ATSAMD21-XPRO - SAM D21 Xplained Pro ARM Cortex-M0+ Eval Board
MPN: ATSAMD21-XPRO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $43.74 | $43.74 |
| 10 | $42.1 | $421.00 |
| 25 | $40.55 | $1,013.75 |
| 50 | $38.9 | $1,945.00 |
| 100 | $36.25 | $3,625.00 |
ATSAMD21-XPRO Overview
An evaluation board is a printed circuit assembly built around a target microcontroller or SoC, used by hardware and firmware engineers to prototype firmware, validate power and clock trees, and exercise on-chip peripherals before committing to a custom PCB. The ATSAMD21-XPRO belongs to Microchip's Xplained Pro family of evaluation kits, which share a standardized 20-pin extension header and Atmel/Microchip Studio IDE workflow, accelerating project bring-up and reducing prototype hardware risk.
Key features include USB-powered operation via the Micro-B connector, an integrated CMSIS-DAP debug interface that exposes a virtual COM port for serial debugging, two 32.768 kHz and 12 MHz crystals, and an ATECC608A-compatible footprint for optional secure element add-on. The board is supported by Microchip's MPLAB X IDE, Atmel Studio 7, and the web-based Atmel START configuration tool. The Arduino Uno-compatible header footprint allows access to specific SAM D21 pins for shield prototyping.
The on-board ATSAMD21J18A SoC integrates a 6-channel SERCOM peripheral, a 14-channel event system, a 12-bit ADC/DAC, and a full-speed USB 2.0 device/host controller. These resources make the ATSAMD21-XPRO suitable for sensor fusion, USB HID/CDC prototypes, low-power battery-driven nodes, and consumer wearables. The integrated nEDBG debugger eliminates the need for an external JTAG/SWD probe, lowering the total bill of materials for early development.
Typical applications include IoT edge node firmware bring-up, USB device class prototyping (HID, CDC, MSD), low-power sensor data logger evaluation, hobbyist Arduino-alternative projects, and pre-production hardware validation. Designers evaluating the SAMD21 silicon for mass-production designs commonly use this board to verify peripheral drivers, FreeRTOS porting, and Asleep state current budgets before laying out a custom PCB.
When designing with the ATSAMD21-XPRO, note that the nEDBG USB port and the target ATSAMD21J18A USB port are separate physical interfaces - the nEDBG supplies power and debug, while the target USB exposes the SAMD21 native USB peripheral. Do not populate both USB connections simultaneously in a powered hub without managing VBUS arbitration, otherwise upstream current draw can exceed the 500 mA USB spec.
Drop-in alternatives for ATSAMD21-XPRO — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ATSAMD21-XPRO (same form factor and footprint) — differing in USB, ADC, Operating Temperature, Package, Core.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD20-XPRO
✅ Drop-In✓ In Stock
$70 / Unit
View Datasheet →ATSAMD21G18A-MF
✅ Drop-In✓ In Stock
$2.65 / Unit
View Datasheet →ATSAMD21J18A-MF
✅ Drop-In✓ In Stock
$3.6 / Unit
View Datasheet →ATSAMD21J18A-CU
✅ Drop-In✓ In Stock
$2.52 / Unit
View Datasheet →ATSAMD21E18A-MF
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$6.95 / Unit
View Datasheet →STM32 Nucleo-F072RB
✅ Drop-In📋 Reference alternative (not in catalog)
NXP LPCXpresso11U68
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMD21-XPRO Specifications (manufacturer-published)
| Product Type | Evaluation Board (Xplained Pro) |
| Target MCU | ATSAMD21J18A |
| Core Processor | ARM Cortex-M0+ 32-bit |
| CPU Max Frequency | 48 MHz |
| Flash Memory (on-chip) | 256 KB |
| SRAM | 32 KB |
| On-board SPI Flash | 1 MB |
| Low-frequency Crystal | 32.768 kHz |
| High-frequency Crystal | 12 MHz |
| Debug Interface | nEDBG (CMSIS-DAP) on-board |
| USB Connectors | 1x Micro-B (debug/CDC), 1x Micro-B (target) |
| Extension Headers | 3x 20-pin Xplained Pro (compatible with I/O1, OLED1, QT1, PROTO1) |
| User Inputs | 1x mechanical reset button, 1x user touch button |
| User Outputs | 1x user LED |
| Arduino-compatible Headers | Yes (subset of ATSAMD21J18A I/O) |
| Operating Voltage (target) | 3.3 V |
| Board Power Source | USB Micro-B |
| Supported IDEs | MPLAB X IDE, Atmel Studio 7, Atmel START |
| RoHS Status | Compliant |
| Form Factor | Xplained Pro standard (approx 88 mm x 53 mm) |
ATSAMD21-XPRO Interfaces & Connectors
ATSAMD21-XPRO exposes the following interfaces and connectors as published by the manufacturer: Expansion / Buses, USB. Expansion header pinout, connector pin numbering, and electrical limits are defined in the manufacturer documentation.
