Now you can have a Zilog computer in the form factor of a matchbox. The RamBlade is a tiny PCB that uses a Parallax Propeller IC to implement the CP/M language. The OS is stored on a microSD card, with a four-pin serial interface (3V3, GND, SO, SI) that allows operation via a terminal program.
Smaller and more resilient than building your own from ancient logic chips, we see this a way to get a whole new set of people interested in this old technology.
[Thanks Oldbitcollector]
[Donn] wanted know exactly what is going on inside of a processor so naturally he built a CPU out of TTL components. He had previously built a couple of versions of a computer based on the Z80 processor. Using the troubleshooting skills he learned and a second-hand textbook, he set to work using 74LS series chips connected using the wire-wrap method we’re familiar with from other cpu projects.
The finished product runs well at 1.8 megahertz, but he also included a 2 hertz clock and a step clock for debugging. At the slower speeds, the register board (seen at the left in the picture above) lights LEDs and can be used to tell what the CPU is currently working on. Programming is accomplished through either a dumb terminal or a PC running a terminal emulator.
His writeup is from about five years ago but that didn’t prevent us from getting that fuzzy feeling in the geek-center of our brain when we read about it. It is well written and thorough so if you’re into this kind of thing there’s plenty to enjoy.
[Thanks Raleigh]
We’ve seen Z80 processor based computers before but they usually use a printed circuit board to easily and reliably connect all the components. [Marton] sent us his Z80 based computer from a while back that is built entirely on prototyping board. He made his own video board that utilizes a TV as the monitor and his own mainboard incorporating a keyboard controller. The system runs at 4 MHz, has 32k of ram, and runs [Marton’s] own system software which he has posted. Its quite impressive and we love the protoboard porn with thousands of grey wires running everywhere.
[Marton] used the resources on [Hans Summers’] site for his project. Make sure to check it out if you’re interested in a broader background concerning DIY Zilog Z80 computers.
The N8VEM is a homebrew computer project based on the classic Z80 microprocessor. It’s designed to be easy to build using large TTL DIP components instead of SMD devices. It runs the CP/M operating system and all drives are virtual in RAM/ROM. While the base hardware is interesting, we really like the potential for expansion using a backplane. Have a look at the project’s Hardware Overview to see extra boards like the bus monitor and the prototyping board. We found out about this project on [Oldbitcollector]’s blog; he’s using a Parallax Professional Development Board to create a VT100 terminal for the N8VEM.
