for future projects involving SD card access. If you've successfully read files from an SD card on the Lilygo T5 S3, please consider sharing your code – it would be immensely helpful!

Troubleshooting Steps Taken

So far, I've tried a few things to troubleshoot this issue, but no luck yet. It feels like I'm chasing a ghost in the machine! First, I double-checked all the wiring to make sure everything is connected correctly. Misplaced wires are a common culprit, so it's always good to start there. I also tried using a different SD card to rule out the possibility of a faulty card. Sometimes, the simplest solutions are the ones we overlook. I also reviewed my code multiple times, looking for any obvious errors or omissions. It's easy to miss a small mistake, especially when you've been staring at the code for hours. Additionally, I've been searching online forums and documentation for any clues related to SD card issues on the Lilygo T5 S3. The internet is a vast resource, but sometimes it's hard to find the specific information you need. Despite these efforts, I'm still stuck, which is why I'm reaching out to the community for help. Sharing my experience and getting fresh perspectives is often the key to unlocking a solution.

Next Steps and Community Input

So, what are the next steps? I think the most crucial thing right now is to confirm the correct pin assignments for the SD card interface on the Lilygo T5 S3. If anyone has this information, please share! A working code example would also be incredibly helpful. In the meantime, I'm going to continue digging through documentation and online resources. I'm also planning to try a few more things, such as using a different SD card library or trying a different SPI speed. I'm determined to get this working, and I'm confident that with the help of the community, we can figure it out! If you have any suggestions, insights, or questions, please feel free to chime in. Let's get this SD card reader up and running!