| Expansion / Buses | 1 MB |
| USB | 1x Micro-B (debug/CDC), 1x Micro-B (target) |
Refer to the manufacturer documentation for the full expansion header pinout and connector pin numbering.
Typical Applications
ATSAMD21-XPRO is suitable for 7 applications: IoT Edge Node Firmware Prototyping, USB Device Class Prototyping, Low-Power Sensor Data Logger, Arduino-Shield Compatible Prototyping, Consumer Wearable Proof of Concept, Industrial Sensor Hub Validation, Pre-Production Hardware Validation.
IoT Edge Node Firmware Prototyping
The ATSAMD21-XPRO is a strong fit for IoT edge node firmware prototyping because its on-board ATSAMD21J18A integrates a 48 MHz Cortex-M0+ core, six SERCOM channels for SPI/I2C/UART, a 12-bit ADC with up to 16 channels, and a full-speed USB 2.0 controller - covering the radio, sensor, and backhaul interfaces a typical edge node needs. The board's low-power Sleep mode draws roughly 5 uA on the 3.3 V rail, allowing engineers to characterise battery-life budgets for coin-cell or LiPo powered sensor nodes. The 256 KB Flash and 32 KB SRAM accommodate Over-The-Air (OTA) bootloader, application code, and TLS stacks without external memory. The integrated nEDBG debugger exposes a virtual COM port so a serial console and firmware flashing share a single USB cable, simplifying the bench.
Recommended
USB Device Class Prototyping
Engineers prototyping USB HID, CDC, or MSD class devices benefit from the ATSAMD21-XPRO's two independent USB Micro-B ports: one feeds the nEDBG debugger for power and serial console, the other connects to the ATSAMD21J18A's native USB 2.0 full-speed device/host controller. This lets a developer exercise USB enumeration, suspend/resume, and remote-wakeup behaviour without external hub complexity. The 256 KB Flash comfortably fits USB stacks like LUFA or TinyUSB along with application code, while 32 KB SRAM buffers CDC data streams without dropping packets. The standardized Arduino-compatible subset header provides easy breakout to external USB Type-A receptacles, downstream hubs, or bus-powered peripherals during validation.
Recommended
Low-Power Sensor Data Logger
The ATSAMD21-XPRO suits battery-powered sensor data logger development because the ATSAMD21J18A silicon supports multiple Sleep modes with RAM retention down to approximately 5 uA core current, while the on-board 1 MB SPI Flash (Macronix MX25R) provides weeks of buffered sensor data even when the host is offline. The board's three Xplained Pro extension headers accommodate the I/O1 Xplained Pro sensor board or the OLED1 Xplained Pro display board for quick bring-up. The integrated 12-bit ADC at up to 350 ksps and the 32.768 kHz crystal enable RTC-driven wake-up cycles accurate to within a few seconds per day. Engineers use the ATSAMD21-XPRO to benchmark their power-management code before laying out custom logger PCBs.
