ESP32 C3 Zero

Development Board

Code name: ESP32C3_DEV

ESP32 C3 Zero is a development board based on the ESP32C3 microcontroller using RISCV32 architecture.

This board features a maximum CPU frequency of 160 MHz and 4MB flash memory.

About ESP32 C3 Zero

The ESP32-C3-Zero is a compact development board featuring the Espressif ESP32-C3FN4 chip. It offers 2.4GHz Wi-Fi (802.11 b/g/n) and Bluetooth 5 (LE), making it ideal for IoT projects needing reliable wireless connectivity. 📶

Its small form factor makes it easy to integrate into space-constrained projects, and the onboard ceramic antenna ensures stable wireless performance without requiring an external antenna.

For ease of use, it includes a BOOT button and a RESET button, simplifying development and debugging. 🚀

With 15 GPIO pins and support for multiple interfaces (SPI, I2C, UART, I2S, ADC), the ESP32-C3-Zero is a flexible choice for your next embedded project! ⚙️

Where to Buy ESP32 C3 Zero

Starting from

$4.90 per unit

Amazon.com Ships worldwide

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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 ESP32 C3 Zero

🛰️ Connectivity

WiFi 802.11 b/g/n (2.4 GHz)

Bluetooth 5.0

BLE 5.0

🧠 Microcontroller

Model esp32c3

Clock Speed 160 MHz

Flash Size 4MB

Architecture riscv32

✨ Features & Pins

Digital IO 15

Analog Input 6

PWM 15

Interrupts 22

• Ultra-compact size: 23.5 × 18 mm
• Low power consumption: deep sleep current ~43μA
• Onboard WS2812 RGB LED (GPIO8)

Download Full Datasheet

ESP32 C3 Zero Pinout Diagram

Complete pin reference for ESP32 C3 Zero

The ESP32-C3-Zero pinout is designed for maximum versatility in a compact size. Key power pins include 5V, 3.3V, and GND, ensuring stable power for various peripherals.

The board features multiple communication interfaces:

UART: RX, TX
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

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

IO0

IO1

IO3

IO10

💡 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
IO2	GPIO2	Must be held high during boot (if low on reset, normal flash boot may fail)	🛠️ Strapping
IO4	MTMS	Used during boot; JTAG TMS for debugging; acts as Quad-SPI flash IO (hold data line) in internal-flash variants	🔗 JTAG
IO5	MTDI	Used during boot; JTAG TDI for debugging; acts as Quad-SPI flash IO (write-protect data line) in internal-flash variants	🔗 JTAG
IO6	MTCK	Used during boot; JTAG TCK for debugging; provides flash clock in internal-flash variants	🔗 JTAG
IO7	MTDO	Used during boot; JTAG TDO for debugging; acts as Quad-SPI flash IO (data line) in internal-flash variants	🔗 JTAG
IO8	GPIO8	Must be held high during reset (if low, UART flashing/boot may not work)	🛠️ Strapping
IO9	GPIO9	Controls boot mode on reset (HIGH for normal flash boot, LOW enters serial download mode)	🛠️ Strapping
IO18	USB_D-	By default connected to on-chip USB Serial/JTAG controller; to use as GPIO it must be reconfigured from its USB function	🔌 USB
IO19	USB_D+	By default connected to on-chip USB Serial/JTAG controller; not available for GPIO use unless USB functionality is disabled or remapped	🔌 USB
IO20	U0RXD	Used as UART0 receive (console/bootloader); repurposing may disable serial programming and debug logs	📡 UART
IO21	U0TXD	Used as UART0 transmit (console/bootloader); repurposing may disable serial console output and printing	📡 UART

ESP32 C3 Zero Additional Information

More details about ESP32 C3 Zero

Useful Links

Datasheets and resources for ESP32 C3 Zero

Board Datasheet

Technical specifications

ESP32C3 Datasheet

Microcontroller reference

ESP32 C3 Zero Custom Pin Mapping

Pin configuration and GPIO mapping for ESP32 C3 Zero

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 GROUND	Ground connection
3	3V3	3.3V	POWER OUTPUT	3.3V power output
4	IO0	IO0	BIDIRECTIONAL	GPIO, ADC
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
10	IO6	IO6	BIDIRECTIONAL	GPIO
11	IO7	IO7	BIDIRECTIONAL	GPIO
12	IO8	SDA	BIDIRECTIONAL	GPIO
13	IO9	SCL	BIDIRECTIONAL	GPIO
14	IO10	RX	BIDIRECTIONAL	GPIO, LED
15	IO18	RX	BIDIRECTIONAL	USB DP
16	IO19	RX	BIDIRECTIONAL	USB DM
17	IO20	RX	BIDIRECTIONAL	GPIO, UART Receive (secondary)
18	IO21	TX	BIDIRECTIONAL	GPIO, UART Transmit

Legend

Function Pin role

GPIO ESP32 pin

I/O Direction

# Pin number

Pin Mappings

Complete pinout and GPIO mapping for ESP32 C3 Zero

Digital I/O Pins

Interrupt Pins

Analog Inputs

PWM Pins

Pin	Analog	Touch	PWM	Other
0				IO0
1				IO1
2				IO2
3				IO3
4				SCK IO4
5				MISO IO5
6				MOSI IO6
7				SS IO7
8				LED_BUILTIN SDA IO8
9				SCL IO9
20				RX IO20
21				TX IO21

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 ESP32 C3 Zero

Setting	Value
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	1280 KB (1310720 bytes)
Maximum data size	320 KB (327680 bytes)