Ethernet VS DxCore

arduino.cc has a lot of tutorials!

I was gonna say the arduino.cc site but that works too.

When you write your code and compile it, what environment are you doing it in? Are you using an online cloud service like arduino.cc's IoT cloud? Or have you downloaded and installed the Arduino IDE application from arduino.cc's software download page?

There are tons of libraries for the Arduino platform that people have written and there are many available for use with this module, so you don't have to do any super heavy lifting programming-wise. In the Arduino IDE you can download from arduino.cc I installed a couple of libraries just now as a test. The reason I installed them is because almost every library comes with several short example programs showing how to use the various features that their library offers.

Did all of it make sense? Could you do the projects he shows by yourself without starting and stopping the video? That might show areas that you would want to brush up on. Another great idea is to go through all of the commands on the arduino.cc language reference page. Make sure you instinctively understand what each function listed does and experiment with any that you aren't familiar with.

There are also IoT cloud style dashboards at places like arduino.cc that let you add various widgets for dials and controls to represent the data you have locally with your Arduino.

Mentioned at arduino.cc. Designed to generate a periodic interrupt, I'll have to code a little state machine to change the interval at every firing.

Without a good explanation from them I really wouldn't put much stock in it. If anything they're probably just trying to steer people away from CH340 devices in part because they are problem children and because arduino.cc themselves don't use them.

Ontop of this, step 3 and 5 are a must in learning. And don't think "it's just blinking, lame" think more of "what can I do with this?" Use arduino.cc for reference.

Did you browse the examples here: https://github.com/SpenceKonde/DxCore/tree/master/megaavr/libraries/Wire/examples ?

This looks similar to what is available on the newer Dx family. The Arduino core documents this, so it may be worth reading through the source to see how it is achieved: https://github.com/SpenceKonde/DxCore/blob/master/megaavr/extras/Ref_Analog.md

As I mentioned upthread, there is a very good Arduino core for the Dx chips. Even if you don't use it, the documentation alone is worth reading through: (https://github.com/SpenceKonde/DxCore). The same author also maintains cores for various ATTiny families.

DxCore tells the Arduino IDE how to use the DA/DB series... https://github.com/SpenceKonde/DxCore

I'm a great fan of the newer AVR-DA and -DB chips as they offer much more value for money. They run at 24MHz without a crystal, have 16K SRAM and 128KB flash, more peripherals (e.g. two UARTs) and can be programmed with just a USB/serial adapter (no hardware programmer required). Available in the same 28-pin DIP package for about the same price. There's an excellent Arduino core available with full instructions: https://github.com/SpenceKonde/DxCore

The newer chips are really easy to use. All the chip really needs is the usual soft reset circuit (10K resistor + 100nF cap) and a 100nF cap on each power pin. Read through the readme's here: https://github.com/SpenceKonde/DxCore

Try the new AVR-Dx family. Still familiar AVR but will run at 24MHz down to 1.8V without a crystal. You can pick up e.g. AVR128DA28 in 28 pin DIL with 16K RAM and 128K flash for a couple of pounds/dollars/euros. Put it on some strip board with a couple of capacitors and resistors. The supporting Arduino core is https://github.com/SpenceKonde/DxCore