feat: move odfu example from note-outboard-dfu and update readmes

[rdlauer]

Migrating ODFU example from note-outboard-dfu repo

[Bucknalla]

Let's use the Fluent API which covers all four requests used here (hub.set, card.dfu, card.aux, dfu.status), and it's the target pattern for note-python users (see examples/binary-mode/upload/binary_upload_example.py) instead of hand-building {"req": ...} dicts + card.Transaction().

Suggested rewrite of configure_outboard_dfu (and the related import/var changes) in circuit-python/code.py:

import time
import board
import digitalio
import notecard
from notecard import card, dfu, hub

# The unique Product Identifier for your device. Claim one in a Notehub project.
productUID = "com.your-company.your-project"

# The firmware version reported to Notehub via dfu.status. Bump this (and change
# BLINK_DELAY) when you build a new image to update to.
FIRMWARE_VERSION = "1.0.0"

# Seconds the LED stays on/off. Change this to make the update visually obvious.
BLINK_DELAY = 0.5


def configure_outboard_dfu(nCard):
    """Put the Notecard online and enable Outboard Firmware Update for the host.

    Outboard Firmware Update requires the Notecard to be in "continuous" or
    "periodic" mode. On a Notecarrier F the DFU signals are routed over the
    Notecard's shared AUX pins, so card.dfu uses mode "aux" and card.aux is set
    to "off" to free those pins for DFU.
    """
    hub.set(nCard, product=productUID, mode="continuous", sn="circuitpython-notecard")

    # Enable Outboard Firmware Update and tell the Notecard the host MCU type.
    card.dfu(nCard, name="stm32", on=True, mode="aux")

    # Free the AUX pins so they can be used for Outboard Firmware Update.
    card.aux(nCard, mode="off")

    # Enable host DFU and report the running firmware version to Notehub.
    dfu.status(nCard, on=True, version=FIRMWARE_VERSION)


def main():
    """Enable Outboard DFU, then blink the built-in LED as the update payload."""
    i2c = board.I2C()
    nCard = notecard.OpenI2C(i2c, 0, 0, debug=True)

    configure_outboard_dfu(nCard)

    led = digitalio.DigitalInOut(board.LED)
    led.direction = digitalio.Direction.OUTPUT

    print("Running firmware version {}. Hit CTRL-C to stop.".format(FIRMWARE_VERSION))
    while True:
        led.value = True
        time.sleep(BLINK_DELAY)
        led.value = False
        time.sleep(BLINK_DELAY)


main()

Note the parameter/variable rename from card to nCard (matching the README's fluent API example) — it was renamed to avoid colliding with the notecard.card module import.

[Bucknalla]

See comment re-changing to Fluent API

[rdlauer]

@Bucknalla I missed your complete code sample but Claude added the fluent API usage for me. Also while in here I updated the github actions to the latest versions to avoid the Node 20 deprecation warnings. Ready for a review.