N8VEM Single Board Z80 Computer

January 10, 2009 by 17 Comments

n8vem

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.

This Snappy 8-Bit Microcomputer Brings The Speed To Retrocomputing

October 21, 2022 by 45 Comments

When the need for speed overcomes you, thoughts generally don’t turn to 8-bit computers. Sure, an 8-bit machine is fun for retro gameplay and reliving the glory days, and there certainly were some old machines that were notably faster than the others. But raw computing power isn’t really the point of retrocomputing.

Or is it? [Bernardo Kastrup] over at The Byte Attic has introduced an interesting machine called the Agon Light, an 8-bit SBC that’s also a bit like a microcontroller. The machine has a single PCB that looks about half as big as an Arduino Uno, and sports some of the same connectors and terminals around its periphery. The heart of the Agon Light is an eZ80 8-bit, 18.432 MHz 3-stage pipelined CPU, which is binary compatible with the Z80. It also has an audio-video coprocessor, in the form of an ESP32-Pico-D4, which supports a 640×480 64-color display and two mono audio channels. There’s no word we could find of whether the ESP32’s RF systems are accessible; it would be nice, but perhaps unnecessary since there are both USB ports and a PS/2 keyboard jack. There’s also a pin header for 20 GPIOs as well as I2C, SPI, and UART for serial communication.

The lengthy video below goes into all the details on the Agon Light, including the results of benchmark testing, all of which soundly thrash the usual 8-bit suspects. The project is open source and all the design files are available, or you can get a PCB populated with all the SMD components and just put the through-hole parts on. [Bernardo] is also encouraging people to build and sell their own Agon Lights, which seems pretty cool too. It honestly looks like a lot of fun, and we’re looking forward to seeing what people do with this.

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VCF East 2021: Novasaur TTL Computer Sets The Bar

October 25, 2021 by 12 Comments

There was certainly no shortage of unique computers on display at the 2021 Vintage Computer Festival East; that’s sort of the point. But even with the InfoAge Science and History Museum packed to the rafters with weird and wonderful computing devices stretching back to the very beginning of the digital age, Alastair Hewitt’s Novasaur was still something of an oddity.

In fact, unless you knew what it was ahead of time, you might not even recognize it as a computer. Certainly not a contemporary one, anyway. There’s nothing inside its Polycase ZN-40 enclosure that looks like a modern CPU, a bank of RAM, or a storage device. Those experienced with vintage machines would likely recognize the tight rows of Advanced Schottky TTL chips as the makings of some sort of computer that predates the 8-bit microprocessor, but its single 200 mm x 125 mm (8 in x 5 in) board seems far too small when compared to the 1970s machines that would have utilized such technology. So what is it?

Inspired by projects such as the Gigatron, Alastair describes the Novasaur as a “full-featured personal computer” built using pre-1980 components. In his design, 22 individual ICs stand in for the computer’s CPU, and another 12 are responsible for a graphics subsystem that can push text and bitmapped images out over VGA at up to 416 x 240. It has 512 K RAM,  256 K ROM, and is able to emulate the Intel 8080 fast enough to run CP/M and even play some early 80s PC games.

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An 8085 Retrocomputer From The Heart

March 7, 2020 by 21 Comments

The world of 8-bit retrocomputing splits easily into tribes classified by their choice of processor. There are 6809 enthusiasts, 6502 diehards, and Z80 lovers, each sharing a bond to their particular platform that often threads back through time to whatever was the first microcomputer they worked with. Here it’s the Z80 as found in the Sinclair ZX81, but for you it might be the 6502 from an Apple ][. For [Craig Andrews] it’s the 8085, and after many years away from the processor he’s finally been able to return to it and recreate his first ever design using it. The SBC-85 is not wire-wrapped as the original was, instead he’s well on the way to creating an entire ecosystem based around an edge-connector backplane.

The CPU board is an entire computer in its own right as can be seen in the video below the break, and pairs the 8085 with 8k of RAM, a couple of 2732 4k EPROMs, and an 8155 interface chip. This last component is especially versatile, providing an address latch, timer, I/O ports, and even an extra 256 bytes of RAM. Finally there is some glue logic and a MAX232 level shifter for a serial port, with no UART needed since the 8085 has one built-in. The minimal computer capable with this board can thus be slimmed down significantly, something that competing processors of the mid 1970s often struggled with.

Craig’s web site is shaping up to be a fascinating resource for 8085 enthusiasts, and so far the system sports that backplane and a bus monitor card. We don’t see much of the 8085 here at Hackaday, perhaps because it wasn’t the driver for any of the popular 8-bit home computers. But it’s an architecture that many readers will find familiar due to its 8080 heritage, and could certainly be found in many control applications before the widespread adoption of dedicated microcontrollers. It would be interesting to see where Craig takes this next, with more cards, and perhaps making a rival to the RC2014 over in Z80 country.

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Five Years Of The Raspberry Pi Model B+ Form Factor, What Has It Taught Us?

