reZet80 PIONEER README [last modified: 2023-01-20]
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Welcome to reZet80!
reZet80 stands for "Reset me back to the 80s with the Z80".
reZet80 features a set of retro projects to develop computing and
arcade systems that resemble the Z80 machines of the late 70s and early 80s.
All systems are built from scratch and not copies of any other Z80 system.
The development process includes hardware design and low-level software
programming in Assembler. I will develop and build every single pcb trace
and every single bit of machine code by myself.
DIYIB: Doing it yourself is believing!
And WYDYIWYG: What you do yourself is what you get!
I started reZet80 back in 2016.

The reZet80 PIONEER is an expandable modular stand-alone computer system
that could have been built in the late 70s.
In its basic configuration the reZet80 PIONEER is equipped with a Z80 CPU
card and a memory card with 1 KiB of static RAM and 2 KiB of ROM containing
a simple debug monitor. The maximum amount of RAM and ROM of the memory card
are 2 KiB and 4 KiB, respectively. The ROM can be upgraded to 14 KiB.
RAM can be extended to 12 KiB and further increased by the addition of
dynamic RAM.
Input and output are implemented by a 20-key keypad and a 16-digit display.
The mainboard also includes power supply sockets, on/off switch, reset
switch and memory and I/O decoding circuitry (8 I/O ports).

The following parts that were available in the mid to late 70s are used in
this project:
- Zilog Z80 (CPU, NMOS, 1976)
- Intel 2114 or compatible (1K x 4 bit static RAM, NMOS, 1976)
- Intel 2125 or compatible (1K x 1 bit static RAM, NMOS, 1976, alternative to 2114)
- Intel 2716 or compatible (2 KiB UV erasable EPROM, NMOS, 1977)
- Intel 8279 (Programmable Keyboard / Display Interface, NMOS, 1976)
- 74LS04 (inverter, LSTTL, 1975)
- 74LS138 (memory and I/O decoding, LSTTL, 1975)
- 74LS139 (memory and I/O decoding, LSTTL, 1975)
- 74LS154 (display and key decoding, LSTTL, 1976)
- 74LS244 (display buffer, LSTTL, 1976)
- 74LS245 (input and output port, LSTTL, 1976)
- 7-segment display (LED, 1970s)

reZet80 PIONEER directory hierarchy:
|- README                : this file
|- LICENSE               : reZet80 license
|- about_myself          : as it says
|- PIONEER_R0            : Release 0 (first release)
|- PIONEER_R1            : Release 1 (this second release)
|-- doc                  : technical specifications
|-- pix                  : pictures
|-- rom                  : ROM images
|-- sch                  : schematics
|-- src                  : source code
|-- pioneer              : build script
|-- README_Haunted_House : a few words about the first reZet80 game
|-- README_ROM_images    : 2 images in 2 flavours each
|-- CHANGELOG_PIONEER_R1 : changes since R0