MicroSD / TF Module Test (ESP32)

A simple test project for reading and writing data to a MicroSD (TF) card module using the SPI interface with ESP32.

Hardware

Wiring

MicroSD Module	ESP32
CS	GPIO 5
SCK	GPIO 18
MISO	GPIO 19
MOSI	GPIO 23
VCC	5V
GND	GND

This module was tested successfully with a 5V power supply. 3.3V power did not work with this specific module.

Dependencies

No external library is required.

The project uses built-in Arduino libraries:

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

SPI Configuration

Custom SPI pins are configured as:

SPI.begin(18, 19, 23, CS);

Parameters:

SPI Signal	GPIO
SCK	18
MISO	19
MOSI	23
CS	5

SD Card Initialization

The SD card is initialized with a custom SPI instance:

SD.begin(CS, SPI, 1000000)

SPI frequency is set to:

1 MHz

Test Functionality

The test performs:

1. Initialize SD card.
2. Create/open /test.txt.
3. Write sample sensor log data.
4. Close the file.

Example output file:

2026/10/02 20:08 - Temp: 27.77 - Hum: 33.12%
2026/10/02 20:13 - Temp: 27.75 - Hum: 33.10%
2026/10/02 20:18 - Temp: 27.72 - Hum: 33.08%

Serial Output

Successful run:

SD OK!
Write OK!

If initialization fails:

SD Failed!

Notes

• MicroSD modules may require 5V power depending on their onboard regulator and level shifter.
• FAT32 formatted cards are recommended.
• For sensor logging projects, this module can be used as a simple data logger for temperature, humidity, and other measurements.