For years, it's generally accepted that 8 bit microcomputer CPUs does not have hardware support for protected mode. However, my recent discovery shows otherwise. In this video, I will show you how to implement memory and I/O protection on a z80 with minimal external circuit.

Links:
General Introduction to the Z80:    • Looking at the Zilog Z80 - NEW SERIES!  
The history of Zilog and Z80:    • Intel’s worst Nightmare  
Z80 assemnly tutorial:    • Z80 Assembly Language for the ZX Spec...  
CPU timeline: https://www.vgamuseum.info/index.php/cpu
Support this project on Patreon:   / andy18650  
Join our discord server:   / discord  
GitHub repo for the project: https://github.com/Andy18650/HEC-Mode...

Chapters:
0:00 The Z80 has a protected mode
0:32 Literally the worst intro video ever
0:52 What is Z80
1:52 Why is protected mode important?
3:10 Undocumented? Really?
4:10 How to implement protected mode
10:34 Final Conclusion
12:10 Clickbait?
12:54 Applications of the protected mode
14:27 An interesting story

Edit: this video is the third release! I managed to iron out all problems in the second one, which includes:
1, CRT noise everywhere
2, intro video footages are not muted (you can hear computer noise over the music)
3, 0:55 the (absolutely terrible) B-roll is not muted (You can hear me watching a video about the Mindset computer in the background... I thought it was fine since I could just mute that, obviously I did not...)
4, 1:56 my voice is strangely 'doubled' making me sound like the Borg Queen (this does not happen at all when I'm editing the video! In my editing software the two voices just overlap entirely and become louder)
5, 2:13 that B-roll (and the horrible CRT noise) is not muted
6, 2:45 a weird 'ding' caused by speeding up the video to hide a long blank
7, music is still too loud, but my editing machine probably have a voice enhance feature enabled somewhere too. This problem is much less pronounced on it (and maybe some other computers but probably not all).