So again I apologize as I meant no offense.
Apology accepted, but it was not necessary. Everyone is entitled to their own opinion. And I can also appreciate the desire to make "something from scratch" instead of having to wade into unknown waters trying to program who-knows-what kind of microprocessor.
Many years ago, near the end of the TTL (Transistor-Transistor Logic) era, and at the beginning of the CMOS logic era, I became interested in generating NTSC composite sync for use in a video game I was attempting to design. So, having some time on my hands and a large stock of TTL parts, I designed and bread-boarded a complete NTSC fully interlaced composite sync generator. I was soooo happy when I finally got it to work and had the interlace timing correct. Then, a few weeks later IIRC, I ran across an integrated circuit that did exactly the same thing for a really cheap price. I was crushed! All that work (weeks of it) just to re-invent someone else's wheel! I was determined to never let that happen to me again. And so led the path down the road to microprocessors... And I never did get around to finishing that video game because others beat me to it.
I like programming at the machine level, or register-level programming as some call it, "banging on the bits" with ones and zeroes of machine code. However, this gets tedious after hand-keying in a few dozen machine instructions. Hence the need at the beginning for a boot loader program you key in once and then use to load other programs, typically from a punched paper tape reader back then. From the ones and zeroes of machine language you advance to symbolic assembly language. More structure there, but still not very abstract yet. What is needed is a "microphone mouse" you can pick up, like Scotty did in the Star Trek movie "The Voyage Home," and say to it, "Computer! Design me a Morse Code flasher! Keep It Simple Stupid Computer."
So all those languages and operating systems you mentioned are just "fluff" the computer weenies have piled on top of machine language, to try to get us to the "microphone mouse" stage of "computer programming." IMO we're not there yet, no matter how sincerely Siri tries to help us.
I almost missed the
second microprocessor revolution where ordinary Joes and Janes, armed with a laptop and an inexpensive USB interface pod, could create and download programs into embedded microprocessors dedicated to performing just
one task, usually a task waaaay below the potential capability of the μP. Said use was eminently practical 'cause the μP devices had become
dirt cheap. Some were less expensive than a quality socket to mount them to a circuit board. Compare that to the thousand-dollar-plus development system I needed to develop Intel 8085 applications from the late 1970s through the early 1990s.
By 2000 I had given up on embedded microprocessors, although I did try to keep abreast of new developments, in particular the extremely low-power Texas Instruments MSP430 series, available with insanely high-precision analog-to-digital converters. I still thought the entry level price was too high for hobby use, but somewhere between then and now that all changed.
@KrisBlueNZ, before he unexpectedly died, clued me in on Microchip PICs and how easy and inexpensive it was to work with them. Later, I worked with
@chopnhack to help him design an interface between a PIC and an Allegro current sensor.
Haven't done anything lately since we moved to Florida last December, but definitely plan to pick it up again. I might even design and program an LED Morse Code flasher... with optional sound beeps to make it easier to locate by ear. Or maybe program it to send CQ CQ CQ de AC8NS CQ CQ CQ K. On demand, of course, for use while walking around the flea market at a hamfest. Or maybe use it to control an electronic keyer on my ham radio transceiver, so I can automagically send out requests for contacts, giving my wrist a break at the telegraph key. All of this already exists of course in one form or another. I would be re-inventing someone else's wheel, but at least it would be a
custom wheel of my own design.
So try out the ideas of
@Alec_t and the
@AnalogKid, and if you get something that does what you want it to do, there is probably an itsy bitsy teeny weenie surface-mount version available too. The important thing is to have FUN with whatever technology you choose.