Recommended
Arduino-Shield Compatible Prototyping
The ATSAMD21-XPRO exposes an Arduino-Uno-compatible subset header that brings out the ATSAMD21J18A's I/O, 3.3 V power, and reset lines so engineers can drop in third-party Arduino shields for rapid prototyping. Compared to the Arduino Zero - which uses the same silicon family - the XPRO adds three standardized Xplained Pro extension headers, an onboard debugger, and a 1 MB external SPI Flash, accelerating both development and field debugging. The 48 MHz Cortex-M0+ core outperforms 8-bit AVR boards by roughly an order of magnitude in Dhrystone while preserving the Arduino toolchain via the Arduino SAMD core. This combination makes the XPRO attractive for educational labs migrating from AVR to 32-bit ARM Cortex-M0+.
Recommended
Consumer Wearable Proof of Concept
Wearables and fitness-tracker designers use the ATSAMD21-XPRO to validate firmware concepts because the ATSAMD21J18A silicon integrates a 14-channel event system, six SERCOM peripherals, a capacitive touch controller, and a 12-bit ADC plus DAC - the building blocks for fitness bands and smart watches. The ATSAMD21-XPRO's 1.8 V to 3.6 V supply range matches coin-cell operation, and the on-board 32.768 kHz crystal feeds a low-power RTC that wakes the core on a schedule without burdening the main oscillator. The board's USB Micro-B port allows tethered charging emulation while firmware iteration proceeds. Once the firmware stabilises, designs migrate to the ATSAMD21E18A-MF 32-pin QFN, halving the PCB area.
Recommended
Industrial Sensor Hub Validation
Industrial sensor hub prototypes built on the ATSAMD21-XPRO leverage the on-board ATSAMD21J18A's six SERCOM channels, which can simultaneously host SPI sensors (e.g., accelerometers), I2C sensors (e.g., temperature/pressure ICs), and UART links to a wireless module or industrial bus gateway. The 256 KB Flash accommodates Modbus RTU or CANopen protocol stacks alongside sensor drivers, while the 12-bit ADC supports 4-20 mA loop current sensing for legacy industrial transducers. The standardized Xplained Pro OLED1 extension header can drive a local display for diagnostics in field-deployed hub prototypes. Engineers developing industrial IoT gateways commonly use the ATSAMD21-XPRO as a hardware reference before designing their own carrier PCB around the ATSAMD21J18A silicon.
Recommended
Pre-Production Hardware Validation
Hardware validation engineers use the ATSAMD21-XPRO to qualify a custom carrier PCB built around the ATSAMD21J18A silicon before mass production. The Xplained Pro board's onboard nEDBG debugger can connect to the target board's SWD header via ribbon cable, allowing firmware flashing and boundary-scan debugging of a custom PCB that lacks its own debugger. Engineers write firmware against the XPRO first, then validate that the same firmware runs correctly on their custom board, catching clock-tree, decoupling, and pin-mux issues early in the validation cycle. The board's user LED and user touch button provide simple HMI feedback during smoke testing.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21-XPRO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD20-XPRO | ATSAMD21G18A-MF | ATSAMD21J18A-MF | STM32 Nucleo-F072RB | NXP LPCXpresso11U68 |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | STMicroelectronics | NXP Semiconductors |
| Package / Form Factor | Xplained Pro eval board (88 mm x 53 mm) | Xplained Pro eval board (same) | QFN-48 silicon | QFN-64 silicon (same MCU as on-board) | Arduino-Nucleo eval board | LPCXpresso eval board |
