ESP32 Boards/ ESP32-S3 /Supermini

ESP32-S3 Super Mini

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Compact ESP32-S3 board with Wi-Fi, BLE, and AI support - great for smart, space-saving IoT and edge AI applications.

Popular USB-C Native USB

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22.52 × 18 mm

ESP32-S3

MCU

240MHz

clock

4MB

flash

512KB

SRAM

32· 16 ADC

GPIO

BLE 5.0+ WiFi

radio

Pinout

37 pins · 2.54 mm pitch

View:

Pin	GPIO	Labels	Status	Capabilities	Notes
1	-	5V	power	-	5V power input for the board
2	-	GND	ground	-	Ground connection
3	-	3V33.3V	power	-	3.3V power output for peripherals
4	-	TX	uart	uart	TX
5	-	RX	uart	uart	RX
6	1	IO1GP1	safe	adc	GPIO, ADC Pin
7	2	IO2GP2	safe	adc	GPIO, ADC pin
8	3	IO3GP3	strapping	adc	GPIO, ADC pin
9	4	IO4GP4	safe	adc	GPIO, ADC pin
10	5	IO5GP5	safe	adc	GPIO, ADC pin
11	6	IO6GP6	safe	adc	GPIO, ADC pin
12	7	IO7GP7	safe	adc	GPIO, ADC pin
13	8	IO8GP8	safe	adc	GPIO, ADC pin
14	9	IO9GP9	strapping	adc	GPIO, ADC pin
15	10	IO10GP10	strapping	adc	GPIO, ADC pin
16	11	IO11GP11	strapping	adc	GPIO, ADC pin
17	12	IO12GP12	strapping	adc	GPIO, ADC pin
18	13	IO13GP13	strapping	adc	GPIO, ADC pin
19	14	IO14GP14	strapping	adc	GPIO, ADC pin
20	15	IO15GP15	safe	adc	GPIO, ADC pin
21	16	IO16GP16	safe	adc	GPIO, ADC pin
22	17	IO17GP17	safe	-	GPIO
23	18	IO18GP18	safe	-	GPIO
24	21	IO21GP21	safe	-	GPIO
25	33	IO33GP33	strapping	-	GPIO
26	34	IO34GP34	strapping	-	GPIO
27	35	IO35GP35	strapping	-	GPIO
28	36	IO36GP36	strapping	-	GPIO
29	37	IO37GP37	strapping	-	GPIO
30	38	IO38GP38	strapping	-	GPIO
31	39	IO39GP39	strapping	-	GPIO
32	40	IO40GP40	strapping	-	GPIO
33	41	IO41GP41	strapping	-	GPIO
34	45	IO45GP45	strapping	-	GPIO
35	46	IO46GP46	strapping	-	GPIO
36	47	IO47GP47	strapping	-	GPIO
37	48	IO48GP48	strapping	-	GPIO

Start with these

12 pins with no boot or system involvement

IO1GP1IO2GP2IO4GP4IO5GP5IO6GP6IO7GP7IO8GP8IO15GP15IO16GP16IO17GP17IO18GP18IO21GP21

Freely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.

Fine - with a little care

sampled at boot or shared with debug/serial

Pin	Label	What to know	Role
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
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
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

Only if you know the tricks

wired to flash or USB - expect a fight

Pin	Label	What to know	Role
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
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
IO14	FSPIWP	Connected to external flash (data/write-protect signal). Not recommended as GPIO because it’s reserved for flash operations.	Flash
IO33	FSPIHD	On chips/modules with integrated flash, this IO is wired to the flash hold pin internally. It cannot be reassigned to GPIO without breaking flash access.	Flash
IO34	FSPICS0	Wired to the chip select of the internal flash in flash-equipped variants. It must remain low during flash operation, so it’s not available for other use.	Flash
IO35	FSPID / PSRAM_D0	In modules with octal PSRAM, this pin is connected to the PSRAM data line. It is reserved for memory interface and not free for general GPIO when flash/PSRAM is present.	Flash
IO36	FSPICLK / PSRAM_CLK	In modules with octal PSRAM, this pin drives the PSRAM clock. It must be dedicated to the memory interface, not used as a regular GPIO when that interface is in use.	Flash
IO37	FSPIQ / PSRAM_DQS	In modules with octal PSRAM, this pin is connected to the PSRAM’s DQS signal. It cannot be repurposed without disrupting the PSRAM/flash communication.	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
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

These are recommendations, not hard rules - with the right pull-ups, timing and boot-state awareness most pins can be made to work. When in doubt, start green.