July 8, 2019 by 84 Comments

With all the hoopla surrounding the recent launch of the new Raspberry Pi 4, it’s easy to overlook another event in the Pi calendar. July will see the fifth anniversary of the launch of the Raspberry Pi Model B+ that ushered in a revised form factor. It’s familiar to us now, but at the time it was a huge change to a 40-pin expansion connector, four mounting holes, no composite video socket, and more carefully arranged interface connectors.

As the Pi 4 with its dual mini-HDMI connectors and reversed Ethernet and USB positions marks the first significant deviation from the standard set by the B+ and its successors, it’s worth taking a look at the success of the form factor and its wider impact. Is it still something that the Raspberry Pi designers can take in a new direction, or like so many standards before it has it passed from its originator to the collective ownership of the community of manufacturers that support it?

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Hackaday Links: July 31, 2016

July 31, 2016 by 14 Comments

Going to DEF CON this week? Getting into Vegas early? We’re having a meetup on Wednesday, in the middle of the day, in the desert. It’s all going down at the grave of James T. Kirk. Rumor has it, the Metrons will abduct a few of us and make us fight to the death on a planet with impossible geology.

The Hara Arena is closing down. The Hara Arena in Dayton, Ohio is the home of Hamvention, the largest gathering of amateur radio enthusiasts in the US. I was there last May, and I can assure you, the Hara Arena has fallen into a state of disrepair. The ARRL reports hamvention will be at a new venue next year. The last scheduled event, after which there will be an auction for venue equipment and furniture, will be on August 27th. It’ll be a comic book and toy show.

Hackaday.io has a log of projects. Some might say it has too many projects. The search is great, but sometimes you just want to look at a random project. That’s the problem [Greg] solved with his Hackaday.io randomizer. It returns a random Hackaday.io project, allowing you to gawk at all the boards and resistors found within.

Primitive Technology is a YouTube channel you should watch. It’s a guy (who doesn’t talk), building everything starting with pre-stone age technology. He built a house with a heated floor, somewhat decent pottery, and this week he entered the iron age. The latest video shows him building a squirrel cage fan out of clay and bark to smelt iron. The ore was actually iron-bearing bacteria, mixed with charcoal and wood ash, and placed into a crude but accurate smelting furnace. The end result is a few bb-sized grains of iron and a lot of melted flux. That’s not much, and is certainly not an accurate portrayal of what was being done 5,000 years ago, but it does mean the Internet’s favorite guy in the woods has entered the iron age while completely skipping over bronze.

Freeside Atlanta says they’re the largest hackerspace on the east coast, and to show off all the cool goings on, they made a walk through video.

Hackaday has a retro edition. It’s a wide selection of Hackaday posts presented in a format without JavaScript, CSS, ads, or any other Web 2.0 cruft. There’s an open challenge for anyone to load the retro site with a 4004 CPU. I know it can be done, but no one has presented evidence of doing it. [Lukas] just sent in his retro submission with a Z80 single board computer displaying some of the page on seven-segment displays. It’s basically a terminal emulator connected to a laptop that does most of the work, but this is the most minimal retro submission we’ve ever received.

Homebrew 68k Extravaganza

September 4, 2012 by 45 Comments

Introduced in 1979, the Motorola 68000 CPU was first used in very expensive and very high-end workstations from the likes of Sun and SGI. As the processor matured it became well-known for its use in the original Macintosh, early Amigas, and even the TI-89 graphing calculator and a few video game consoles such as the Sega Genesis and Atari Jaguar.

A few days ago when I posted a homebrew computer build based on the 65816 CPU, I lamented the lack of builds using the venerable Motorola 68k. Hackaday readers were quick to point out the many homebrew computers making use of this classic CPU, and I’m glad to post them here.

First up is an amazing 68008 build featuring an IDE disk interface, a floppy disk interface, 10base-T Ethernet connectivity, a real-time clock, and two SID synthesizer chips. As far as features go, this build takes the cake. Pity I can’t find a writeup.

Here’s a 68000-based computer built around the S-100 bus. Like the first computer to use the S-100 bus, the Altair 8800, this computer is plugged into a backplane that breaks out the data, address, and interrupt lines to every device on the bus.

Of course, no mention of backplane computers would be complete without a Eurocard version. [N8VEM] built a 68000 computer able to be plugged in to a backplane along with an IDE controller card and a display controller.

Finally, in true ‘giant mess of wires’ spirit, [Dajgoro] sent in his 68k single board computer featuring 512 kB of RAM and a 16k ROM. [Dajgoro] also took the time to wire in a PIC microcontroller, allowing him to expand his computer far beyond what vintage components would allow.

The 68k was – and still is – a very powerful CPU that far surpasses the capabilities of the 6502 and Z80 homebrew computers we see from time to time. Short of building a 486 or Pentium-based computer from scratch, building a 68k machine is one of the crowning achievements of hardware hackery, and something we hope to see more of in the future.