LilyGo T-Deck Development Board

Code name: LILYGO_T_DECK

LilyGo T-Deck 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.

⚡ Tech Specs 📌 Pinout 🔗 Useful Links 🗺️ Mappings 🛠️ Tools

About LilyGo T-Deck

🚀 The LilyGo T-Deck is a versatile development device featuring an ESP32-S3FN16R8 dual-core processor with integrated Wi-Fi and Bluetooth 5 (LE). It boasts a 2.8-inch IPS LCD (320x240) touch screen, a mini keyboard, and a trackball, making it ideal for portable applications. ⚡

📡 With support for LoRa transceiver (SX1262) at various frequencies (433/868/915 MHz), it enables long-range communication for IoT projects. The device comes with 16MB Flash and 8MB PSRAM, providing ample memory for complex applications.

💾 Additional features include a microphone, speaker, and optional GPS module, enhancing its functionality for diverse use cases.

Where to Buy LilyGo T-Deck

Starting from

$60 per unit

Amazon.de Ships to EU

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AliExpress Best value

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Prices are subject to change. We earn from qualifying purchases as an Amazon Associate.

LilyGo T-Deck Technical Specifications

🖥️ Display

Type IPS LCD

Size 2.8"

Resolution 320x240

Driver ST7789

🛰️ Connectivity

WiFi 802.11 b/g/n (2.4 GHz)

Bluetooth 5.0

BLE 5.0

Zigbee Yes

🧠 Microcontroller

Model esp32s3

Clock Speed 240 MHz

Flash Size 16MB

PSRAM Size 8MB

Architecture xtensa

✨ Features

48 digital IO pins
46 external interrupt pins
20 analog input pins
27 PWM pins

View Full Datasheet

LilyGo T-Deck Pinout

The LilyGo T-Deck pinout offers multiple GPIOs with various functionalities:

IO1 to IO3: GPIO, Touch, ADC

IO10 to IO13: SPI interface (CS, D, CLK, Q)

IO16: ADC

IO17 and IO18: UART (TX, RX)

IO38 to IO48: LCD data lines and control signals

Additionally, power pins like 3V3, 5V, and GND are available for peripheral connections.

✅ Safe Pins to Use

For general GPIO usage, these are the safest and most flexible choices:

🔹 IO1

🔹 IO2

🔹 IO16

🔹 IO17

🔹 IO18

🔹 IO21

🔹 IO5

🔹 IO6

🔹 IO7

🔹 IO8

🔹 IO15

🔹 IO4

🔹 IO22

🔹 IO23

🔹 IO24

🔹 IO25

🔹 IO26

🔹 IO27

🔹 IO28

🔹 IO29

🔹 IO30

🔹 IO31

🔹 IO32

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
IO38	FSPIWP	On flash-equipped chips, this pin is tied to the flash’s WP# (or D3) line. It should be avoided for other use, as it’s needed for flash operations.	⚡ Flash
IO39	MTCK (GPIO39)	Default JTAG debugging TCK pin. If JTAG is needed, this pin must be free; it may also be used internally for PSRAM chip select on certain modules, so avoid repurposing it.	🪛 Other
IO40	MTDO (GPIO40)	Default JTAG TDO output for debugging. Using it as GPIO will interfere with JTAG debugging functionality.	🪛 Other
IO41	MTDI (GPIO41)	Default JTAG TDI input for debugging. Should be reserved for JTAG or left unused if JTAG is to remain available.	🪛 Other
IO42	MTMS (GPIO42)	Default JTAG TMS signal for debugging. Using this pin for other purposes will disable the JTAG interface (unless JTAG is rerouted to USB).	🪛 Other
IO45	GPIO45	Determines flash/PSRAM power voltage (3.3 V vs 1.8 V) at boot. Must match hardware configuration; using as GPIO can upset flash supply setting.	🛠️ Strapping
IO46	GPIO46	Must be at a defined level during reset (with GPIO0) to select normal or download boot and UART/USB print mode. This pin is input-only (no output drive), so it should be left for its intended strapping function.	🛠️ Strapping
IO47	SPICLK_P	Used only on variants with Octal SPI interface (e.g. ESP32-S3R16V) as part of the differential clock pair. On such chips it operates at 1.8 V and is reserved for the high-speed octal SPI clock, not for general GPIO use.	⚡ Flash
IO48	SPICLK_N	Used only on variants with Octal SPI interface, as the negative leg of the differential clock&. On such chips it operates at 1.8 V; it should be avoided for GPIO to prevent conflicts with the octal flash/PSRAM clock.	⚡ Flash
IO9	FSPIHD	Connected to external flash (data/hold signal) on most modules. Not recommended for use as GPIO, since it must remain dedicated to flash communication.	⚡ Flash
IO14	FSPIWP	Connected to external flash (data/write-protect signal). Not recommended as GPIO because it’s reserved for flash operations.	⚡ Flash
IO20	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

