ESP32-C3 OLED 0.42" Display

Development Board

Code name: ESP32C3_DEV

ESP32-C3 OLED 0.42" Display 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 OLED 0.42" Display

The ESP32-C3 OLED 0.42" is a compact development board featuring the ESP32-C3 RISC-V microcontroller with integrated Wi-Fi 802.11 b/g/n and Bluetooth 5 (LE) connectivity. 📶

Powered by a 32-bit RISC-V single-core processor running at up to 160 MHz, with 4MB flash memory and 400KB SRAM, it's perfect for IoT applications and embedded projects. ⚡

The board features a built-in 0.42" OLED display with 72x40 resolution connected via I2C, ideal for displaying sensor data, status information, or user interfaces. It offers 13 GPIO pins with support for ADC (6 channels, 12-bit), PWM, and various communication interfaces including UART, SPI, I2C, and I2S. 🔌

Operating at 3.3V with Micro-USB interface for programming and power. Ultra-compact design makes it suitable for wearable and space-constrained applications. 🔋

Where to Buy ESP32-C3 OLED 0.42" Display

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$8.99

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Technical Specifications

Complete technical specification details for ESP32-C3 OLED 0.42" Display

Display

Type OLED

USB

Type Micro-USB

Serial Chip CP2102

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 13

Analog Input 6

PWM 11

Interrupts 22

• OLED Screen

Download Full Datasheet

Quick Setup

Copy-paste configs for ESP32-C3 OLED 0.42" Display - auto‑generated from this board's exact hardware specs.

ESP32C3 160 MHz 4MB QIO RISC-V

In Arduino IDE 2 select Esp32c3 Dev from the esp32 by Espressif package. In PlatformIO use board = esp32-c3-devkitm-1. ESP32C3 · 160 MHz · 4MB · QIO · RISC-V.

Tools menu settings

Board (select in Arduino IDE) Esp32c3 Dev

CPU Frequency 160 MHz

Flash Size 4MB

Flash Mode QIO

Upload Speed 921600

Architecture RISC-V

In Arduino IDE 2, open Boards Manager, search "esp32" by Espressif and install it. Then go to Tools → Board and select "Esp32c3 Dev" for the ESP32-C3 OLED 0.42" Display.

platformio.ini


[env:esp32-c3-oled-042]
platform  = espressif32
board     = esp32-c3-devkitm-1
framework = arduino

; Exact hardware config for ESP32-C3 OLED 0.42&quot; Display
board_build.mcu        = esp32c3
board_build.f_cpu      = 160000000L
board_build.flash_size = 4MB
board_build.flash_mode = qio
board_upload.flash_size = 4MB

The board value is a close generic match - check PlatformIO board registry for an exact fit.

esp32: block (YAML)


esp32:
  board: esp32-c3-devkitm-1
  framework:
    type: arduino   # or "esp-idf"

# ESP32-C3 OLED 0.42&quot; Display - 160 MHz ESP32C3
# Flash: 4MB | USB: Micro-USB

Paste into your device's .yaml. See ESPHome ESP32 docs for full options.

esptool.py - flash command


esptool.py \
  --chip esp32c3 \
  --baud 921600 \
  write_flash \
    --flash_mode qio \
    --flash_size 4MB \
    0x0 bootloader.bin \
    0x8000    partitions.bin \
    0xe000    boot_app0.bin \
    0x10000   firmware.bin

Install: pip install esptool - replace firmware.bin with your binary - bootloader at 0x0

ESP32-C3 OLED 0.42" Display Pinout Diagram

Complete pin reference for ESP32-C3 OLED 0.42" Display

The ESP32-C3 OLED 0.42" pinout provides 13 GPIO pins in a compact layout. Power pins include 3V3 for 3.3V supply and GND for ground connection.

The integrated 0.42" OLED display uses I2C communication (typically GPIO 8 for SDA and GPIO 9 for SCL). GPIO pins support digital I/O, ADC, PWM, and multiple protocols.

Communication pins include RX and TX for UART, while other GPIOs can be configured for SPI, I2C, PWM, and more. ADC channels provide 12-bit analog input.

Safe Pins to Use

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

IO08

IO09

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
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 OLED 0.42" Display Additional Information

More details about ESP32-C3 OLED 0.42" Display

ESP32-C3 OLED 0.42" Features

📺 Built-in Display

0.42" OLED Screen: 72x40 resolution with high contrast
I2C Interface: Connected to GPIO 8 (SDA) and GPIO 9 (SCL)
Driver: SSD1306 controller for easy integration

⚙️ Technical Specifications

Based on ESP32-C3 RISC-V processor with 13 GPIO pins. Perfect for projects requiring visual feedback in ultra-compact form factors.

💡 Perfect For

Ideal for wearable devices, smart sensors, mini IoT projects, and applications where a tiny display is essential without external components.

Useful Links

Datasheets and resources for ESP32-C3 OLED 0.42" Display

Board Datasheet

Technical specifications

ESP32C3 Datasheet

Microcontroller reference

ESP32-C3 0.42 OLED Schematic

https://github.com/zhuhai-esp/ESP32-C3-ABrobot-OLED/blob/main/Document/ESP32C3%20OLED%E5%8E%9F%E7%90%86%E5%9B%BE.pdf

ESP32-C3 OLED 0.42" Display Custom Pin Mapping

Pin configuration and GPIO mapping for ESP32-C3 OLED 0.42" Display

Digital I/O Pins

Interrupt Pins

Analog Inputs

PWM Pins

Pin	Function	ESP Pin	I/O Type	Description
1	IO08	GPIO8	BIDIRECTIONAL	I2C Data Line for OLED
2	IO09	GPIO9	BIDIRECTIONAL	I2C Clock Line for OLED
3	IO0	GPIO0	BIDIRECTIONAL	GPIO0, ADC0
4	IO1	GPIO1	BIDIRECTIONAL	GPIO1, ADC1
5	IO2	GPIO2	BIDIRECTIONAL	GPIO2, ADC2
6	IO3	GPIO3	BIDIRECTIONAL	GPIO3, ADC3
7	IO4	GPIO4	BIDIRECTIONAL	GPIO4, ADC4, SCK
8	IO5	GPIO5	BIDIRECTIONAL	GPIO5, ADC5, MISO
9	IO6	GPIO6	BIDIRECTIONAL	GPIO6, MOSI
10	IO7	GPIO7	BIDIRECTIONAL	GPIO7, SS
11	IO10	GPIO10	BIDIRECTIONAL	GPIO10, RX
12	IO20	GPIO20	BIDIRECTIONAL	GPIO20, RX
13	IO21	GPIO21	BIDIRECTIONAL	GPIO21, TX

Legend

Function Pin role

GPIO ESP32 pin

I/O Direction

# Pin number

Pin Mappings

Complete pinout and GPIO mapping for ESP32-C3 OLED 0.42" Display

Digital I/O Pins

Interrupt Pins

Analog Inputs

PWM Pins

Pin	Analog	Other
0	A0
1	A1
2	A2
3	A3
4	A4	SCK
5	A5	MISO
6		MOSI
7		SS
8		SDA
9		SCL
10		RX
20		RX
21		TX

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 OLED 0.42" Display

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)