What is important to say is the user only writes
RCC_CR.
RCC_PLLCFGR.
RCC_CFGR.
as the command in the terminal..
Sure, that's one way to do it but I rarely type in anything at the terminal. I might type in "rcc." to get a instant upload of the registers as they are *right now* but I do almost everything in my editor.
Many people here think that one types on some old serial terminal and waits for Forth to reply via a slow UART like C users do with printf debugging.
The reality is that Forth often leads with new things that other systems don't have. Some very smart Forth people are always experimenting with new concepts and pushing the boundaries.
For instance my 'terminal' has no USART component because it works over SWD with full flow control, via USB. It's so fast that I can dump the (pretty printed, formatted) contents of registers as seen in my previous post to my screen in a few microseconds.
You can have the same thing with C if you buy an expensive Segger, but all I need is a STM32 Disco or Nucleo board for the SWD/USB dongle.
I type the Forth source code I want run (in the target MCU) in my editor and when I hit the 'make' button in the editor toolbar, the source is uploaded to the mcu faster than I can see on the SWD terminal screen. Because it's too fast to see we have had to add a terminal beep for warnings and an automatic upload abort for errors.
We want it even faster and are working on a SPI terminal atm plus a bunch of other exciting development aids, such as using an external 16MB SPI flash to store Forth development aids for use with smaller Cortex-M0 devices with only 64KB flash.
These aids might be the entire SVD2FORTH peripheral register pretty print Words, the entire Bitfield Words, ascii pictures of pinouts etc. If we wanted to leave the $2.50 SPI memory chip with the device, we could include schematics and diagnostic flowcharts for the tech servicing it a decade later.
We have already adapted to the new paradigm of MCU's with no internal flash such as the RP2040 where we now store multiple dictionaries in the external QSPI flash. Mecrisp-Pico Forth was released on 23 Feb 2021, only a month after the RP2040 Pico itself was released for sale. This included the time it took to actually buy Pico devices for development.
In this 'golden age of embedded' where MCU's have never been cheaper, faster, or more featureful, Forth is flourishing.