ESP32-C3-Zero Pro
Upgraded ESP32-C3 Zero with enhanced features - ideal for compact projects needing extra I/O or functionality.
Pinout
16 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 | 0 | IO0GPIO0 | safe | adc · pwm | GPIO, ADC, PWM |
| 5 | 1 | IO1GPIO1 | safe | adc · pwm | GPIO, ADC, PWM |
| 6 | 2 | IO2GPIO2 | strapping | adc · pwm | GPIO, ADC, PWM |
| 7 | 3 | IO3GPIO3 | safe | adc · pwm | GPIO, ADC, PWM |
| 8 | 4 | IO4GPIO4 | strapping | adc · spi · pwm | GPIO, ADC, SPI SCK, PWM |
| 9 | 5 | IO5GPIO5 | strapping | adc · spi · pwm | GPIO, ADC, SPI MISO, PWM |
| 10 | 6 | IO6GPIO6 | strapping | spi · pwm | GPIO, SPI MOSI, PWM |
| 11 | 7 | IO7GPIO7 | strapping | spi · pwm | GPIO, SPI SS, PWM |
| 12 | 8 | IO8GPIO8 | strapping | i2c · pwm | GPIO, I2C Data line, PWM |
| 13 | 9 | IO9GPIO9 | strapping | i2c · pwm | GPIO, I2C Clock line, PWM |
| 14 | 10 | IO10GPIO10 | safe | - | GPIO |
| 15 | 20 | IO20RX | uart | uart | GPIO, UART Transmit |
| 16 | 21 | IO21TX | uart | uart | GPIO, UART Transmit |
Start with these
4 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
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| 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 |
| 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 |
Pinout notes Across 16 pins (2.54 mm pitch), the ESP32-C3-Zero Pro exposes 13 GPIO plus 5V , GND and 3V3 for power. Peripheral wiring is straightforward: TX / RX on GPIO21…
Across 16 pins (2.54 mm pitch), the ESP32-C3-Zero Pro exposes 13 GPIO plus 5V, GND and 3V3 for power.
Peripheral wiring is straightforward: TX/RX on GPIO21 and GPIO20 cover serial logging and flashing.
Beyond plain digital I/O you get 6 ADC-capable pins for sensors and battery monitoring and PWM on 10 pins.
9 of the exposed pins carry boot-time or system duties on the ESP32-C3 (IO2, IO4, IO5 and 6 more) - check the guidance above before wiring anything to them. IO0, IO1, IO3 and IO10 are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutesBoard: Esp32c3 Dev
USB CDC On Boot: Enabled
Flash Size: 4MB · QIO
Upload Speed: 921600
// blink
pinMode(0, OUTPUT);
digitalWrite(0, LOW); // on (often inverted)[env:esp32-c3-zero-pro]
platform = espressif32
board = esp32-c3-devkitm-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32-c3-devkitm-1
variant: esp32c3
framework:
type: esp-idf
# blink - GPIO0
output:
- platform: gpio
pin: 0
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesptool.py --chip esp32c3 --port /dev/ttyACM0 \
write_flash 0x0 firmware.binSpecifications
ESP32-C3 · 22.52 × 18 mmAbout this board
At 22.52 × 18 mm it's the smallest Zero-format board we've measured.
Inside sits the ESP32-C3 - a single-core RISC-V and the budget low-power pick. Sibling Zero-format boards cover the ESP32-C6 and ESP32-S3, so you can change radios or horsepower without changing the footprint.
At $3.00 it's cheaper than most Zero-format boards, which usually run around $6.27.
Around the module: an addressable RGB LED (GPIO10) and Reset/Boot buttons.
It flashes over native USB - no serial-converter driver needed.
ESP32-C3-Zero Pro is an upgraded version of the ESP32-C3-Zero, featuring a better ceramic antenna and an IPEX antenna mount for improved wireless performance. It is based on the Espressif ESP32-C3 Wi-Fi/Bluetooth dual-mode chip, with a 32-bit RISC-V single-core processor running at up to 160 MHz. It comes with 400 KB SRAM, 384 KB ROM, and 4 MB of onboard flash memory.
This board supports 2.4 GHz Wi-Fi (802.11 b/g/n) and Bluetooth 5 (LE), making it ideal for low-power IoT applications and wireless wearable devices.
Compared to the ESP32-C3-Zero, the Zero Pro offers enhanced signal strength due to its dual-antenna design, making it more reliable for applications requiring strong wireless connectivity. It retains the same ultra-compact footprint (22.52 × 18 mm) while adding more connectivity options.
For user convenience, it includes both a RESET button and a BOOT button to facilitate development and debugging.
The board provides 11 digital I/O pins configurable as PWM outputs and 4 analog I/O pins for ADC inputs. It supports multiple serial interfaces, including 1× I2C, 1× SPI, and 2× UART, ensuring compatibility with a wide range of peripherals.
- Improved wireless performance: Better ceramic antenna + IPEX antenna mount
- Ultra-small size: 22.52 × 18 mm
- Ultra-low power consumption: deep sleep current approximately 43 μA
- Onboard blue LED connected to GPIO8
Where to buy
prices are typical street pricesResources
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