Pinout notes Across 37 pins (2.54 mm pitch), the ESP32-S3 Super Mini exposes 32 GPIO plus 5V , GND and 3V3 for power. On the analog side there are 16 ADC-capable pins for…

Across 37 pins (2.54 mm pitch), the ESP32-S3 Super Mini exposes 32 GPIO plus 5V, GND and 3V3 for power.

On the analog side there are 16 ADC-capable pins for sensors and battery monitoring.

If you want zero surprises, IO1, IO2, IO4, IO5 and 8 more are free of any such role - the safest first picks. 6 of the exposed pins carry boot-time or system duties on the ESP32-S3 (IO3, IO39, IO40 and 3 more).

The ESP32-S3 Super Mini pinout is designed for maximum functionality in a compact package. The board provides essential power pins like 5V, 3.3V, and GND for stable power delivery.

It includes communication interfaces such as RX and TX for UART, SDA and SCL for I2C, and MISO, MOSI, SCK, and SS for SPI, ensuring seamless integration with peripherals.

For analog input, the ESP32-S3 Super Mini offers ADC pins labeled A0 to A5, making it suitable for sensor data acquisition. Additionally, it features an onboard WS2812 RGB LED, which allows programmable multi-color status indications for enhanced user feedback.

Guides & tutorials

Comparison ESP32 Super Mini boards compared C3 vs C3 Plus vs C6 vs S3 - which tiny board fits your project. 8 min read→

Getting started

flash your first firmware in ~2 minutes

Tool:

Connect over USB

Native USB - no driver, no serial chip. Not detected? Hold BOOT while plugging in.

Flash with your tool

Arduino IDE, PlatformIO, ESPHome or esptool - copy the settings on the right.

Verify it runs

The blink example uses GPIO1 - swap for your board's LED pin if different.

Tools → Board settings Copy

Board:            Esp32s3 Dev
USB CDC On Boot:  Enabled
Flash Size:       4MB · QIO
Upload Speed:     921600

// blink
pinMode(1, OUTPUT);
digitalWrite(1, LOW);   // on (often inverted)

platformio.ini Copy

[env:esp32-s3-super-mini]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600

device.yaml Copy

esp32:
  board: esp32-s3-devkitc-1
  variant: esp32s3
  framework:
    type: esp-idf

# blink - GPIO1
output:
  - platform: gpio
    pin: 1
    id: led_out
light:
  - platform: binary
    name: "LED"
    output: led_out

shell Copy

esptool.py --chip esp32s3 --port /dev/ttyACM0 \
  write_flash 0x0 firmware.bin

Build details: sketch space 1310720 B · data 327680 B · QIO

Good to know

board-specific quirks worth 60 seconds

Some units ship with the antenna soldered backwards

The S3 SuperMini inherits the C3 SuperMini's weak-antenna reputation - and on the S3 it can be worse. Multiple owners report units where the ceramic antenna is mounted the wrong way round : the PCB feed trace runs to the antenna's unconnected mounting pad, so the antenna element isn't electrically connected at all. The feed point sits on the side of the antenna marked with a white bar - on affected boards that side…

The S3 SuperMini inherits the C3 SuperMini's weak-antenna reputation - and on the S3 it can be worse. Multiple owners report units where the ceramic antenna is mounted the wrong way round: the PCB feed trace runs to the antenna's unconnected mounting pad, so the antenna element isn't electrically connected at all. The feed point sits on the side of the antenna marked with a white bar - on affected boards that side faces away from the feed trace.

If your board's WiFi range is unusually bad, check the antenna orientation before blaming the chip. Since these boards come from many unnamed factories, your unit may be fine - it varies batch to batch.

The same 31 mm quarter-wave wire mod that fixes the C3 SuperMini works here too - owners in the Hackaday discussion report it helps even more on the S3, precisely because the stock antenna often isn't connected in the first place.

