ESP32-S3-Zero
Minimalist ESP32-S3 board with Wi-Fi, BLE, and USB - perfect for low-cost, compact AIoT and wireless projects.
ESP32-S3-Zero Pinout
30 pins · 2.54 mm pitch
| 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 |
| 4 | 1 | IO1 | safe | adc | GPIO, ADC |
| 5 | 2 | IO2 | safe | adc | GPIO, ADC |
| 6 | 3 | IO3 | strapping | adc | GPIO, ADC |
| 7 | 4 | IO4 | safe | adc | GPIO, ADC |
| 8 | 5 | IO5 | safe | adc | GPIO, ADC |
| 9 | 6 | IO6 | safe | adc | GPIO, ADC |
| 10 | 7 | IO7 | safe | adc | GPIO, ADC |
| 11 | 8 | IO8 | safe | adc | GPIO, ADC |
| 12 | 9 | IO9 | strapping | adc | GPIO, ADC |
| 13 | 10 | IO10 | strapping | adc | GPIO, ADC |
| 14 | 11 | IO11 | strapping | adc | GPIO, ADC |
| 15 | 12 | IO12 | strapping | adc | GPIO, ADC |
| 16 | 43 | TXIO43 | uart | uart | GPIO, UART0 TX - the board prints TX |
| 17 | 44 | RXIO44 | uart | uart | GPIO, UART0 RX - the board prints RX |
| 18 | 13 | IO13 | strapping | adc | GPIO, ADC |
| 19 | 14 | IO14 | strapping | adc | GPIO, ADC |
| 20 | 15 | IO15 | safe | adc | GPIO, ADC |
| 21 | 16 | IO16 | safe | adc | GPIO, ADC |
| 22 | 21 | IO21 | safe | - | GPIO; drives the on-board WS2812 RGB LED (DIN) - not brought out on a pad |
| 23 | 17 | IO17 | safe | adc | GPIO, ADC |
| 24 | 18 | IO18 | safe | adc | GPIO, ADC |
| 25 | 38 | IO38 | safe | - | GPIO |
| 26 | 39 | IO39 | strapping | - | GPIO |
| 27 | 40 | IO40 | strapping | - | GPIO |
| 28 | 41 | IO41 | strapping | - | GPIO |
| 29 | 42 | IO42 | strapping | - | GPIO |
| 30 | 45 | IO45 | strapping | - | GPIO |
Start with these
13 pins with no boot or system involvementFreely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
14 pins · 9 things to knowIO3 Bootstrapping pin (controls JTAG signal source) Strapping
Sampled at reset to select JTAG interface (USB Serial/JTAG controller vs. external pins). Improper use can disable external JTAG or alter debug interface.
IO9IO10IO11IO12IO13IO14 General-purpose SPI2 (FSPI) IO MUX pins Other
IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet lists it as a priority-2 pin ("can be freely used without restrictions"), so it is only taken if your board wires flash, an SD card or a display to FSPI.
- IO9General-purpose SPI2 (FSPI) IO MUX pin - hold/data line (FSPIHD)
- IO10General-purpose SPI2 (FSPI) IO MUX pin - chip select (FSPICS0)
- IO11General-purpose SPI2 (FSPI) IO MUX pin - data in (FSPID)
- IO12General-purpose SPI2 (FSPI) IO MUX pin - clock (FSPICLK)
- IO13General-purpose SPI2 (FSPI) IO MUX pin - data out (FSPIQ)
- IO14General-purpose SPI2 (FSPI) IO MUX pin - write-protect/data line (FSPIWP)
TXGPIO43 UART0 transmit pin (U0TXD), default serial console TX UART
Used for bootloader output and UART console logs. If repurposed, you will lose the default serial output (and programming via UART0).
RXGPIO44 UART0 receive pin (U0RXD), default serial console RX UART
Used for bootloader input (download mode via serial). If repurposed, you cannot use the default UART0 download mode for programming the chip.
IO39 JTAG test clock (MTCK); IO MUX alternates CLK_OUT3 and SUBSPICS1 (chip select on the alternative SUBSPI memory bus, unused on standard modules) JTAG
Default JTAG TCK - keep it free if you debug over JTAG. It is not a flash or PSRAM line on standard modules: those sit on GPIO26-37.
