ET-M18

ATmega32U4 USB-C Board

Name: ATmega32U4 USB-C Board
Brand: ElectroTrical
SKU: ET-M18
Price: 59.00 AED
Availability: OutOfStock

Pro Micro-style 5 V Arduino with native USB HID and Qwiic

AED 59.00

Out of stock

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Download datasheet (PDF)

Overview Key features Specifications Performance Pinout

Overview

Pro Micro-style 5 V Arduino with native USB HID and Qwiic

The ET-M18 is built around the Microchip ATmega32U4 — AVR 16MHz at 5V, 32KB flash, 2.5KB RAM, native USB 2.0 full speed.

Two Qwiic / STEMMA QT connectors let you chain it with other boards without soldering, and the 2.54 mm header fits a breadboard.

Designed in Dubai by ElectroTrical — the full schematic, BOM and design notes are published below.

Good for

Custom keyboards (QMK)
USB game controllers
5 V Arduino projects

Key features

What makes it different

MCU

Microchip ATmega32U4: AVR 16MHz at 5V, 32KB flash, 2.5KB RAM, native USB 2.0 full speed

USB

USB-C; factory DFU bootloader (Arduino 'Leonardo' bootloader can be flashed over ISP)

I/O

18 signals on the header incl. 9 analog inputs, Qwiic at 3.3V with level shifting

Power

5V USB-C direct; AP2112K 3.3V for the Qwiic side

Qwiic / STEMMA QT

Two JST-SH connectors plus a 2.54 mm header — 3.3 V and 5 V hosts.

Open documentation

Schematic, BOM and layout notes published for every board.

Specifications

Technical specifications

Device
MCU	Microchip ATmega32U4: AVR 16MHz at 5V, 32KB flash, 2.5KB RAM, native USB 2.0 full speed
USB	USB-C; factory DFU bootloader (Arduino 'Leonardo' bootloader can be flashed over ISP)
I/O	18 signals on the header incl. 9 analog inputs, Qwiic at 3.3V with level shifting
Power	5V USB-C direct; AP2112K 3.3V for the Qwiic side

Board
Size	45.7 × 25.4 mm
Mounting	4 × M2.5 holes, 2.54 mm from each corner
Connectors	2 × Qwiic / STEMMA QT (JST SH 4-pin) · 22-pin 2.54 mm header · USB-C 16P receptacle (USB 2.0) — USB-C
Main IC	ATMEGA32U4-AU (LCSC C44854)
Revision	Rev A

Software
Libraries	Arduino (Leonardo / Pro Micro), QMK keyboard firmware, LUFA

Performance

Memory

Flash and RAMFrom the ATmega32U4 datasheet.

Flash32 KB

RAM2.5 KB

EEPROM1 KB

Pinout

Pin map and connections

Pin	Name	Type	Function
1	`VBUS`	Power	5V from USB-C (MCU runs at 5V)
2	`3V3`	Power	LDO output for 3.3V parts
3	`GND`	Ground	Ground
4	`RESET`	Control	Reset, active low
5	`PD3`	GPIO	TX1
6	`PD2`	GPIO	RX1
7	`PD4`	GPIO	A6 / D4
8	`PC6`	GPIO	D5 / PWM
9	`PD7`	GPIO	A7 / D6 / PWM
10	`PE6`	Signal	D7 / INT6
11	`PB4`	GPIO	A8 / D8
12	`PB5`	GPIO	A9 / D9 / PWM
13	`PB6`	GPIO	A10 / D10 / PWM
14	`PB2`	GPIO	MOSI / D16
15	`PB3`	GPIO	MISO / D14
16	`PB1`	GPIO	SCK / D15
17	`PF4`	Signal	A3
18	`PF5`	Signal	A2
19	`PF6`	Signal	A1
20	`PF7`	Signal	A0
21	`SDA`	I²C	PD1 — I²C SDA, 5V side
22	`SCL`	I²C	PD0 — I²C SCL, 5V side

Qwiic / STEMMA QT pins: GND, VIN, SDA, SCL (same on both connectors).

Mechanical

Dimensions and what's in the box

Board 45.7 × 25.4 mm with M2.5 holes — Top view · 45.7 × 25.4 mm

In the box

1 × ET-M18 ATmega32U4 USB-C Board (assembled)
1 × 22-pin 2.54 mm male header, unsoldered

Getting started

Plug in a Qwiic / STEMMA QT cable, or solder the header and wire VIN, GND, SDA and SCL
Libraries: Arduino (Leonardo / Pro Micro), QMK keyboard firmware, LUFA

Compare

Which 5 V Arduino-style board?

	ATmega32U4 USB-C Board (this board)This board	ET-M08 ATmega328PB Nano-Style Board
What it does	Pro Micro-style 5 V Arduino with native USB HID and Qwiic	Arduino-compatible 16 MHz board with USB-C and 5 V Qwiic
Interface	—	—
Best for	Custom keyboards (QMK)	Arduino classes and kits
Price	59 AED	39 AED

Downloads

Documents and design files

PDFET-M18 schematicRev A LCSCATMEGA32U4-AU datasheet and stockC44854

STEP3D modelComing soon

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