LOLIN S2 Mini

Development Board

Code name: LOLIN_S2_MINI

ESP32S2 WEMOS

LOLIN S2 Mini is a development board based on the ESP32S2 microcontroller using XTENSA architecture.

This board features a maximum CPU frequency of 240 MHz and 4MB flash memory.

About LOLIN S2 Mini

Compact ESP32-S2 board by Wemos with USB-C and LiPo charging - perfect for space-saving embedded builds.

Where to Buy LOLIN S2 Mini

Starting from

5$ per unit

Amazon.com Ships worldwide

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Amazon.de Ships to EU

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

Technical Specifications

Complete technical specification details for LOLIN S2 Mini

Connectivity

WiFi 802.11 b/g/n 2.4 GHz

Bluetooth -

BLE -

Microcontroller

Model esp32s2

Clock Speed 240 MHz

Flash Size 4MB

Architecture xtensa

✨ Features & Pins

Digital IO 48

Analog Input 20

PWM 24

Interrupts 46

Quick Setup

Copy-paste configs for LOLIN S2 Mini - auto‑generated from this board's exact hardware specs.

ESP32S2 240 MHz 4MB DIO Xtensa

In Arduino IDE 2 select Lolin S2 Mini from the esp32 by Espressif package. In PlatformIO use board = esp32-s2-saola-1. ESP32S2 · 240 MHz · 4MB · DIO.

Tools menu settings

Board (select in Arduino IDE) Lolin S2 Mini

CPU Frequency 240 MHz

Flash Size 4MB

Flash Mode DIO

Upload Speed 921600

Architecture Xtensa

In Arduino IDE 2, open Boards Manager, search "esp32" by Espressif and install it. Then go to Tools → Board and select "Lolin S2 Mini" for the LOLIN S2 Mini.

platformio.ini


[env:lolin_s2_mini]
platform  = espressif32
board     = esp32-s2-saola-1
framework = arduino

; Exact hardware config for LOLIN S2 Mini
board_build.mcu        = esp32s2
board_build.f_cpu      = 240000000L
board_build.flash_size = 4MB
board_build.flash_mode = dio
board_upload.flash_size = 4MB

The board value is a close generic match - check PlatformIO board registry for an exact fit.

esp32: block (YAML)


esp32:
  board: esp32-s2-saola-1
  framework:
    type: arduino   # or "esp-idf"

# LOLIN S2 Mini - 240 MHz ESP32S2
# Flash: 4MB | USB: N/A

Paste into your device's .yaml. See ESPHome ESP32 docs for full options.

esptool.py - flash command


esptool.py \
  --chip esp32s2 \
  --baud 921600 \
  write_flash \
    --flash_mode dio \
    --flash_size 4MB \
    0x1000 bootloader.bin \
    0x8000    partitions.bin \
    0xe000    boot_app0.bin \
    0x10000   firmware.bin

Install: pip install esptool - replace firmware.bin with your binary - bootloader at 0x1000

LOLIN S2 Mini Pinout Diagram

Complete pin reference for LOLIN S2 Mini

Safe Pins to Use

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

IO1

IO2

IO3

IO4

IO5

IO6

IO7

IO8

IO17

IO18

IO21

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
IO9	FSPIHD	Typically used as flash/PSRAM IO line in certain configurations; avoid using as GPIO if flash or PSRAM is present.	⚡ Flash
IO10	FSPICS0	Often used as flash chip select in some designs; not available for GPIO when controlling flash.	⚡ Flash
IO11	FSPID	Used for flash data transfer in certain configurations; should be avoided for general use if flash is connected.	⚡ Flash
IO12	FSPICLK	Used as flash clock line in some boards; not free for GPIO if driving flash.	⚡ Flash
IO13	FSPIQ	Used for flash data output in certain configurations; avoid using as GPIO if connected to flash.	⚡ Flash
IO14	FSPIWP	Used as flash write-protect/data line on some modules; not recommended for other usage.	⚡ Flash
IO15	XTAL_32K_P	If an external 32 kHz crystal is used for RTC, this pin is dedicated to the crystal and cannot be used as GPIO.	🪛 Other
IO16	XTAL_32K_N	If using an external 32 kHz crystal, this pin is connected to the crystal and should not be used as general I/O.	🪛 Other
IO33	SPIHD	Connected to SPI flash (hold/data line); not available for general-purpose use.	⚡ Flash
IO34	SPIWP	Connected to SPI flash (write-protect/data line); not recommended for other use.	⚡ Flash
IO35	FSPID	Used by internal flash/PSRAM on some ESP32-S2 variants; avoid using as GPIO to prevent conflicts.	⚡ Flash
IO36	FSPICLK	May be connected to internal flash or used for high-speed SPI; not intended for general GPIO use.	⚡ Flash
IO37	FSPIQ	Used for internal flash/PSRAM data in some models; should not be repurposed for GPIO.	⚡ Flash
IO38	FSPIWP	Reserved for flash/PSRAM in ESP32-S2 modules with internal memory; not recommended for general I/O.	⚡ Flash
IO39	MTCK	Used for JTAG debugging interface; using this pin for other purposes will disable JTAG clock input.	🪛 Other
IO40	MTDO	Part of JTAG interface (TDO); should be avoided as GPIO if JTAG debugging is needed.	🪛 Other