LilyGo T-Deck Useful Links

🔗 Datasheet

https://lilygo.cc/products/t-deck

🔗 ESP32S3 Datasheet

https://www.espressif.com/sites/default/files/documentation/esp32-s3_datasheet_en.pdf

LilyGo T-Deck 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 for the board
4	IO1	GPIO1	BIDIRECTIONAL	GPIO, Touch, ADC
5	IO2	GPIO2	BIDIRECTIONAL	GPIO, Touch, ADC
6	IO3	GPIO3	BIDIRECTIONAL	GPIO, Touch, 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	ADC2_CH5	BIDIRECTIONAL	GPIO, ADC
12	IO17	U1_TXD	BIDIRECTIONAL	GPIO, UART TX
13	IO18	U1_RXD	BIDIRECTIONAL	GPIO, UART RX
14	IO21	GPIO21	BIDIRECTIONAL	GPIO
15	IO38	LCD_BL	OUTPUT	GPIO, LCD Backlight
16	IO39	LCD_D0	OUTPUT	GPIO, LCD Data 0
17	IO40	LCD_D1	OUTPUT	GPIO, LCD Data 1
18	IO41	LCD_D2	OUTPUT	GPIO, LCD Data 2
19	IO42	LCD_D3	OUTPUT	GPIO, LCD Data 3
20	IO45	LCD_D4	OUTPUT	GPIO, LCD Data 4
21	IO46	LCD_D5	OUTPUT	GPIO, LCD Data 5
22	IO47	LCD_D6	OUTPUT	GPIO, LCD Data 6
23	IO48	LCD_D7	OUTPUT	GPIO, LCD Data 7
24	IO5	LCD_RES	OUTPUT	GPIO, LCD Reset
25	IO6	LCD_CS	OUTPUT	GPIO, LCD Chip Select
26	IO7	LCD_DC	OUTPUT	GPIO, LCD Data/Command
27	IO8	LCD_WR	OUTPUT	GPIO, LCD Write
28	IO9	LCD_RD	OUTPUT	GPIO, LCD Read
29	IO15	LCD_POWER_ON	OUTPUT	GPIO, LCD Power Enable
30	IO4	LCD_BAT_VOLT	INPUT	GPIO, Battery Voltage Sense
31	IO14	BUTTON	INPUT	User Button
32	IO20	MIC	INPUT	Microphone Input
33	IO22	SPEAKER	OUTPUT	Speaker Output
34	IO23	LOADER	OUTPUT	Flash Loader
35	IO24	KEYBOARD	INPUT	Keyboard Input
36	IO25	TRACKBALL	INPUT	Trackball Sensor
37	IO26	GPS_RX	INPUT	GPS Module RX
38	IO27	GPS_TX	OUTPUT	GPS Module TX
39	IO28	LORA_CS	OUTPUT	LoRa Chip Select
40	IO29	LORA_RST	OUTPUT	LoRa Reset
41	IO30	LORA_IRQ	INPUT	LoRa Interrupt Request
42	IO31	EXPANSION	BIDIRECTIONAL	Expansion GPIO
43	IO32	EXTRA	BIDIRECTIONAL	Extra GPIO

Function Pin Function

ESP Pin Pin on ESP32

I/O Input/Output Pin

Description Pin Description

LilyGo T-Deck Pins Mapping Arduino IDE

Below you can find the LilyGo T-Deck pinout. 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	Analog	Touch	PWM	Other
0				BUTTON_1
1	A0	T1	PWM
2	A1	T2	PWM
3	A2	T3	PWM
4			PWM	BAT_VOLT
10	A9	T10	PWM	SS
11	A10	T11	PWM	MOSI
12	A11	T12	PWM	SCK
13	A12	T13	PWM	MISO
17	A16		PWM	SCL
18	A17		PWM	SDA
43			PWM	TX
44			PWM	RX

Analog Analog input pins

Touch Touch pins

Function Function pins

RX / TX Receive/Transmit

LED_BUILTIN Built-in LED

PWM Pulse-Width Modulation

Default Tools for LilyGo T-Deck

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 T-Deck 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 T-Deck 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).