ESP32-S3-Zero Development Board

Code name: ESP32S3_DEV

ESP32-S3-Zero 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 4MB.

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

About ESP32-S3-Zero

The ESP32-S3-Zero is a compact development board featuring the Espressif ESP32-S3FH4R2 dual-core processor, operating at up to 240MHz. It offers 2.4GHz Wi-Fi (802.11 b/g/n) and Bluetooth 5 (LE) capabilities, making it ideal for IoT projects requiring robust wireless connectivity. 📶

With its small form factor of 23.5 × 18 mm, the board is designed for easy integration into space-constrained applications. The onboard ceramic antenna ensures stable wireless performance without the need for an external antenna.

For user convenience, the ESP32-S3-Zero includes both a BOOT button and a RESET button, facilitating straightforward development and debugging processes. 🚀

Equipped with 24 multifunctional GPIO pins, the board supports various interfaces, including:

4 × SPI
2 × I2C
3 × UART
2 × I2S
2 × ADC

Where to Buy

Starting from

$6.27 per unit

Amazon.com Ships worldwide

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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.

Technical Specifications

🛰️ 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 4MB

Architecture xtensa

✨ Features

Ultra-compact size: 23.5 × 18 mm
Low power consumption: supports various power modes for energy-efficient applications
Onboard WS2812 RGB LED connected to GPIO21
24 digital IO pins
24 external interrupt pins
2 analog input pins
24 PWM pins

View Full Datasheet

ESP32-S3-Zero Dimensions

Width 18.00 mm

Length 23.50 mm

Pin Gap 2.54 mm

ESP32-S3-Zero Pinout

The ESP32-S3-Zero pinout is engineered for versatility within a compact footprint. Key power pins include 5V, 3.3V, and GND, ensuring reliable power delivery for various peripherals.

The board offers multiple communication interfaces:

UART: TX (GPIO43), RX (GPIO44)
I2C: SDA, SCL
SPI: SCK, MISO, MOSI, SS

For analog input, it provides ADC pins suitable for reading sensor data or voltage levels.

✅ Safe Pins to Use

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

🔹 IO1

🔹 IO2

🔹 IO4

🔹 IO5

🔹 IO6

🔹 IO7

🔹 IO8

🔹 IO15

🔹 IO16

🔹 IO17

🔹 IO18

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
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
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

ESP32-S3-Zero Useful Links

🔗 Datasheet

hhttps://www.waveshare.com/wiki/ESP32-S3-Zero

🔗 ESP32S3 Datasheet

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

ESP32-S3-Zero Pin Mappings

This development board provides 24 digital IO pins, out of which 24 can be used as external interrupt pins , 2 as analog input pins and 24 pins have Pulse-Width Modulation (PWM) .

Pin	Function	ESP Pin	Input/Output	Description
1	5V	5V	POWER INPUT	5V power input for the board
2	GND	GND	POWER GROUND	Ground connection
3	3V3	3.3V	POWER OUTPUT	3.3V power output
5	IO1	IO1	BIDIRECTIONAL	GPIO, ADC
6	IO2	IO2	BIDIRECTIONAL	GPIO, ADC
7	IO3	IO3	BIDIRECTIONAL	GPIO, ADC
8	IO4	IO4	BIDIRECTIONAL	GPIO, ADC
9	IO5	IO5	BIDIRECTIONAL	GPIO, ADC
10	IO6	IO6	BIDIRECTIONAL	GPIO, ADC
11	IO7	IO7	BIDIRECTIONAL	GPIO, ADC
12	IO8	IO8	BIDIRECTIONAL	GPIO, ADC
13	IO9	IO9	BIDIRECTIONAL	GPIO, ADC
14	IO10	IO10	BIDIRECTIONAL	GPIO, ADC
15	IO11	IO10	BIDIRECTIONAL	GPIO, ADC
16	IO12	IO10	BIDIRECTIONAL	GPIO, ADC
17	IO13	IO10	BIDIRECTIONAL	GPIO, ADC
18	IO14	IO10	BIDIRECTIONAL	GPIO, ADC
19	IO15	IO10	BIDIRECTIONAL	GPIO, ADC
20	IO16	IO10	BIDIRECTIONAL	GPIO, ADC
21	IO17	IO10	BIDIRECTIONAL	GPIO, ADC
22	IO18	IO10	BIDIRECTIONAL	GPIO, ADC
23	IO38	IO10	BIDIRECTIONAL	GPIO
24	IO39	IO10	BIDIRECTIONAL	GPIO
25	IO40	IO10	BIDIRECTIONAL	GPIO
26	IO41	IO10	BIDIRECTIONAL	GPIO
27	IO42	IO10	BIDIRECTIONAL	GPIO
28	IO45	IO10	BIDIRECTIONAL	GPIO

Function Pin Function

ESP Pin Pin on ESP32

I/O Input/Output Pin

Description Pin Description

Default Tools

Bootloader tool	esptool_py
Uploader tool	esptool_py
Network uploader tool	esp_ota
Bootloader address	0x0
Flash mode	qio
Boot mode	qio
Maximum upload size	4096 Kb (4194304 B)
Maximum data size	512 Kb (524288 B)

The ESP32-S3-Zero 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 ESP32-S3-Zero development board by default is qio and qio respectively.