It has 2 MB PSRAM - but it's off by default

Most S3 SuperMinis are built on the ESP32-S3FH4R2 - the board's user manual names that exact variant, and per Espressif's ESP32-S3 datasheet the "R2" suffix means 2 MB quad-SPI PSRAM packaged inside the chip , alongside 4 MB flash. Sellers rarely mention the PSRAM, and the default Arduino board profile ( ESP32S3 Dev Module ) leaves it disabled - so it's easy to own this board and never know it's there:…

Most S3 SuperMinis are built on the ESP32-S3FH4R2 - the board's user manual names that exact variant, and per Espressif's ESP32-S3 datasheet the "R2" suffix means 2 MB quad-SPI PSRAM packaged inside the chip, alongside 4 MB flash. Sellers rarely mention the PSRAM, and the default Arduino board profile (ESP32S3 Dev Module) leaves it disabled - so it's easy to own this board and never know it's there: ESP.getPsramSize() returns 0 until you enable it.

To use it: in Arduino IDE set Tools → PSRAM → "QSPI PSRAM" (not OPI - that's for octal chips and will crash). In ESPHome, add psram: with mode: quad. In PlatformIO, use board_build.arduino.memory_type = qio_qspi with -DBOARD_HAS_PSRAM.

These boards come from many factories, so verify what you actually got: check the chip marking (should read ESP32-S3FH4R2) or call ESP.getPsramSize() after enabling PSRAM.

No USB-serial chip - Serial needs USB CDC

Unlike classic ESP32 dev boards, the S3 SuperMini has no USB-to-serial converter chip - the USB-C port connects straight to the ESP32-S3's native USB. That keeps the board small, but it changes two everyday things: Serial output: enable Tools → USB CDC On Boot → "Enabled" in Arduino IDE, or Serial.print() goes to the (unpopulated) UART pins instead of your serial monitor. Flashing: uploads normally just work, but if…

Unlike classic ESP32 dev boards, the S3 SuperMini has no USB-to-serial converter chip - the USB-C port connects straight to the ESP32-S3's native USB. That keeps the board small, but it changes two everyday things:

Serial output: enable Tools → USB CDC On Boot → "Enabled" in Arduino IDE, or Serial.print() goes to the (unpopulated) UART pins instead of your serial monitor.
Flashing: uploads normally just work, but if the COM port never appears or an upload fails mid-way, hold BOOT while plugging in USB (or while tapping RESET) to force the ROM bootloader, then press RESET after flashing to start your sketch.

A crashed or deep-sleeping sketch takes the USB port down with it - that's normal for native-USB boards, not a broken board. The BOOT-button trick above always recovers it.

On-Board LEDs

The ESP32-S3 Supermini features multiple onboard LEDs, each mapped to specific GPIO pins. Below is a breakdown of their functions, pin assignments, and how to use them in both Arduino and ESPHome. Red LED – Power Indicator GPIO: GPIO48 Control: digitalWrite() Both the Red LED and WS2812 share GPIO48 and use different signal types (digital vs. timing-based), but due to the board’s fixed hardware design,…

The ESP32-S3 Supermini features multiple onboard LEDs, each mapped to specific GPIO pins. Below is a breakdown of their functions, pin assignments, and how to use them in both Arduino and ESPHome.

Red LED – Power Indicator

GPIO: GPIO48
Control: digitalWrite()
Both the Red LED and WS2812 share GPIO48 and use different signal types (digital vs. timing-based), but due to the board’s fixed hardware design, they cannot be used independently - any signal sent to GPIO48 will affect both, potentially causing flickering or unexpected behavior.

Arduino Example:


void setup() {
  pinMode(48, OUTPUT);
}

void loop() {
  digitalWrite(48, HIGH);
  delay(1000);
  digitalWrite(48, LOW);
  delay(1000);
}

ESPHome Example:


output:
  - platform: gpio
    pin: 48
    id: red_led

light:
  - platform: binary
    name: "Red LED"
    output: red_led

ESPHome GPIO Output Documentation →

Blue LED – Battery Charge Indicator

GPIO: None
Control: None
Behavior:

Charging → LED on
Battery connected → LED off
No battery → LED blinks

WS2812 LED – Programmable RGB

GPIO: GPIO48
Control: FastLED, NeoPixel, etc.
Both the Red LED and WS2812 share GPIO48 and use different signal types (digital vs. timing-based), but due to the board’s fixed hardware design, they cannot be used independently - any signal sent to GPIO48 will affect both, potentially causing flickering or unexpected behavior.