IO40 JTAG test data out pin (MTDO) JTAG
Default JTAG TDO output for debugging. Using it as GPIO will interfere with JTAG debugging functionality.
IO41 JTAG test data in pin (MTDI) JTAG
Default JTAG TDI input for debugging. Should be reserved for JTAG or left unused if JTAG is to remain available.
IO42 JTAG test mode select pin (MTMS) JTAG
Default JTAG TMS signal for debugging. Using this pin for other purposes will disable the JTAG interface (unless JTAG is rerouted to USB).
IO45 Bootstrapping pin (selects VDD_SPI flash voltage) Strapping
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.
Across 30 pins (2.54 mm pitch), the ESP32-S3-Zero exposes 27 GPIO plus 5V, GND and 3V3 for power.
Peripheral wiring is straightforward: TX/RX on GPIO43 and GPIO44 cover serial logging and flashing.
Beyond plain digital I/O you get 18 ADC-capable pins for sensors and battery monitoring.
14 of the exposed pins carry boot-time or system duties on the ESP32-S3 (IO3, IO9, IO10 and 11 more) - check the guidance above before wiring anything to them. IO1, IO2, IO4, IO5 and 9 more are free of any such role - the safest first picks.
Pinout notes 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…
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.
Getting started
flash your first firmware in ~2 minutesBoard: ESP32S3 Dev Module USB CDC On Boot: Enabled Flash Size: 4MB (32Mb) Flash Mode: QIO PSRAM: QSPI PSRAM Partition Scheme: Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS) Upload Speed: 921600
// toggle GPIO1 - wire an LED and resistor to it
void setup() {
pinMode(1, OUTPUT);
}
void loop() {
digitalWrite(1, HIGH); delay(500);
digitalWrite(1, LOW); delay(500);
}[env:esp32-s3-zero]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_qspi
build_flags = -DBOARD_HAS_PSRAMesp32-s3-devkitc-1 - or type it after board =.esp32:
board: esp32-s3-devkitc-1
variant: esp32s3
framework:
type: esp-idf
psram:
mode: quad
speed: 80MHz
# blink - GPIO1
output:
- platform: gpio
pin: 1
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesp32-s3-devkitc-1 (same ids as PlatformIO).esptool.py --chip esp32s3 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x0 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Good to know
board-specific quirks worth 60 seconds
If you're following a generic ESP32-S3 tutorial and it references GPIO33 through GPIO37 - stop looking for them. Waveshare's official wiki is explicit: "The ESP32-S3-Zero does not break out GPIO33~GPIO37; these pins are reserved for Octal PSRAM." It's a routing decision, not a defect - the module's PSRAM footprint claims those lines even though this board's 2 MB PSRAM is quad-mode. Plan your pin budget around the…
If you're following a generic ESP32-S3 tutorial and it references GPIO33 through GPIO37 - stop looking for them. Waveshare's official wiki is explicit: "The ESP32-S3-Zero does not break out GPIO33~GPIO37; these pins are reserved for Octal PSRAM."
It's a routing decision, not a defect - the module's PSRAM footprint claims those lines even though this board's 2 MB PSRAM is quad-mode. Plan your pin budget around the GPIOs that are actually on the header and castellated edge.
The S3-Zero uses the same ESP32-S3FH4R2 as the S3 SuperMini: 4 MB flash and 2 MB quad-SPI PSRAM inside the chip package. Waveshare states it plainly, but default board profiles still ship with PSRAM disabled. In Arduino IDE set Tools → PSRAM → "QSPI PSRAM" (not OPI - that's for octal chips and will crash). In ESPHome use psram: with mode: quad; in PlatformIO, board_build.arduino.memory_type = qio_qspi plus…
The S3-Zero uses the same ESP32-S3FH4R2 as the S3 SuperMini: 4 MB flash and 2 MB quad-SPI PSRAM inside the chip package. Waveshare states it plainly, but default board profiles still ship with PSRAM disabled.
In Arduino IDE set Tools → PSRAM → "QSPI PSRAM" (not OPI - that's for octal chips and will crash). In ESPHome use psram: with mode: quad; in PlatformIO, board_build.arduino.memory_type = qio_qspi plus -DBOARD_HAS_PSRAM.
Verify with ESP.getPsramSize() - it returns 0 until the setting is right.