| Target MCU | ATSAMD21J18A (Cortex-M0+) | ATSAMD20J18A (Cortex-M0+) | ATSAMD21G18A (Cortex-M0+) | ATSAMD21J18A (Cortex-M0+ - identical) | STM32F072RBT6 (Cortex-M0) | LPC11U68 (Cortex-M0+) |
| Core / Frequency | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0 @ 48 MHz | ARM Cortex-M0+ @ 50 MHz |
| Flash / SRAM | 256 KB / 32 KB | 256 KB / 32 KB | 256 KB / 32 KB | 256 KB / 32 KB | 128 KB / 16 KB | 256 KB / 36 KB |
| Onboard Debugger | nEDBG CMSIS-DAP | nEDBG CMSIS-DAP (same) | Silicon only (no eval board) | Silicon only (no eval board) | ST-Link/V2-1 | LPC-Link2 CMSIS-DAP |
| USB 2.0 Support | Full-speed device/host | None (SAM D20 lacks USB) | Full-speed device/host (yes) | Full-speed device/host (yes) | Full-speed device (yes) | Full-speed device/host (yes) |
| Extension Headers | 3x Xplained Pro 20-pin | 3x Xplained Pro 20-pin (same) | N/A (silicon) | N/A (silicon) | Arduino Uno R3 + Morpho | Arduino Uno R3 headers |
| Typical Unit Price (1 pc) | USD 43.74 | USD 41-43 (similar) | USD 3-4 (silicon unit) | USD 4-5 (silicon unit) | USD 15-17 | USD 20-25 |
Key Differentiators
- Integrated nEDBG debugger eliminates external probe cost (vs Arduino Zero)
- Three standardized Xplained Pro extension headers (vs Adafruit Feather M0)
- On-board 1 MB external SPI Flash for data buffering (vs STM32 Nucleo-F072RB)
Design Notes
Power the ATSAMD21-XPRO only through the nEDBG Micro-B connector for typical development; the target USB Micro-B port feeds the ATSAMD21J18A's native USB peripheral directly. Avoid powering both ports simultaneously from separate hosts, otherwise VBUS back-powering can occur. The on-board 3.3 V LDO supplies up to 500 mA to the target MCU and extension headers; budget roughly 100 mA for the MCU + nEDBG, leaving ~400 mA for extension boards before exceeding USB 2.0 spec.
When migrating from the ATSAMD21-XPRO to a custom PCB, copy the decoupling scheme: place a 100 nF X7R 0402 capacitor within 2 mm of each AVDD/VDD pin pair, add a 4.7 uF bulk capacitor near the regulator output, and route the 32.768 kHz crystal within 5 mm of the XIN32/XOUT32 pins with a guarded ground plane to keep RTC drift below 50 ppm. The MCU's two VDDIO rails benefit from separate decoupling networks to suppress SERCOM switching noise on the ADC reference.
Do not hot-plug the ATSAMD21-XPRO with extension boards while firmware is running - the Xplained Pro 20-pin connector carries I/O that can be reconfigured mid-execution. Always issue a board reset after attaching OLED1 or I/O1 extensions, because some add-on boards drive I2C lines during their own boot sequence. Additionally, when migrating from the on-board ATSAMD21J18A (64-pin QFN) to the ATSAMD21E18A (32-pin QFN), verify SERCOM pad multiplexing - the 32-pin package restricts peripheral pin assignments and may require firmware rework.
The ATSAMD21J18A's industrial temperature range (-40C to +85C) is comfortably covered by the ATSAMD21-XPRO board without active cooling. The four-layer PCB provides sufficient copper pour for the moderate 7 mA active and 5 uA sleep currents typical of edge-node applications. For firmware that spends significant time in active 48 MHz mode, expect roughly 200 mW dissipation - well within the board's thermal envelope, but do not seal the XPRO in an enclosed housing without providing airflow or a heatsink tab on the QFN's exposed pad.
Compliance Information
RoHS and REACH compliance per Microchip product environmental disclosures. Lead-free assembly. Halogen-free status not explicitly disclosed for the eval board; refer to Microchip environmental compliance page for further detail. AEC-Q100 not applicable - this is a development tool, not an automotive-grade silicon.