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SparkFun Thing Plus - SAMD51

Is it power you seek? With a 32-bit ARM Cortex-M4F MCU, the SparkFun SAMD51 Thing Plus is one of our most powerful microcontroller boards yet! The SAMD51 Thing Plus provides you with an economical and easy to use development platform if you're needing more power with minimal working space. This Thing even comes flashed with the same convenient UF2 bootloader as the RedBoard Turbo. To make the Thing Plus even easier to use, we've moved a few pins around to make the board Feather compatible and it utilizes our handy Qwiic Connect System which means no soldering or shields are required to connect it to the rest of your system!

The ATSAMD51J20 utilizes a 32-bit ARM Cortex-M4 processor with Floating Point Unit (FPU), running up to 120MHz, up to 1MB of flash memory, up to 256KB of SRAM with ECC, up to 6 SERCOM interfaces, and other features. In addition to the USB interface and Qwiic connection, a The SAMD51 Thing Plus provides a 600mA 3.3V regulator and LiPo charger.

The SparkFun Qwiic Connect System is an ecosystem of I2C sensors, actuators, shields and cables that make prototyping faster and less prone to error. All Qwiic-enabled boards use a common 1mm pitch, 4-pin JST connector. This reduces the amount of required PCB space, and polarized connections mean you can’t hook it up wrong.

  • ATSAMD51J20 microcontroller
    • 32-bit ARM Cortex-M4F MCU
    • Up to 120MHz CPU speed
    • 1MB flash memory
    • 256KB SRAM
    • Up to 6 SERCOM interfaces
  • UF2 bootloader
  • Qwiic connector
  • USB interface for programming and power
  • 600mA 3.3V regulator
  • 4Mb (external) flash memory
  • LiPo charger
  • Feather pin layout

SparkFun Thing Plus - SAMD51 Product Help and Resources

Adding More SERCOM Ports for SAMD Boards

February 4, 2019

How to setup extra SPI, UART, and I2C serial ports on a SAMD-based boards.

SAMD51 Thing Plus Hookup Guide

May 24, 2019

This tutorial covers the basic functionality of the SAMD51 Thing Plus and highlights the features of the new ARM Cortex-M4F development board.

ARM Programming

May 23, 2019

How to program SAMD21 or SAMD51 boards (or other ARM processors).

SparkFun Qwiic Shield for Thing Plus Hookup Guide

January 30, 2020

A short guide for assembling and using the SparkFun Qwiic Shield for Thing Plus.

Core Skill: Programming

If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.

2 Programming

Skill Level: Rookie - You will need a better fundamental understand of what code is, and how it works. You will be using beginner-level software and development tools like Arduino. You will be dealing directly with code, but numerous examples and libraries are available. Sensors or shields will communicate with serial or TTL.
See all skill levels

Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

2 Electrical Prototyping

Skill Level: Rookie - You may be required to know a bit more about the component, such as orientation, or how to hook it up, in addition to power requirements. You will need to understand polarized components.
See all skill levels


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • But how is this a part of Internet of THINGs if it doesn't have WiFi?

  • External flash memory is way-smaller than advertised! The included Adesto AT25SF041 serial flash is only 512KB, but your "Hookup Guide" and the "Hardware Overview" advertises flash size as 4MB, this is incorrect, actual size is 512KB (or 4Mbit).

    Please note error in documentation.

  • Looks like the graphical data sheet is broken (nine of the labels are showing up).

  • Is it possible to run TensorFlow Lite in SparkFun Thing Plus - SAMD51?

  • How do I access the memory to store data?

  • Just discovered this board. Looks really interesting, though a couple of issues 1) It can't measure the voltage on the LiIon 2) I can't hook up an external Vref. Great to see the LiIon chg at 0.5A (though be areally to manage it based on USB(C) connection), 4M flash Eeprom.

  • It looks like the only way to access the SWDIO and SWCLK signals is through a small surface mount test point. That would seem to make this board a no-go for anyone wanting to develop on it and use a debugger like a JLink, STlink, BlackMagic Probe, etc.

  • @Santa Claus Impersonator: Thanks for fixing the documentation links. There are still several points of confusion for me as a new user of this board. The chip has so much flexibility it leaves me somewhat muddled. Programming through the Linux version of the Arduino IDE (1.89) using the default variant.cpp file it seems that the async port known as 'Serial1' corresponds to the D1 & D0 pins. The compiler does not recognize 'SerialUSB' as on the SAMD21 Pro RF, but opening & writing to just 'Serial' appears to send output to the onboard USB connector which appears in Linux as some variant of /dev/ttyACM[x]. Is this correct?

    • It sounds like you might be looking for technical assistance. Please use the link in the banner above, to get started with posting a topic in our forums. Our technical support team will do their best to assist you.

      Otherwise, that is correct, Serial1 refers to the the hardware pin serial connection and Serial refers to the USB connection. In the Arduino IDE, the built-in Examples>Communication>SerialPassthrough example explains it more clearly. It depends on your flavor of Linux for the name of the serial port, but yes... any information on Serial should pass through the USB connection of the computer and is what you would normally interact with through the Serial Monitor of the Arduino IDE.

  • Where is the datasheet and the Graphical datasheet? Links: https://cdn.sparkfun.com/assets/c/a/8/6/8/ThingPlusSamD51a.pdf and https://cdn.sparkfun.com/assets/0/0/5/9/2/60001507C.pdf are dead as rocks!

  • Nice board! Love the Feather compatibility. But it seems even harder for old fingers to get the bootloader right than the SAMD21's!

  • amazing little board!!

  • I started to checkout, but when i got to the shipping prices... Holy cow, its messed up. Ok, so if i wanted to choose 3-11, that price is fair. But what a gap in time. 1-5, so i could pay more, but the 3-11 days falls within 1-5. makes no sense. 2 day is $21 & next is $28. Are those prices for the rich and famous only? For how much product you ship, you should really have a better strategy laid out.

    Next Business Day $28.96 2 Business Days $21.88 1-5 Business Days $13.36\ 3-11 Business Days $6.67

    • Thank you for your feedback, we are constantly working to get better shipping prices and improve customer experience. As for the 1-5 vs the 3-11, those are 2 different methods as defined by FedEx, we've just chosen to not list them by name but by time frame which makes more sense to people, but I understand how it can be confusing. I will pass along your concerns and thanks again for your feedback.

  • Link to the Hookup Guide is broken. 404 error

  • Description says 6 SERCOMs, Features says 8, and the video says 8. Which is correct?

  • Is it really an 8-bit AVR microcontroller? It says that it's a 32-bit ARM, and searching for AVR in the datasheet returns no hits.

    Also, the link to the hookup guide leads to a 404 site.

  • This seems like a bad deal on all fronts compared with the ESP32 Thing, which has more memory/storage and WiFi and BTLE, at the same price. (Also, how can you call this an “8-bit AVR microcontroller” when it has a 32-bit ARM CPU?)

Customer Reviews

4.5 out of 5

Based on 2 ratings:

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1 of 1 found this helpful:

solid design...stable bootloader

so far...using mac based arduino system...it has been more stable than some adafruit boards...looks like a good "brain" for my design of networked "pods" in a machine design...

Nice toy but...

I managed to toast my first SAMD51 by connecting a battery with a wrong polarization (smokin.... literally). Apart from that a fun toy. Sometimes a bit hard to find suitable libs for some corner cases. General lib coverage is, however, very good.