Adafruit-circuitpython-rfm9x

The reset sequence has been revised to remove the need for internal Pull-Up resistors.
No changes to user code necessary.
This is consistent with the TinyLoRa,RFM69 and Arfduino Radiohead library implementations.
To keep the RST line High during normal use, Instead of switching to an input with a Pull-Up enabled, it is kept as an output and set High.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-rfm9x`.

Read the [docs](http://circuitpython.readthedocs.io/projects/rfm9x/en/latest/) for info on how to use it.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-rfm9x`.

Read the [docs](http://circuitpython.readthedocs.io/projects/rfm9x/en/latest/) for info on how to use it.

Implemented compatibility with the RadioHead library "Reliable DataGram" mode.
Received packets are "ACKed" and Transmitted packets wait for ACK response.

BREAKING CHANGES
There are "breaking changes" for anyone that had been setting the RadioHead headers directly.
There are now attributes for setting the header parameters and the rx_filter parameter for the receive function has been removed.

for send() the kwarg tx_header has been replaced by 4 individual kwargs: destination, node, identifier, flags

It is not normally necessary use the destination, node, identifier or flags awards when calling send()
They should be set during initialization using the attributes node and destination as in the examples.
The identifier and flags attributes are set automatically when using send_with_ack()
For a non-acked send() they may be set manually either via the attributes or kwargs



send() now returns a boolean status - if True, the send was completed, if False, the send timed out. Previously a Runtime error was thrown on the time out.

Notes
It has been difficult to make this work reliably. Packets will still be missed occasionally but now they will be reported. There are attributes that can be "tweaked" to help

rfm9x.ack_delay -- set a delay before the ACK packet is sent - this is necessary when the receive unit an MCU communication to a Raspberry Pi . The MCU can send it's ACK packet before the Raspberry Pi has resumed "listening". The default setting is "None" but setting it to .1 seconds may be necessary. The Arduino RadioHead library does not allow for this "ack_delay" and it it may be difficult to get this to work, especially with a Raspberry Pi.

rfm9x.retries -- set the number of ack retries

All of the existing examples will still execute without change.

There are examples for using this mode in rfm9x_node1_ack.py and rfm9x_node2_ack.py

other new examples
rfm9x_header.py -- receive packets and display the header and packet contents
rfm9x_node1.py -- uses adresses without ACK
rfm9x_node2.py -- companion to rfm9x_node1.py
rfm9x_rpi_simpletest.py - no LED and set pins for RaspBerry Pi
rfm9x_node1_bonnet.py -- similar to rfm9x_node1.py but for use with RPi and bonnet -- uses buttons to send packets



To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-rfm9x`.

Read the [docs](http://circuitpython.readthedocs.io/projects/rfm9x/en/latest/) for info on how to use it.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-rfm9x`.

Read the [docs](http://circuitpython.readthedocs.io/projects/rfm9x/en/latest/) for info on how to use it.

We have upgraded Pylint checks to use the latest version of Pylint and implemented usage of Black Python formatting. This does not change the functionality of the code - it is designed to bring it up to current standards and make it more readable.

* Remove pinned Pylint version number from build.yml file
* Synced `.pylintrc` file to match Adafruit standard
* Ran upgraded Pylint and applied any changes or new disables necessary
* Ran Black formatter and allowed application of changes across entire repo

For more information on using Pylint and Black on your code, check out [this guide on working with Pylint and Black](https://learn.adafruit.com/improve-your-code-with-pylint)

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-rfm9x`.

Read the [docs](http://circuitpython.readthedocs.io/projects/rfm9x/en/latest/) for info on how to use it.