SparkFun RedBoard Turbo - SAMD21 Development Board

If you’re ready to step up your Arduino game from older 8-bit/16MHz microcontrollers, the SparkFun RedBoard Turbo is a formidable alternative. At its heart, the RedBoard Turbo uses the ATSAMD21G18, which is an ARM Cortex M0+, 32-bit microcontroller that can run at up to 48MHz. With an impressive 4MB of external flash memory and a UF2 (USB Flashing Format) bootloader, the RedBoard Turbo provides you with an economical and easy to use development platform if you're needing more power than the classic RedBoard.

The SparkFun RedBoard Turbo has been equipped with a USB interface for programming and power, a Qwiic connector, an RTC crystal, WS2812-based addressable RGB LED, 600mA 3.3V regulator, and a variety of other components. To power the RedBoard Turbo, just plug it into a USB port on your computer via the micro-B port or directly into the wall with the 5V tolerant barrel jack. Not near a USB port? No problem, the SparkFun RedBoard Turbo is also equipped with a LiPo Battery connector (for a single-cell 3.7-4.2V litium-polymer battery). The MCP73831's charge current is configured by a resistor value between 66kΩ and 2kΩ, to charge the battery at a rate between 15mA and 500mA, respectively. By default, the board is configured to charge the battery at around 250mA. If you’ve used any Arduino before, this pinout shouldn’t surprise you – the layout meets the Arduino 1.0 footprint standard, including a separate SPI header and additional I2C header.

The RedBoard Turbo can even be flashed over the Mass Storage Class (MSC) just like a removable flash drive, thanks the the UF2 bootloader. With this bootloader, the RedBoard Turbo shows up on your computer as a USB storage device without having to install drivers! From the Arduino IDE, you’ll still need to select the correct port on your machine, but you can just as easily use another programming language such as CircuitPython or MakeCode.

Note: The barrel jack connection on the RedBoard Turbo has a lower input voltage than most Arduino development boards. Make sure that you are using a power supply below 6V. Please be aware that the RedBoard Turbo is also a 3.3V device and not a 5V one like the original RedBoard.

  • ATSAMD21G18 32-bit/48MHz ARM Cortex-M0+
  • 4MB Flash Memory
  • 32KB SRAM
  • 32KB of EEPROM (emulated in Flash)
  • 26 GPIO Count
  • 14 ADC Channels at 12-bit Resolution
  • Analog-to-Digital and Digital-to-Analog Converters (ADC & DAC)
  • Vin: 4.2V-6.0V for charger - otherwise 3.5V-6.0V
  • VBATT: 3.7V Lipo
  • VCC: 600mA @3.3V
  • Arduino R3 Layout
  • Integrated USB Controller
  • UF2 Bootloader
  • Qwiic Connector

SparkFun RedBoard Turbo - SAMD21 Development Board Product Help and Resources

Keyboard Shortcut, Qwiic Keypad

April 25, 2019

A simple project using the Qwiic Keypad and the RedBoard Turbo to create your own custom hotkey-pad.

ARM Programming

May 23, 2019

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

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.

RedBoard Turbo Hookup Guide

January 24, 2019

An introduction to the RedBoard Turbo. Level up your Arduino-skills with the powerful SAMD21 ARM Cortex M0+ processor!

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.

  • Nice board especially the price. I suspect a lot of folks may start to use it instead of the UNO. A word to the wise if you plug in your favorite UNO shield that is populated with an ISP header, Shields such as the proto shield DEV-1382/13819 and the microSD shield dev-12761, the 3.3volts will be shunted to the 5.0v USB supply.There are several ways around this but if you don't wish to cut board traces you can pull the 5.0v pin from the shield's ISP stackable header. As a side note the ISP header connections are not documented on the schematic for this board. This is also the case for the case for the SAMD21 Dev Breakout (DEV-13672 ). This information is available on the graphical data sheet and the eagle files.

  • A 32-bit ARM Arduino-like board, with built-in battery management and bonus flash storage, for (slightly) under $25? And from a non-shady vendor like SparkFun who supports their stuff? Very, very cool.

  • Some random things I have noticed when using this board:

    On a Mac, make sure you are using a quality USB cable, or you will have difficulty getting the USB port to show up in the Arduino IDE. At least that has been my experience. This is not unique to this board with Macs.

    If you are connecting this to a Pixy2, you will have to modify the Pixy2 library and replace references to the "Serial" object with "SerialUSB". I had to modify Pixy2.h, Pixy2CCC.h and TPixy2.h in this way. I also had to remove the ZumoBuzzer.cpp from the library in order to compile my sketch. I don't have a Zumo robot, so I didn't bother debugging the issue.

    • After modifying many libraries and pulling my hair out I found a quick solution, start your sketch with "#Define Serial SerialUSB" (before all the other library calls) to map the SerialUSB to Serial - then any standard AVR arduino libraries will work with the turbo without modification. I've written code that will work on either board flavor by just commenting or uncommenting that snippet.

  • Does the new board allow the user to turn off that insanely bright power LED? (Yes I know I can put tape over it, but it's still using power). Other than that, I love my original Redboard.

    • There is a cuttable trace for the power LED.

      But, if the schematic is to be believed, we're back to 330Ω resistors on the LEDs. The other current RedBoards have transitioned to 4.7kΩ, much easier on the eyes (and batteries!)

  • I see a debugging socket on the board (unpopulated). What is the pitch of the socket? What debugger does that require? Also, if I load my own code through the debugging socket, does that invalidate the UF2 bootloader, or can it still be used?


    • Those pins are for SWD; they are 50 (not 15... see reply below) mil pitch. In production, we use an Atmel-ICE programmer. You can use any similar product as long as it is AVR/SAMD compatible. As with all programmers, you are flashing the microcontroller... so yes, the bootloader would get overwritten. However, the bootloader is available in the Firmware folder of the GitHub repository if you need.

Customer Reviews

4 out of 5

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1 of 1 found this helpful:

Nice Board. Arduino Library issue.

Just starting to use the board. I'm working on a problem with connecting a shifting uSD breakout board. After updating an SD library example sketch for the Serial port name change, I found that the standard SD library has some Serial.print statement embedded. A couple src/utilities/~.cpp files have these Serial.print statements embedded. This could get complicated if other libraries do the same. Otherwise the board is performing as advertised. The hookup guide is quite accurate and complete and excellent for getting up and going.

I bought this by mistake

I was buying a Lightning Detector and thought I would try a Sparkfun RedBoard to connect it with but I accidentally selected the wrong board. I thought I would run with it but I could not get my computer to offer me a port to connect it to. My distribution is Debian GNU/Linux 8 (jessie), and I have a Lenova laptop. I tried in both the USB 2 and 3 ports but no use. Eventually I gave up and ordered a ordinary RedBoard. Because Sparkfun do not give a USPS option to deliver goods I knew that the delivery would take a long time as the delivery company you use hold any item that is sent without express delivery for several days to make their express service look good, so while I was waiting I obtained a Arduino Uno and used that instead.That worked fine. The moral is that Sparkfun should offer a USPS option to deliver items. The Arduino board came by ordinary post in 4 days as opposed to 11 days from Sparkfun. Irwin Hutchinson