Metro M4 Express

by Adafruit

Image of Board

The most powerful Metro at this time, the Adafruit Metro M4 featuring the Microchip ATSAMD51. This Metro is like a bullet train, with it’s 120MHz Cortex M4 with floating point support. Your code will zig and zag and zoom, and with a bunch of extra peripherals for support, this will for sure be your favorite new chipset.

To start off the ATSAMD51 journey it has a classic ‘Arduino compatible’ shape and pinout. This Metro is the same size as the others, and is compatible with many shields. It’s got analog pins where you expect, and SPI/UART/I2C hardware support in the same spot as the Metro 328 and M0. But! It’s powered with an ATSAMD51J19:

  • Cortex M4 core running at 120 MHz
  • Floating point support with Cortex M4 DSP instructions
  • 512 KB flash, 192 KB RAM
  • 32-bit, 3.3V logic and power
  • Dual 1 MSPS DAC (A0 and A1)
  • Dual 1 MSPS ADC (8 analog pins)
  • 6 x hardware SERCOM (I2C, SPI or UART)
  • 22 x PWM outputs
  • Stereo I2S input/output with MCK pin
  • 64 QFN

Includes:

  • Power the METRO M4 with 7-9V polarity protected DC or the micro USB connector to any 5V USB source. The 2.1mm DC jack has an on/off switch next to it so you can turn off your setup easily. The METRO will automagically switch between USB and DC.
  • METRO has 25 GPIO pins, 8 of which are analog in, and two of which is a true analog out. There’s a hardware SPI port, hardware I2C port and hardware UART. Logic level is 3.3V
  • Native USB, there’s no need for a hardware USB to Serial converter as the Metro M4 has built in USB support. When used to act like a serial device, the USB interface can be used by any computer to listen/send data to the METRO, and can also be used to launch and update code via the bootloader. It can also act like an HID keyboard or mouse.
  • Four indicator LEDs and one NeoPixel, on the front edge of the PCB, for easy debugging. One green power LED, two RX/TX LEDs for data being sent over USB, and a red LED connected. Next to the reset button there is an RGB NeoPixel that can be used for any purpose.
  • 2 MB QSPI Flash storage chip is included on board. You can use the SPI Flash storage like a very tiny hard drive. When used in Circuit Python, the 2 MB flash acts as storage for all your scripts, libraries and files.
  • Easy reprogramming, comes pre-loaded with the UF2 bootloader, which looks like a USB storage key. Simply drag firmware on to program, no special tools or drivers needed! It can be used to load up CircuitPython (it is bossa v1.8 compatible)

The primary target for this board is CircuitPython - with 120 MHz, and 192KB of RAM CircuitPython runs really well on this chip. At this time, the latest versions of CircuitPython working on this board, and more API parts are added every week.

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CircuitPython 4.1.0

This is the latest stable release of CircuitPython that will work with the Metro M4 Express.

Start here if you are new to CircuitPython.

Release Notes for 4.1.0

CircuitPython 5.0.0-alpha.4

This is the latest unstable release of CircuitPython that will work with the Metro M4 Express.

Unstable builds have the latest features but are more likely to have critical bugs.

Release Notes for 5.0.0-alpha.4

Absolute Newest

Every time we commit new code to CircuitPython we automatically build binaries for it. They are stored on Amazon S3 by language (some which may be unreleased.) Try them if you want the absolute latest and are feeling risky.

Past Releases

All previous releases are available on GitHub. They are handy for testing but we recommend the latest stable otherwise.