To the people who answered my original question, THANK YOU. Responses were helpful. I didn't know whether a thank you would be welcomed or would be viewed as a distracting piece of social fluff.
I went straight to Muhammed's answer and found much the kind of thing that I was looking for. I also noticed BerndAnton's response and saw the things he mentioned, in passing, as I was checking out Muhammed's leads.
I would have chosen either of these over the "selected as best" response, because the selected response does not lead to the software (firmware) that comes loaded into the board when you first receive it. That was what I was hoping to find. Instead, that destination seems to have fine points, tweaks, and updates - all of which may be excellent for customers who are already at home with ST's offerings, but is unfortunate for a novice. For a novice, that answer should have referenced the page, then indicated that you needed to install the Cube IDE and then rummage through the source tree, and perhaps mentioned a starting point, or a principle for finding an appropriate starting point.
I'm a software person who writes C, C++, C#, Java, Pascal, Ada, Asm, Forth, etc, on big iron. I am learning CM4 assembly language, wondering about using HAL, and hoping to collaborate with hardware people, as I do in my day job. The HAL manual is 2600 pages long. It needs a table of contents in the front, by the way, because a novice doesn't know where to start.
STM boards are fantastically capable; there is an abundance of information; but a trail of breadcrumbs is still needed. I am taking some Udemy courses: GNU Asm for ARM, FreeRTOS, and Demystifying DMA, for example. Without some of those courses, I wouldn't have been able to get started with the STM32 boards.
From the perspective of an outsider, it was helpful to know that when I had installed the STM Cube IDE (which I really like, BTW), that it already had most of the stuff I wanted to look at, hidden within its source tree. Even more opaque than the www.stm.com site's organization, is the ST GitHub site, which has some really useful looking stuff, and some not so useful looking stuff, and a lot of repetition of the same artifact tweaked for each member of the product line, all in random order, with no index to help one to navigate.
I'm interested in the STM CRC32 unit, which I hope to use in conjunction with HAL from an assembler program. It will take me a week or two to get there, but I will, with your help and the help of Dr Google. Eventually, I'd like to use it through DMA, but that is a way in the future.
I'm really pleased with the ST products. I just want to learn more about how to use them and how to talk to them. Thanks for your attention.
