ET-C12
USB-C to I²C / Qwiic Adapter
Talk to Qwiic sensors from a PC — no driver needed
AED 20.00
Out of stockOverview
Talk to Qwiic sensors from a PC — no driver needed
The ET-C12 is built around the Microchip MCP2221A — USB 2.0 FS → I²C (up to 400kHz) + UART (≤115200) + 4 GPIO (3×10-bit ADC, DAC).
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
- Testing sensors from Python
- PC-based data logging
- Production programming of I²C devices
Key features
What makes it different
Bridge
Microchip MCP2221A: USB 2.0 FS → I²C (up to 400kHz) + UART (≤115200) + 4 GPIO (3×10-bit ADC, DAC)
Drivers
HID + CDC — no driver on Windows/macOS/Linux
Use
Talk to any Qwiic sensor from a PC: Python (Adafruit Blinka, EasyMCP2221), Microchip I2C/SMBus terminal
Logic
3.3V
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
| Bridge | Microchip MCP2221A: USB 2.0 FS → I²C (up to 400kHz) + UART (≤115200) + 4 GPIO (3×10-bit ADC, DAC) |
|---|---|
| Drivers | HID + CDC — no driver on Windows/macOS/Linux |
| Use | Talk to any Qwiic sensor from a PC: Python (Adafruit Blinka, EasyMCP2221), Microchip I2C/SMBus terminal |
| Logic | 3.3V |
| Size | 25.4 × 25.4 mm |
|---|---|
| Mounting | 4 × M2.5 holes, 2.54 mm from each corner |
| Connectors | 2 × Qwiic / STEMMA QT (JST SH 4-pin) · 11-pin 2.54 mm header · USB-C 16P receptacle (USB 2.0) — USB-C |
| Main IC | MCP2221A-I/ST (LCSC C130462) |
| Revision | Rev A |
Performance
Speed
Pinout
Pin map and connections
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | VBUS | Power | 5V |
| 2 | 3V3 | Power | 300mA spare |
| 3 | GND | Ground | Ground |
| 4 | SDA | I²C | I²C data |
| 5 | SCL | I²C | I²C clock |
| 6 | TX | UART | UART out |
| 7 | RX | UART | UART in |
| 8 | GP0 | Signal | GPIO |
| 9 | GP1 | Signal | GPIO / ADC1 |
| 10 | GP2 | Signal | GPIO / ADC2 / DAC |
| 11 | GP3 | Signal | GPIO / ADC3 / DAC |
Qwiic / STEMMA QT pins: GND, VIN, SDA, SCL (same on both connectors).
Mechanical
Dimensions and what's in the box
In the box
- 1 × ET-C12 USB-C to I²C / Qwiic Adapter (assembled)
- 1 × 11-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
Compare
Which USB adapter?
| USB-C to I²C / Qwiic Adapter (this board)This board | ET-C13 CP2102N USB-UART Adapter | ET-C20 CH340C USB-UART Adapter 5 V | ET-C03 USB-C to UART Adapter | |
|---|---|---|---|---|
| What it does | Talk to Qwiic sensors from a PC — no driver needed | 3 Mbps USB-C serial adapter with flow control, 3.3 V | 5 V logic USB-C serial with Arduino auto-reset | CH340C serial adapter with 3.3 V logic |
| Interface | — | — | — | — |
| Best for | Testing sensors from Python | Flashing ESP32 and STM32 | Programming Arduino Pro Mini | Debug consoles |
| Price | 20 AED | 19 AED | 49 AED | 27 AED |
Downloads
Documents and design files
Need a custom version of this board?
Different connector, size or sensor? We design and build custom variants.