Metro M4 Express
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
- 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.
Have some info to add for this board? Edit the source for this page here.
This is the latest stable release of CircuitPython that will work with the Metro M4 Express.
Start here if you are new to CircuitPython.
Built-in modules available: _bleio, adafruit_bus_device, adafruit_pixelbuf, aesio, analogio, atexit, audiobusio, audiocore, audioio, audiomixer, audiomp3, binascii, bitbangio, bitmaptools, board, busio, countio, digitalio, displayio, errno, fontio, framebufferio, frequencyio, getpass, i2cperipheral, json, keypad, math, microcontroller, msgpack, neopixel_write, nvm, onewireio, os, paralleldisplay, ps2io, pulseio, pwmio, rainbowio, random, re, rgbmatrix, rotaryio, rtc, sdcardio, sharpdisplay, storage, struct, supervisor, synthio, terminalio, time, touchio, traceback, ulab, usb_cdc, usb_hid, usb_midi, vectorio
Every time we commit new code to CircuitPython we automatically build binaries for each board and language. The binaries are stored on Amazon S3, organized by board, and then by language. Try them if you want the absolute latest and are feeling daring or want to see if a problem has been fixed.
All previous releases are listed on GitHub, with release notes, and are available for download from Amazon S3. They are handy for testing, but otherwise we recommend using the latest stable release. Some older GitHub release pages include the same binaries for downloading. But we have discontinued including binaries as assets on newer release pages because of the large number of files for each release.
Update UF2 Bootloader
Latest version: v3.13.0
The bootloader allows you to load CircuitPython, MakeCode, and Arduino programs. The bootloader is not CircuitPython. You can check the current version of your bootloader by looking in the INFO_UF2.TXT file when the BOOT drive is visible (FEATHERBOOT, CPLAYBOOT, etc.).
It is not necessary to update your bootloader if it is working fine. Read the release notes on GitHub to see what has been changed. In general, we recommend you not update the bootloader unless you know there is a problem with it or a support person has asked you to try updating it.
To update, first save the contents of CIRCUITPY, just in case. Then double-click the reset button to show the BOOT drive. Drag the update-bootloader .uf2 file to the BOOT drive. Wait a few tens of seconds for the bootloader to update; the BOOT drive will reappear. After you update, check INFO_UF2.TXT to verify that the bootloader version has been updated. Then you will need to reload CircuitPython.