Perhaps the nomenclature needs to be more strictly defined, but I have to agree with the notion that " ... using antique chips students learn more about microcontrollers, latches, multiplexers and digital electronics."

Microcontrollers, by contrast with microprocessors, have the resources on-chip, so the "latches, multiplexers and digital electronics" are not so often required. I'd probably steer students in the direction of a microprocessor as the core of a microcontroller course, so that they gain an appreciation of how the internal logic and external logic have to work together. Starting with a monolithic microcontroller such as the self-contained JTAG-equipped chips from SiLabs, among others, which offer little ability to interface external hardware, is a bit limiting. Now, the reason there exists such a wide range of these devices is exactly because there are many things that they might be called upon to do, but they often are available in a variation that has precisely what's needed for a particular task, so no external hardware need be crafted. In most cass, it's possible to use a basic 805x variant of some sort and attach external hardware, but why would one want to do that.

In order to learn the ins and outs of dealing with hardware interfacing, however, it's pretty educational to start with, a Z-80 or 6802, add the clock generator, add the program store and read/write memory, and a bit of I/O, perhaps starting with registers and tristate buffers, and maybe a UART. That way one learns about system timing, interrupts, and other details that one can overlook far too easily with single-chip MCU's.

Some early Motorola MCU's actually were constructed in such a way that the internal bus was observable from the outside if one paid careful attention. Single-chippers started out simple and simply grew in degree of integration with their peripherals and in complexity. Motorola's series of single-chippers, starting with the 8-bit 6801, a contemporary of the 805x series and going up through the 32-bit MCU's in their 68xxx family illustrate that very well.

There's much to learn by fabricating one's own microcontroller system using decades-old hardware, not that anyone would do that in a commercial product, but just as an educational exercise. That's valuable so long as one is after the education and not the work-product.

RE