Arduino (FastLED) Example:

#include <FastLED.h>

#define NUM_LEDS 1
#define DATA_PIN 48

CRGB leds[NUM_LEDS];

void setup() {
  FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
}

void loop() {
  leds[0] = CRGB::Red; FastLED.show(); delay(1000);
  leds[0] = CRGB::Green; FastLED.show(); delay(1000);
  leds[0] = CRGB::Blue; FastLED.show(); delay(1000);
}

ESPHome (NeoPixelBus) Example:

light:
  - platform: neopixelbus
    type: GRB
    pin: 48
    num_leds: 1
    name: "Onboard RGB LED"

ESPHome NeopixelBus Documentation →

Specifications

ESP32-S3 · 22.52 × 18 mm

Compute

MCU

ESP32-S3

Clock

240 MHz

SRAM · Flash

512 KB · 4MB

Radio

Wi-Fi

802.11 b/g/n

Bluetooth

5.0 LE

Antenna

PCB

I/O

GPIO · ADC

32 · 16

UART · I²C · SPI

3 · 2 · 4

PWM

8 channels

Power

USB

USB-C

Serial

Native (CDC)

Boot address

0x0

Flashing

Upload · OTA

esptool_py · esp_ota

Flash · Boot mode

QIO · QIO

Sketch · Data

1.25 MB · 320 KB

22.52 × 18 mm · pin pitch 2.54 mm

The ESP32-S3 Super Mini uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is QIO with QIO boot mode. The maximum sketch size is 1.25 MB with 320 KB available for data.

About this board

At 22.52 × 18 mm it's among the smallest boards in the whole ESP32 family.

Inside sits the ESP32-S3 - a dual-core Xtensa with vector extensions suited to AI workloads. Sibling Super Mini boards cover the ESP32-C3, ESP32-C6 and ESP32-H2, so you can change radios or horsepower without changing the footprint.

It's the only ESP32-S3 option in the Super Mini family.

Expect to pay about $5.00 - in line with other Super Mini boards.

Onboard you'll find an addressable RGB LED (GPIO48), status LEDs (Power, Charge) and Reset/Boot buttons.

It flashes over native USB - no serial-converter driver needed.

The ESP32-S3 SuperMini is a compact and powerful IoT development board based on the Espressif ESP32-S3 WiFi/Bluetooth dual-mode chip. Featuring a dual-core Xtensa LX7 processor running up to 240 MHz, it delivers impressive performance for your embedded projects.

For seamless wireless connectivity, it supports WiFi 802.11b/g/n and Bluetooth 5 (LE), making it ideal for IoT applications. Just like the ESP32-C3 SuperMini, this board includes a built-in PCB antenna, ensuring reliable signal strength without requiring an external antenna.

Equipped with 512 KB SRAM and 4 MB flash memory, there's plenty of space for your firmware and applications. Its ultra-compact design (22.52 x 18 mm) makes it easy to embed into small projects

Wondering how the ESP32-S3 SuperMini compares to other SuperMini boards? Check out our full comparison guide to see how it stacks up against the C3, C3 Plus, C6, and H2.

Ultra-small size: 22.52 x 18 mm
Ultra-low power consumption: deep sleep power consumption of about 43μA
Onboard WS2812 RGB LED for programmable multi-color status indication
Dual-core Xtensa LX7 CPU running at up to 240 MHz
512 KB SRAM, 384 KB ROM built-in, with 4 MB Flash
Secure encryption features: AES-128/256, RSA, HMAC, digital signatures, and secure startup
2 MB embedded PSRAM (ESP32-S3FH4R2) - disabled by default, enable QSPI PSRAM in your build settings

Where to buy

prices are typical street prices

ESP32-S3 Super Mini

$5.00per unit, typical

AMZAmazon.com↗ DEAmazon.de↗ ALIAliExpress↗

3D-printed case

We offer a variety of enclosures for the ESP32 S3 Super Mini, available in different colors and configurations – with or without header…

EView on EtsyEU-only shipping↗

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Resources

Board datasheet ae01.alicdn.com↗ ESP32-S3 datasheet espressif.com↗ ESP32-S3 SuperMini Development Board User Manual manuals.plus↗Hackaday - Simple Antenna Makes For Better ESP32-C3 WiFi (S3 reports in comments) hackaday.com↗ESP32-S3 Super Mini test template (chip variant, PSRAM, upload quirks) github.com↗

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