Reset Nano Every via 1200 Baud touch

Hardware Nano Family Nano Every
9

OK, well it looks like you have things fairly well worked out, but I'll provide the instructions anyway for the benefit of others who are interested in the subject:

Install MuxTO boards platform

Since Arduino has not provided Boards Manager installation support, it is necessary to do a manual installation of the boards platform for the "MuxTO" chip:

  1. Select File > Preferences from the Arduino IDE menus.
  2. Take note of the path shown in the "Sketchbook location" field.
  3. Click the Cancel button.
  4. Run the following Git command:
    git clone --depth 1 https://github.com/arduino/ArduinoCore-samd -b muxto <Sketchbook location>/hardware/arduino-dev/samd/
    (where <Sketchbook location> is the path you learned from the Arduino IDE preferences in step 2)

Install toolchain

The manual installation of the "MuxTO" boards platform only provided the configuration files and core library. We also need the correct version of the compilation and upload toolchain. The easiest way to get that is by installing the equivalent boards platform via the Arduino Boards Manager:

  1. Select File > Preferences from the Arduino IDE menus.
  2. Add the following URL to the "Additional Boards Manager URLs field:
    https://www.mattairtech.com/software/arduino/package_MattairTech_index.json
    If you have other URLs in the field already, use a comma (,) separator.
  3. Click the OK button.
  4. Select Tools > Board > Boards Manager from the Arduino IDE menus.
  5. Wait for the updates to finish.
  6. Scroll down through the available boards platforms until you find "MattairTech SAM D|L|C core for Arduino by MattairTech LLC". Click on it.
  7. From the dropdown version menu, select "1.6.17".
  8. Click the Install button.
    (if you already have a different version of the platform installed, click the
  9. Wait for the installation to finish.
  10. Click the Close button.

Configure Arduino IDE

A comment in the MuxTO firmware sketch specifies the appropriate custom board options:

Compile with
fqbn=arduino:samd:muxto:float=default,config=enabled,clock=internal_usb,timer=timer_732Hz,bootloader=4kb,serial=two_uart,usb=cdc
to obtain the binary for Serial-to-USB converter + UPDI programmer on the Arduino Nano Every (MuxTO for brevity)
  1. Select Tools > Board > MattairTech SAM D|L|C core for Arduino by MattairTech LLC (in sketchbook) > Arduino MuxTO from the Arduino IDE menus.
  2. Select Tools > Floating Point > Print & String use auto-promoted doubles only from the Arduino IDE menus.
  3. Select Tools > Build Options > config.h enabled (mostly code size reductions) from the Arduino IDE menus.
  4. Select Tools > Clock Source > INTERNAL_USB_CALIBRATED_OSCILLATOR from the Arduino IDE menus.
  5. Select Tools > Timer PWM Frequency > 732.4Hz (16-bit) from the Arduino IDE menus.
  6. Select Tools > Bootloader Size > 4KB_BOOTLOADER from the Arduino IDE menus.
  7. Select Tools > Serial Config > TWO_UART_NO_WIRE_NO_SPI from the Arduino IDE menus.
  8. Select Tools > USB Config > CDC_ONLY from the Arduino IDE menus.

Open MuxTO firmware sketch

  1. Clone or download the arduino/ArduinoCore-megaavr repository to a convenient location on your computer.
  2. Select File > Open from the Arduino IDE menus.
  3. From your copy of the arduino/ArduinoCore-megaavr repository, select firmwares/MuxTO/MuxTO.ino
  4. Click the Open button.
    The "MuxTO" sketch will now open in the Arduino IDE. Note that this is a multi-file sketch. Each file is shown in the Arduino IDE as a tab.

You are now ready to compile and upload the MuxTO firmware sketch.