Perfection is achieved not when there is nothing more to add, but when there is nothing left to fail. Going by that metric, [Stian]’s three-chip 6502 homebrew computer is the epitome of perfection. It’s a real, working, homebrew retrocomputer using only three chips: a CPU, some RAM, and a microcontroller to bootstrap the computer and provide a video output,
The key to this minimalist build is having the entire boot process controlled by an ATMega16 microcontroller, This interfaces to the 6502 through a dual-port SRAM, a 1 kilobyte Cypress CY7C130. This dual-port RAM allows the CPU and microcontroller to access the same bit of memory, making it easy to bootstrap a computer from a bit of AVR code.
Output is provided with [Stian]’s ATMega video text generator putting a 37×17 characters on any television with an RCA jack. While input isn’t handled yet, [Stian] says it should be possible with his AVR PS/2 keyboard library.
While other 6502 homebrew computers such as [Quinn Dunki] Veronica can reach unparalleled heights of complexity, there is a lot to be said about the minimalism of [Stian]’s three-chip computer. With some clever coding and a modified parts list, it may well be possible to put a retrocomputer in the hands of everyone with a bare minimum of cost and parts.
The Hackaday tips line is always full of the coolest completed projects, but only rarely do we see people reaching out for help on their latest build. We’ll help when we can, but [Tim]’s relay-based CPU has us stumped.
[Tim] already has the design of his relay CPU completed with a 12-bit program counter, sequencer, ALU, and a transistor-based ROM. The problem he’s having deals with the mechanics and layout of his homebuilt CPU. Right now, all the relays (PC pin, we guess) are glued top-down to a piece of cardboard. This allows him to easily solder the wires up and change out the inevitable mistakes. This comes with a drawback, though: he’s dealing with a lot of ‘cable salad’ and it’s not exactly the prettiest project ever.
The ideal solution, [Tim] says, would be a PCB with through-hole plating, but this isn’t easy or cheap for the home fab lab. We’d suggest some sort of wire wrap setup, but proper wire wrap sockets and protoboards are for some reason unreasonably expensive.
If you have an idea on how to do the mechanical layout and connections of a relay-based computer, drop a note in the comments. [Tim] has a very cool project here, and it would be a shame if he were to give up on it due to a lack of tools.
Video below, and if you’re having a problem with a project, feel free to send it in.
Continue reading “How Do You Build a Relay CPU?”
Your desktop has two, four, or even eight cores, but when’s the last time you’ve seen a multicore homebrew computer? [Jack] did just that, constructing the DUO Mega, a 16 core computer out of a handful of ATMega microcontrollers.
From [Jack]’s description, there are 15 ‘worker’ cores, each with their own 16MHz crystal and connection to an 8-bit data bus. When the machine is turned on, the single ‘manager’ core – also an ATMega328 – polls all the workers and loads a program written in a custom bytecode onto each core. The cores themselves have access to a shared pool of RAM (32k), a bit of Flash, a VGA out port, and an Ethernet controller attached to the the master core.
Since [Jack]’s DUO Mega computer has multiple cores, it excels at multitasking. In the video below, you can see the computer moving between a calculator app, a weird Tetris-like game, and a notepad app. The 16 cores in the DUO Mega also makes difficult calculations a lot faster; he can generate Mandelbrot patterns faster than any 8-bit microcontroller can alone, and also generates prime numbers at a good click.
Continue reading “16 core computer made of ATMegas”
We’ve been following the work of [Andrew Holme] and his homebrew GPS receiver for a while now. A few years ago, [Andrew] built a four-channel GPS receiver from scratch, but apparently that wasn’t enough for him. He expanded his build last year to track up to eight satellites, and this month added a Raspberry Pi for a 12-channel, battery-powered homebrew GPS receiver that has an accuracy of about 3 feet.
The Raspi is attached to an FPGA board that handles the local oscillator, real-time events, and tracks satellites automatically. The Pi handles the difficult but not time-critical math through an SPI interface. Because the Pi is attached to the FPGA through an SPI interface, it can also load up the FPGA with even more custom code, potentially turning this 12-channel receiver into a 16- or 18-channel one.
An LCD display attached to the FPGA board shows the current latitude, longitude, and other miscellaneous data like the number of satellites received. With a large Li-ion battery, the entire system can be powered for about 5 hours; an impressively portable GPS system that rivals the best commercial options out there.
When you’re building one of the best homebrew computers ever created, you’ll also want a great case for it. This was [Simon]’s task when he went about building an enclosure for his Kiwi microcomputer.
We were introduced to the Kiwi last year as the end result of [Simon] designing the ultimate computer from the early to mid-1980s. Inside is a 68008 CPU, similar to the processor found in early Macs and Amigas, two SID chips taken from a Commodore 64, Ethernet, support for IDE hard drives and floppy disks, and a video display processor capable of delivering VGA resolution video at 32-bit color depth. Basically, if this computer existed in 1982, it would either be hideously expensive or extraordinarily popular. Probably both, now that I think about it.
The case for the Kiwi was carefully cut from ABS sheets, glued together with acetone, and painted with auto body paint by a friend. It’s a great piece of work, but the effort may be for naught; [Simon] is reworking the design of his Kiwi computer, and hopefully he’ll be spinning a few extra boards for everyone else that wants a piece of the Kiwi.
With the launch of the Wii U yesterday, we were wondering exactly how long it would take for this new console to be broken wide open allowing for the execution of homebrew code. Technically, it only took a day, as [wraggster] shows us, but the results aren’t what you would expect. Right now, he’s using methods meant for the classic Wii to open his system up; probably not the best way to open up the Wii U, but a start nonetheless.
This hack revolves around the Super Smash Bros. Brawl exploit that allows for the execution of unsigned code. It’s called Smash Stack and is one of the more popular ways of getting homebrew code running on the old, last-gen Wii.
Of course [wraggster]’s hack is dependent on the fact the classic Wii has been open for homebrew development for years now, and only works because of the Wii U’s ability to play classic Wii games. This probably isn’t the direction Wii U hackers want to go into, but it does provide a way for anyone to get into the Wii U system without using any new tricks.
We’d bet you didn’t know there was a Nyan Cat game for the original PlayStation. Well, there wasn’t one until very recently. This isn’t a title that has been licensed by Sony, and we bet you won’t spend hours playing such a thing. But the concept has let [Haunted] hone his development skills.
We’re not certain how he’s getting around the copy protection for PSX games, but we know there are a few different exploits out there. If you happen to have your own method playing homebrew games you can even download the bin/cue files to try this out for yourself.
After the break you can watch a demo clip of the game. It boots like normal until you hit a black screen with white text which displays a loading percentage. This is followed closely by the rainbow spewing feline pastry. The sound takes a minute to play but you can be sure it’s there. Currently there’s no scoring system but that’s in the works for a future revision.
Continue reading “Nyan Cat: the PlayStation game”