Z80 Assembly 64: Implementing a Simple Network Protocol (Link Layer)

The OSI Model and the Link Layer Networking is organized into layers. The Link Layer (Layer 2 of the OSI model) is the lowest level of communication, responsible for sending and receiving frames (raw data packets) between two connected devices (e.g., two computers on a local network). Goal: To wrap user data with a small header and footer so the receiver knows where the packet begins, where it ends, and whether it’s valid. ...

September 27, 2025

Z80 Assembly 63: Interfacing with the Z80 SIO (Serial I/O)

The Role of the Z80 SIO The Z80 SIO (Serial Input/Output) chip is a sophisticated peripheral that acts as a dual-channel UART (Universal Asynchronous Receiver/Transmitter). It handles all the complex timing, start/stop bit generation, and error checking for serial communication entirely in hardware. Advantage: The SIO makes robust serial communication (like RS-232, modem, or network) fast and reliable, saving the Z80 CPU thousands of cycles compared to software bit-banging (Part 40). ...

September 27, 2025