GPIO over SPI over GPIO - IO from Scratch - Part 5
26:14
Hardware SPI - IO from Scratch - Part 6
20:11
Adding GPIO - IO from Scratch - Part 1
22:52
The Madness of Z80 I/O
30:04
SPI (Bit Banging)- IO from Scratch - Part 4
44:14
Building C Programs for a 6502 breadboard computer and customizing cc65
15:19
Add USB To Your Electronics Projects! - The USB Protocol Explained
31:13
Hardware SPI Continued - IO from Scratch - Part 7
33:00