LilyGo T-Dongle S3

Development Board

Code name: LILYGO_T_DONGLE_S3

LilyGo T-Dongle S3 is a development board based on the ESP32S3 microcontroller using XTENSA architecture.

This board features a maximum CPU frequency of 240 MHz and 16MB flash memory.

About LilyGo T-Dongle S3

🚀 The LilyGo T-Dongle S3 is a compact development board featuring an ESP32-S3 processor with integrated WiFi and Bluetooth 5. It is designed as a USB-powered dongle for easy plug-and-play development. ⚡

📡 The T-Dongle S3 is equipped with 8MB PSRAM and 16MB Flash, providing ample memory for IoT and embedded applications.

💾 With multiple GPIOs, ADC, PWM, I2C, and SPI support, this board is ideal for prototyping and rapid development.

📋 Technical Specifications

Complete technical specification details for LilyGo T-Dongle S3

🖥️ Display

Type LCD

Size 0.96"

Resolution 80x160

Driver ST7735

🛰️ Connectivity

WiFi 802.11 b/g/n (2.4 GHz)

Bluetooth 5.0

BLE 5.0

🧠 Microcontroller

Model esp32s3

Clock Speed 240 MHz

Flash Size 16MB

Architecture xtensa

✨ Features & Pins

Digital IO 21

Analog Input 6

PWM 14

Interrupts 46

Download Full Datasheet

LilyGo T-Dongle S3 Pinout Diagram

Complete pin reference for LilyGo T-Dongle S3

✅ Safe Pins to Use

These pins are safe for general GPIO usage without boot or system conflicts

IO1

IO2

IO16

IO17

IO18

IO21

IO22

IO23

💡 Why Are These Pins Safe?

✓ No boot sequence involvement

✓ No flash/PSRAM connections

✓ No USB or JTAG conflicts

✓ Freely assignable without issues

⚠️ Pins to Avoid or Use with Caution

Reserved for critical functions. Misuse may cause boot failures, programming issues, or system conflicts.

🔄 Strapping Pins

Boot behavior & flash voltage

🐛 JTAG Debugging

Low-level debugging interface

🔌 USB Pins

USB Serial/JTAG communication

💾 Flash/SPI Pins

Memory & PSRAM connections

📡 UART Serial

Debugging & firmware uploads

PIN	Label	Why Avoid	Type
IO3	GPIO3	Sampled at reset to select JTAG interface (USB Serial/JTAG controller vs. external pins). Improper use can disable external JTAG or alter debug interface.	🛠️ Strapping
IO19	USB_D-	By default connected to the on-chip USB Serial/JTAG controller. Using it as general GPIO without reconfiguring IO MUX will interfere with USB functionality.	🔌 USB

Useful Links

Datasheets and resources for LilyGo T-Dongle S3

Board Datasheet

Technical specifications

ESP32S3 Datasheet

Microcontroller reference

LilyGo T-Dongle S3 Custom Pin Mapping

Pin configuration and GPIO mapping for LilyGo T-Dongle S3

Digital I/O Pins

Interrupt Pins

Analog Inputs

PWM Pins

Pin	Function	ESP Pin	I/O Type	Description
1	3V3	3.3V	POWER OUTPUT	3.3V power output
2	GND	GND	POWER GROUND	Ground connection
3	5V	5V	POWER INPUT	5V power input
4	IO1	GPIO1	BIDIRECTIONAL	GPIO, ADC, I2C
5	IO2	GPIO2	BIDIRECTIONAL	GPIO, ADC
6	IO3	GPIO3	BIDIRECTIONAL	GPIO, ADC
7	IO16	SPI_CS	BIDIRECTIONAL	GPIO, SPI Chip Select
8	IO17	SPI_D	BIDIRECTIONAL	GPIO, SPI Data
9	IO18	SPI_CLK	BIDIRECTIONAL	GPIO, SPI Clock
10	IO19	SPI_Q	BIDIRECTIONAL	GPIO, SPI Q
11	IO21	USB_D+	BIDIRECTIONAL	GPIO, USB Data+
12	IO22	USB_D-	BIDIRECTIONAL	GPIO, USB Data-
13	IO23	RGB_LED	OUTPUT	GPIO, Addressable RGB LED

Legend

Function Pin role

GPIO ESP32 pin

I/O Direction

# Pin number

Default Tools & Configuration

Build and upload settings for LilyGo T-Dongle S3

Setting	Value
Bootloader tool	esptool_py
Uploader tool	esptool_py
Network uploader tool	esp_ota
Bootloader address	`0x0`
Flash mode	dio
Boot mode	qio
PSRAM type	opi
Maximum upload size	3072 KB (3145728 bytes)
Maximum data size	320 KB (327680 bytes)