LilyGo T3S3 V1.0 Development Board
Code name: LILYGO_T3S3_V1_0
LilyGo T3S3 V1.0 development board is based on esp32s3 microcontroller and uses xtensa architecture. This board has a maximum CPU frequency of 240 MHz and a flash size of 16MB.
About LilyGo T3S3 V1.0
🚀 The LilyGo T3S3 V1.0 is an ESP32-S3-based development board designed for high-performance applications. With integrated WiFi and Bluetooth 5, it offers seamless wireless connectivity for IoT projects. ⚡
📡 Featuring a compact design, the T3S3 V1.0 is equipped with 8MB PSRAM and 16MB Flash, ensuring sufficient storage and processing power for complex tasks.
💾 The board includes multiple GPIOs, ADC, PWM, I2C, and SPI support, making it suitable for a wide range of embedded applications.
LilyGo T3S3 V1.0 Technical Specifications
🖥️ Display
🛰️ Connectivity
🧠 Microcontroller
✨ Features
- 48 digital IO pins
- 46 external interrupt pins
- 20 analog input pins
- 27 PWM pins
LilyGo T3S3 V1.0 Pinout
✅ Safe Pins to Use
For general GPIO usage, these are the safest and most flexible choices:
Why Are These Pins Safe?
- Not involved in bootstrapping → No impact on device boot mode or system startup
- Not linked to flash memory or PSRAM → Won't interfere with storage or memory access
- Not dedicated to USB or JTAG → Free for general use without affecting debugging
- No special hardware connections → Freely assignable without internal conflicts
⚠️ Pins to Avoid or Use with Caution
Some pins are reserved for critical functions like bootstrapping, JTAG debugging, USB communication, and flash memory operations. Misusing these pins may lead to boot failures, programming issues, USB conflicts, or disruptions in flash storage.
Critical Pin Categories:
- 🛠️ Strapping Pins: Control boot behavior and flash voltage selection
- 🔗 JTAG Debugging Pins: Required for low-level debugging
- 🔌 USB Communication Pins: Used for USB Serial/JTAG communication
- ⚡ Flash Memory & SPI Pins: Connected to SPI flash memory and PSRAM
- 📡 UART Serial Communication Pins: Used for debugging and firmware uploads
| PIN | Label | Reason | Function |
|---|---|---|---|
| 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 |
| IO10 | FSPICS0 | Used to select the external flash chip. It is required for flash access and cannot be repurposed without losing flash connectivity | ⚡ Flash |
| IO11 | FSPID | Used as a data line for flash (and in-package PSRAM). It should not be used as GPIO when the flash/PSRAM is in use. | ⚡ Flash |
| IO12 | FSPICLK | Drives the flash (and PSRAM) clock. This critical signal must be reserved for memory and not used as general GPIO. | ⚡ Flash |
| IO13 | FSPIQ | Used as a data line for flash/PSRAM transfers. Not available for other uses when flash/PSRAM is connected. | ⚡ Flash |
LilyGo T3S3 V1.0 Pin Mappings
This development board provides 48 digital IO pins, out of which 46 can be used as external interrupt pins , 20 as analog input pins and 27 pins have Pulse-Width Modulation (PWM) .
| Pin | Function | ESP Pin | Input/Output | 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 | IO10 | SPI_CS | BIDIRECTIONAL | GPIO, SPI Chip Select |
| 8 | IO11 | SPI_D | BIDIRECTIONAL | GPIO, SPI Data |
| 9 | IO12 | SPI_CLK | BIDIRECTIONAL | GPIO, SPI Clock |
| 10 | IO13 | SPI_Q | BIDIRECTIONAL | GPIO, SPI Q |
| 11 | IO16 | I2C_SCL | BIDIRECTIONAL | GPIO, I2C Clock |
| 12 | IO17 | I2C_SDA | BIDIRECTIONAL | GPIO, I2C Data |
| 13 | IO18 | UART_TX | BIDIRECTIONAL | GPIO, UART TX |
| 14 | IO19 | UART_RX | BIDIRECTIONAL | GPIO, UART RX |
Default Tools for LilyGo T3S3 V1.0
| 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 B) |
| Maximum data size | 320 Kb (327680 B) |
The LilyGo T3S3 V1.0 development board by default uses esptool_py uploader tool, esp_ota network uploader tool for Over-the-air (OTA) uploads and esptool_py bootloader tool. The bootloader starts at address "0x0". Flash mode and boot mode for LilyGo T3S3 V1.0 development board by default is dio and qio respectively. The board uses opi PSRAM type. When using Arduino IDE, the maximum sketch upload size is 3072 Kb (3145728 B) and maximum data size for variables is 320 Kb (327680 B).