There's no USB-serial chip - USB-C goes straight to the S3's native USB. Waveshare's documented download procedure is to hold the BOOT (GPIO0) button before connecting the USB-C cable, then flash; press RESET afterwards to run your firmware. If an upload fails mid-way or the COM port vanishes, that button dance is the fix - a common stumbling block for first-time users. And as with all native-USB S3 boards: enable…
There's no USB-serial chip - USB-C goes straight to the S3's native USB. Waveshare's documented download procedure is to hold the BOOT (GPIO0) button before connecting the USB-C cable, then flash; press RESET afterwards to run your firmware. If an upload fails mid-way or the COM port vanishes, that button dance is the fix - a common stumbling block for first-time users.
And as with all native-USB S3 boards: enable Tools → USB CDC On Boot → "Enabled" or Serial.print() output goes to the UART pins (GPIO43/44) instead of your serial monitor.
The castellated half-hole edges mean the S3-Zero doubles as a surface-mount module: design a footprint on your carrier board and reflow or hand-solder the whole thing down - no headers, no sockets. That's the "Zero" use case, and it's why the board keeps its components on one side. Two integration facts from the official docs: the ME6217 regulator (800 mA) accepts 3.7-6 V on the 5V pad, so a lithium cell can drive…
The castellated half-hole edges mean the S3-Zero doubles as a surface-mount module: design a footprint on your carrier board and reflow or hand-solder the whole thing down - no headers, no sockets. That's the "Zero" use case, and it's why the board keeps its components on one side.
Two integration facts from the official docs: the ME6217 regulator (800 mA) accepts 3.7-6 V on the 5V pad, so a lithium cell can drive it directly - but there's no charging circuit, so charge the cell externally. And keep the area around the ceramic antenna free of copper and metal on your carrier board - Waveshare explicitly warns that covering it degrades the signal.
Downloads
Free for non-commercial use, credit espboards.dev · License
Board illustration
The bare ESP32-S3-Zero board drawn to scale at 23.5 × 18 mm, with no pin labels on it. Made for slide decks, wiring diagrams and project write-ups where a photo is too busy. Take the scalable SVG for print or editing, the high-resolution PNG to drop straight in, or the transparent PNG when you need it with no background behind it.
Pinout diagram
Every pin on both sides of the board with its functions, drawn by ESPboards from the ESP32-S3 Series Datasheet v2.2 - the same sheet shown at the top of this page. The PNG is a high-resolution image for screens, the SVG is vector so it stays sharp at any size, and the PDF is laid out to print on A4 or Letter.
Yours to use, share and adapt for non-commercial work, as long as you credit espboards.dev - the full terms and ready-made credit lines are here.
Specifications
ESP32-S3 · 23.5 × 18 mm · vs other ESP32 chips →Dimensions
About this board
At 23.5 × 18 mm it's the smallest Zero-format board we've measured.
Inside sits the ESP32-S3 - a dual-core Xtensa with vector extensions suited to AI workloads. Sibling Zero-format boards cover the ESP32-C3 and ESP32-C6, so you can change radios or horsepower without changing the footprint.
It's the only ESP32-S3 option in the Zero-format family.
The $6.27 price tag is typical for a Zero-format board.
Around the module: 2MB (QSPI) PSRAM, an addressable RGB LED (GPIO21) and Reset/Boot buttons.
It flashes over native USB - no serial-converter driver needed.
The ESP32-S3-Zero is Waveshare's entry in the tiny-S3 class - and unlike most boards this size, it's an actual branded product with a real wiki behind it. It packs the ESP32-S3FH4R2 (dual-core 240 MHz, 4 MB flash + 2 MB PSRAM in-package, 512 KB SRAM) with WiFi and BLE 5 into a 23.5 x 18 mm footprint.
Two design choices define it: a USB-C port wired straight to the S3's native USB (no serial chip), and castellated half-hole edges so the whole board can be soldered onto a carrier PCB like a module. A WS2812 RGB LED on GPIO21 serves as the status light, and BOOT + RESET buttons handle flashing.
Power is flexible for integrators: the ME6217 regulator (800 mA) accepts 3.7-6 V on the 5V pad, so it runs from USB, a lithium cell, or a small wall supply - though note there is no battery charging circuit on board.
- 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
Where to buy
prices are typical street pricesResources
Similar boards
All Zero boards →