Useful Links

Datasheets and resources for LOLIN S2 Mini

ESP32S2 Datasheet

Microcontroller reference

LOLIN S2 Mini Custom Pin Mapping

Pin configuration and GPIO mapping for LOLIN S2 Mini

Digital I/O Pins

Interrupt Pins

Analog Inputs

PWM Pins

Pin	Function	ESP Pin	I/O Type	Description
1	5V	5V	POWER INPUT	5V power input for the board
2	GND	GND	POWER GROUNT	Ground connection
3	3V3	3.3V	POWER OUTPUT	3.3V power output
5	IO1	GPIO1	BIDIRECTIONAL	GPIO
6	IO2	GPIO2	BIDIRECTIONAL	GPIO, ADC
7	IO3	GPIO3	BIDIRECTIONAL	GPIO
8	IO4	GPIO4	BIDIRECTIONAL	GPIO, ADC
9	IO5	GPIO5	BIDIRECTIONAL	GPIO
10	IO6	GPIO5	BIDIRECTIONAL	GPIO
11	IO7	GPIO5	BIDIRECTIONAL	GPIO
12	IO8	GPIO5	BIDIRECTIONAL	GPIO
13	IO9	GPIO5	BIDIRECTIONAL	GPIO
14	IO10	GPIO5	BIDIRECTIONAL	GPIO
15	IO11	GPIO5	BIDIRECTIONAL	GPIO
16	IO12	GPIO12	BIDIRECTIONAL	GPIO, ADC
17	IO13	GPIO13	BIDIRECTIONAL	GPIO, ADC
18	IO14	GPIO14	BIDIRECTIONAL	GPIO, ADC
19	IO15	GPIO15	BIDIRECTIONAL	GPIO, ADC
20	IO16	GPIO16	BIDIRECTIONAL	GPIO
21	IO17	GPIO17	BIDIRECTIONAL	GPIO
22	IO18	GPIO18	BIDIRECTIONAL	GPIO
23	IO21	GPIO21	BIDIRECTIONAL	GPIO
24	IO33	GPIO33	BIDIRECTIONAL	GPIO, ADC
25	IO34	GPIO34	INPUT	GPIO, ADC
26	IO35	GPIO35	INPUT	GPIO, ADC
27	IO36	GPIO36	INPUT	GPIO, ADC
28	IO37	GPIO37	INPUT	GPIO, ADC
29	IO38	GPIO38	INPUT	GPIO, ADC
30	IO39	GPIO39	INPUT	GPIO, ADC
31	IO40	GPIO40	INPUT	GPIO, ADC

Legend

Function Pin role

GPIO ESP32 pin

I/O Direction

# Pin number

Pin Mappings

Complete pinout and GPIO mapping for LOLIN S2 Mini

Digital I/O Pins

Interrupt Pins

Analog Inputs

PWM Pins

Pin	Analog	Touch	PWM	Other
1	A0	T1	PWM
2	A1	T2	PWM
3	A2	T3	PWM
4	A3	T4	PWM
5	A4	T5	PWM
6	A5	T6	PWM
7	A6	T7	PWM	SCK
8	A7	T8	PWM
9	A8	T9	PWM	MISO
10	A9	T10	PWM
11	A10	T11	PWM	MOSI
12	A11	T12	PWM	SS
13	A12	T13	PWM
14	A13	T14	PWM
15	A14		PWM	LED_BUILTIN
16	A15		PWM
17	A16		PWM	DAC1
18	A17		PWM	DAC2
19	A18		PWM
20	A19		PWM
33			PWM	SDA
35			PWM	SCL
37			PWM	RX
39			PWM	TX
0x00000000				USB_FW_MSC_SERIAL_NUMBER

Legend

A0 Analog input

T0 Touch sensor

PWM PWM capable

RX/TX Serial pins

LED Built-in LED

# Pin number

Default Tools & Configuration

Build and upload settings for LOLIN S2 Mini

Setting	Value
Bootloader tool	esptool_py
Uploader tool	esptool_py
Network uploader tool	esp_ota
Bootloader address	`0x1000`
Flash mode	dio
Boot mode	qio
Maximum upload size	1280 KB (1310720 bytes)
Maximum data size	320 KB (327680 bytes)