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SAMD21 Mini Board

ET-M15

SAMD21 Mini Board

48 MHz Cortex-M0+ with native USB, DAC and Qwiic

AED 23.00

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Download datasheet (PDF)

OverviewKey featuresSpecificationsPerformancePinout

Overview

48 MHz Cortex-M0+ with native USB, DAC and Qwiic

The ET-M15 is built around the Microchip ATSAMD21E18A — Cortex-M0+ 48MHz, 256KB flash, 32KB RAM, native USB, 10-bit DAC, 12-bit ADC, 6 SERCOMs.

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

  • USB HID devices
  • CircuitPython beginners
  • Audio with the DAC

Key features

What makes it different

MCU

Microchip ATSAMD21E18A: Cortex-M0+ 48MHz, 256KB flash, 32KB RAM, native USB, 10-bit DAC, 12-bit ADC, 6 SERCOMs

USB

USB-C, crystal-less USB (clock recovery); UF2 bootloader installed once over SWD

I/O

16 GPIO on the header, Qwiic at 3.3V, SWD header

Power

5V USB-C → AP2112K 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

Device
MCUMicrochip ATSAMD21E18A: Cortex-M0+ 48MHz, 256KB flash, 32KB RAM, native USB, 10-bit DAC, 12-bit ADC, 6 SERCOMs
USBUSB-C, crystal-less USB (clock recovery); UF2 bootloader installed once over SWD
I/O16 GPIO on the header, Qwiic at 3.3V, SWD header
Power5V USB-C → AP2112K 3.3V
Board
Size45.7 × 25.4 mm
Mounting4 × M2.5 holes, 2.54 mm from each corner
Connectors2 × Qwiic / STEMMA QT (JST SH 4-pin) · 22-pin 2.54 mm header · USB-C 16P receptacle (USB 2.0) — USB-C (power + native USB / bridge)
Main ICATSAMD21E18A-MUT (LCSC C2052801)
RevisionRev A
Software
LibrariesArduino SAMD (Zero / Trinket M0 pinout), CircuitPython, MicroPython, Rust atsamd-hal

Performance

Memory

Flash and RAMFrom the ATSAMD21E18A datasheet.

Pinout

Pin map and connections

SAMD21 Mini Board pinout: VBUS, 3V3, GND, RESET, PA02, PA03, PA04, PA05, PA06, PA07, PA08, PA09, PA10, PA11, PA14, PA15, PA18, PA19, PA22, PA23, SDA, SCL
PinNameTypeFunction
1VBUSPower5V from USB-C
23V3Power600mA LDO
3GNDGroundGround
4RESETControlReset, active low
5PA02GPIOA0 / DAC
6PA03GPIOAREF / A1
7PA04GPIOA2
8PA05GPIOA3
9PA06GPIOA4
10PA07GPIOA5
11PA08GPIOD4 / SERCOM0
12PA09GPIOD3 / SERCOM0
13PA10GPIOD1 TX
14PA11GPIOD0 RX
15PA14GPIOD2
16PA15GPIOD5
17PA18GPIOD10
18PA19GPIOD12
19PA22GPIOD6
20PA23GPIOD7
21SDAI²CPA16 — I²C SDA (Qwiic)
22SCLI²CPA17 — I²C SCL (Qwiic)

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-M15 SAMD21 Mini 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 SAMD (Zero / Trinket M0 pinout), CircuitPython, MicroPython, Rust atsamd-hal

Compare

Which USB microcontroller?

SAMD21 Mini Board (this board)This boardET-M11 STM32F411 Dev BoardET-M12 RP2350 Dev BoardET-M16 CH32V203 RISC-V Board
What it does48 MHz Cortex-M0+ with native USB, DAC and Qwiic100 MHz Cortex-M4F with 512 KB flash, USB-C DFU and QwiicDual Cortex-M33 / RISC-V 150 MHz, 2 MB flash, USB-C, Qwiic144 MHz RISC-V with USB, CAN and 64 KB flash
Interface————
Best forUSB HID devicesDSP and fast control loopsPIO tricks and fast I/OLow-cost USB devices
Price23 AED19 AED49 AED19 AED

Downloads

Documents and design files

PDFET-M15 schematicRev ALCSCATSAMD21E18A-MUT datasheet and stockC2052801
STEP3D modelComing soon

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