The reZet80 PIONEER is an expandable modular stand-alone computer system that could have been built in the late 70s.
It is built from scratch and not a copy of any other Z80 system.
This project involves hardware and software development. I plan to develop and build every single pcb trace and every single bit of machine code by myself from scratch.
DIYIB: Doing it yourself is believing.
And WYDYIWYG: What you do yourself is what you get.
In its basic configuration the reZet80 PIONEER is equipped with 1 KiB of static RAM and 2 KiB of ROM containing a very simple debug monitor.
The maximum amount of onboard RAM and ROM 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 6-digit display (either 7-segment LEDs or TIL311 LEDs that are more costly).
The mainboard also includes power supply sockets, on/off switch, reset switch and memory and I/O decoding circuitry (8 I/O ports).
An expansion bus, a video card, a memory cartridge, a sound card based on the AY-3-8910 chip and a joystick are planned to be added later.
Plans for the future also include to enhance the debug monitor and to provide a text adventure, at least one arcade clone, an assembler, a disassembler, a debugger and a C compiler.
At the same time static memory chips like the 2125 (1K x 1 bit) and the 2114 (1K x 4 bit) were already available but were very expensive so memory was a scarce resource.
Dynamic RAM chips were more affordable back then. DRAM chips with a single +5V power supply like Intel's 2118 were available in 1979.
UV erasable 2 KiB PROMs with a single +5V power supply like Intel's 2716 were also available by 1977.
TI's TIL311 dates from 1972.
General Instrument's AY-3-8910 Programmable Sound Generator (PSG) was released in 1978.
