miniMetroM0

Description

This is what happens if I mix a Arduino Uno Mini with Adafruit's Metro M0 Express.

For this project I used the original board files of the Adruino Uno Mini. These are published as Altium board file here:http://store.arduino.cc/products/uno-mini-le
And the schematic of Adafruit's Metro M0 Express. These are available as Eagle project here: https://github.com/adafruit/Adafruit-Metro-M0-Express-PCB
The route I took to combine both and add some additional Ideas (like the Stemma-qt/qwicc Connector) was importing both into kicad. At the point this project started I used a nightly 5.99 build of kicad. But switched to 6.0 as it was published during the development, which was mostly done during my christmas vacation.

Details

More to write but here are some key-facts:

Schematic compatible to Adafruit's Metro M0 Express
Same MCU and set-up, so same bbootloader should be usable (bootloader flashing not yet testing due to missing Tag-Connect)
Using Tag connect (or compatible) as space saving solution for the programming header
Added i2C connector in stemma-qt/qwicc Style
Same board shape and size as Arduino Uno Mini
Wanted to use OSH-Park's after-Dark PCBs so only 2-Layers (this was a little bit of challenge)

Will publish all Files once I verified everything. Probably on this github page.

I am also working on a TAG connect compatible programmer cable to get the bootloader on the MCU, will put updates here once it is finished and running, So far only all voltage rails and the Power LED are confirmed working

Project Logs

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Flashing Bootloader and first test
Alex • 02/08/2022 at 19:34 • 2 comments

Flashing the bootloader worked. and at least the on-board Neopixel LED is working correctly
DIY Progarmming Adapter
Alex • 02/07/2022 at 19:33 • 0 comments

I used a footprint compatible to Tag-Connect to program the SAMD21. This is only one time needed to burn the boot loader.

You could use the original our use a DIY attempt. There is alredy a DIY solution by Timon which you could find here: https://github.com/timonsku/oshconnect

This was partly my inspiration for my printed Adapter. I use the same Chinese pogo pins. I was just not happy about having an extra PCB there. The white part should be printable on most hobby SLA printers, although I used it to test JLCPCBs new printing service.

To this it is possible to older some cables and a little 10p SWD break outboard (thisor similar)
With this little board it easy to connect to your Programmer. I used an Atmel ICE for flashing the bootloader from the bigger Metro M0 Express.
Log for more Images
Alex • 02/06/2022 at 21:00 • 0 comments

Rendering of the back made in Kicad:
For refernce the first Tweet about this project.
Alex • 02/06/2022 at 20:52 • 0 comments

https://twitter.com/tinyledmatrix/status/1489645106323988483?s=20&t=bt-DCIdvQbnd1HggcUSvTQ

All Images should be also available here. There should be more Images and Information on this project side.
This Tweet predates this Project but was kind of the starting point
Alex • 02/06/2022 at 20:47 • 0 comments

https://twitter.com/tinyledmatrix/status/1463611566360862727?s=20&t=bt-DCIdvQbnd1HggcUSvTQ