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Tiny green circuit board with USB-C connector and pin headers

Seeed Studio

Seeed Studio XIAO SAMD21 Pre-Soldered microcontroller

SKU CH-594B-8C375

Pre-soldered microcontroller board with SAMD21G18 running at 48 MHz, 256 KB flash, 32 KB SRAM, 14 GPIO pins, USB-C, and Arduino, MicroPython, CircuitPython support

  • TypeSensors
  • High-performance ARM Cortex-M0+ running at 48MHz
  • 256KB flash and 32KB SRAM for complex sketches
  • Ultra-compact 21 x 17.5mm form factor fits wearables
  • 14 GPIO pins provide 11 analog and 11 digital channels
  • Pre-soldered headers enable instant breadboard prototyping

Pre-Soldered Microcontroller for Wearables

The Seeed Studio XIAO SAMD21 arrives with headers already fitted, so makers can start coding immediately. It targets hobbyists, students and engineers building compact wearables or sensor nodes who want a breadboard-ready board without soldering work.

Thermals Noise and Power Draw

The SAMD21G18 Cortex-M0+ core runs at up to 48 MHz while drawing only microamp-level current in sleep modes. No active cooling is required, the board stays silent and cool during typical sensing or data-logging tasks.

Bundled Software Compatibility Changes

Pre-loaded Arduino, MicroPython and CircuitPython support lets developers switch languages without re-flashing bootloaders. The extra 32.768 kHz crystal improves timing accuracy for real-time clocks and low-power wake-up routines.

Highlights

  • High-performance ARM Cortex-M0+ running at 48MHz
  • 256KB flash and 32KB SRAM for complex sketches
  • Ultra-compact 21 x 17.5mm form factor fits wearables
  • 14 GPIO pins provide 11 analog and 11 digital channels
  • Pre-soldered headers enable instant breadboard prototyping

Specifications

TypeSensors

Questions about this item

How do I install the XIAO SAMD21 on a breadboard and which pins are analog versus digital?

Plug the pre-soldered board directly into a breadboard; it exposes 14 GPIO pins that provide 11 analog and 11 digital functions plus one I2C, one UART and one SPI interface.

What maintenance will the on-board 32.768 kHz crystal need over time?

The crystal is a passive component with no moving parts and requires no scheduled maintenance or replacement.

At sustained 48 MHz operation what limit appears first — flash endurance or SRAM capacity?

The 256 KB flash is rated for typical MCU write cycles; the 32 KB SRAM limits real-time data buffers before flash wear becomes a concern.

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