ET-M05
CH32V003 RISC-V Qwiic MCU
Tiny 48 MHz RISC-V MCU that runs from 3.3 or 5 V Qwiic
AED 9.00
Out of stockOverview
Tiny 48 MHz RISC-V MCU that runs from 3.3 or 5 V Qwiic
The ET-M05 is built around the WCH CH32V003 — 32-bit RISC-V2A 48MHz, 16KB flash, 2KB SRAM, 10-bit ADC, op-amp, USART/I2C/SPI. It runs from Runs directly from Qwiic/VIN 3.3V or 5V (2.7–5.5V).
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 I²C peripherals
- Cheap smart helpers inside projects
- Learning RISC-V bare metal
Key features
What makes it different
MCU
WCH CH32V003: 32-bit RISC-V2A 48MHz, 16KB flash, 2KB SRAM, 10-bit ADC, op-amp, USART/I2C/SPI
Supply
Runs directly from Qwiic/VIN 3.3V or 5V (2.7–5.5V)
Programming
1-wire SWIO (WCH-LinkE) on J4
I/O
9 GPIO + I2C on the header; can act as a custom I2C peripheral on the Qwiic bus
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
| MCU | WCH CH32V003: 32-bit RISC-V2A 48MHz, 16KB flash, 2KB SRAM, 10-bit ADC, op-amp, USART/I2C/SPI |
|---|---|
| Supply | Runs directly from Qwiic/VIN 3.3V or 5V (2.7–5.5V) |
| Programming | 1-wire SWIO (WCH-LinkE) on J4 |
| I/O | 9 GPIO + I2C on the header; can act as a custom I2C peripheral on the Qwiic bus |
| 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) · 13-pin 2.54 mm header |
| Main IC | CH32V003F4U6 (LCSC C5299908) |
| Revision | Rev A |
| Libraries | ch32v003fun, WCH MounRiver/OpenWCH SDK, Arduino core (openwch/arduino_core_ch32) |
|---|
| JP1 (default Closed) | Cut to turn off the LED |
|---|---|
| JP2 (default Closed) | Cut to remove the host-side I2C pull-ups |
Performance
Memory
Pinout
Pin map and connections
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | VIN | Power | Sensor supply = host logic level |
| 2 | GND | Ground | Ground |
| 3 | SCL | I²C | I²C clock |
| 4 | SDA | I²C | I²C data |
| 5 | PA1 | GPIO | ADC A1 |
| 6 | PA2 | GPIO | ADC A0 |
| 7 | PC0 | GPIO | GPIO |
| 8 | PC3 | GPIO | GPIO/PWM |
| 9 | PC4 | GPIO | ADC A2, PWM |
| 10 | PD4 | GPIO | ADC A7 |
| 11 | PD5 | GPIO | UART TX |
| 12 | PD6 | GPIO | UART RX |
| 13 | NRST | Control | Reset |
Qwiic / STEMMA QT pins: GND, VIN, SDA, SCL (same on both connectors). I²C pull-ups (10 kΩ) are on the board; cut JP2 to remove them.
Mechanical
Dimensions and what's in the box
In the box
- 1 × ET-M05 CH32V003 RISC-V Qwiic MCU (assembled)
- 1 × 13-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: ch32v003fun, WCH MounRiver/OpenWCH SDK, Arduino core (openwch/arduino_core_ch32)
Compare
Which small MCU for a Qwiic helper?
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|---|---|---|---|---|
| What it does | Tiny 48 MHz RISC-V MCU that runs from 3.3 or 5 V Qwiic | Cortex-M0+ 64 MHz with SWD and level-shifted Qwiic | 20 MHz tinyAVR with UPDI, 3.3–5 V, Qwiic | Dual-core 133 MHz, 2 MB flash, PIO, USB-C and Qwiic |
| Interface | — | — | — | — |
| Best for | Custom I²C peripherals | Learning STM32 HAL and Rust embassy | Arduino-programmable I²C helpers | PIO tricks: WS2812, VGA, extra UARTs |
| Price | 9 AED | 39 AED | 15 AED | 29 AED |
Downloads
Documents and design files
Need a custom version of this board?
Different connector, size or sensor? We design and build custom variants.