FPGA Computer Covers A to Z

[F4HDK] calls his new computer A2Z because he built everything from scratch (literally, from A to Z). Well, strictly speaking, he did start with an FPGA, but you have to have some foundation. The core CPU is a 16-bit RISC processor with a 24-bit address bus and a 128-word cache. The computer sports 2 megabytes of RAM, a boot ROM, a VGA port and keyboard, and some other useful I/O. The CPU development uses Verilog.

Software-wise, the computer has a simple operating system, a filesystem, and basic programs like a text editor and an image viewer. Development software includes an assembler and a compiler for a BASIC-like language that resides on the PC. You can also run an emulator to experiment with A2Z without hardware. You can see a “car game” running on A2Z in the video below. You can also see videos of some other applications.

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Semi-automatic Mouse Requires No Permit

When [Kerry]’s son asked him if there was a way to make a mouse click rapidly, he knew he could take the easy way and just do it in software. But what’s the fun in that? In a sense, it’s just as easy to do it with hardware—all you have to do is find a way to change the voltage in order to simulate mouse clicks.

[Kerry] decided to use the venerable 555 timer as an astable oscillator. He wired a momentary button in parallel with the left mouse button. A 50k mini pot used as the discharge resistor allows him to dial in the sensitivity. [Kerry] found that he maxed out around 5 clicks per second when clicking the regular button, and ~20 clicks per second with the momentary button as measured here. The mouse still works normally, and now [Kerry]’s son can totally pwn n00bs without getting a repetitive stress injury. M1 your way past the break to check out [Kerry]’s build video.

There are lots of other cool things you can do with an optical mouse, like visual odometry for cars and robots.

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The Tiny SCSI Emulator

For fans of vintage computers of the 80s and 90s, SCSI can be a real thorn in the side. The stock of functioning hard drives is dwindling, and mysterious termination issues are sure to have you cursing the SCSI voodoo before long. Over the years, this has led to various projects that aim to create new SCSI hardware to fill in where the original equipment is too broken to use, or too rare to find.

[David Kuder]’s tiny SCSI emulator is designed for just this purpose. [David] has combined a Teensy 3.5 with a NCR5380 SCSI interface chip to build his device. With a 120MHz clock and 192K of RAM, the Teensy provides plenty of horsepower to keep up with the SCSI signals, and its DMA features don’t hurt either.

Now, many earlier SCSI emulation or conversion projects have purely focused on storage – such as the SCSI2SD, which emulates a SCSI hard drive using a microSD card for storage. [David]’s pulled that off, maxing out the NCR5380’s throughput with plenty to spare on the SD card end of things. Future work looks to gain more speed through a SCSI controller upgrade.

But that’s not all SCSI’s good for. Back in the wild times that were the 80s, many computers, and particularly the early Macintosh line, were short on expansion options. This led to the development of SCSI Ethernet adapters, which [David] is also trying to emulate by adding a W5100 Ethernet shield to his project. So far the Cabletron EA412 driver [David] is using is causing the Macintosh SE test system to crash after initial setup, but debugging continues.

It’s always great to see projects that aim to keep vintage hardware alive — like this mass repair of six Commodore 64s.

Mark 8 2016 Style

In the mid-1970’s there were several U.S.-based hobby electronics magazines, including Popular Electronics and Radio Electronics. Most people know that in 1975, Popular Electronics ran articles about the Altair 8800 and launched the personal computer industry. But they weren’t the first. That honor goes to Radio Electronics, that ran articles about the Mark 8 — based on the Intel 8008 — in 1974. There are a few reasons, the Altair did better in the marketplace. The Mark 8 wasn’t actually a kit. You could buy the PC boards, but you had to get the rest of the parts yourself. You also had to buy the plans. There wasn’t enough information in the articles to duplicate the build and — according to people who tried, maybe not enough information even in the plans.

[Henk Verbeek] wanted his own Mark 8 so he set about building one. Of course, coming up with an 8008 and some of the other chips these days is quite a challenge (and not cheap). He developed his own PCBs (and has some extra if anyone is looking to duplicate his accomplishment). There’s also a video, you can watch below.

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Apple II Web Server Written In BASIC

The Apple II was the machine that many say launched Apple as a company. As with many popular computers of the 1980s, the Apple II maintains a steady following to this day who continue to develop new hardware and software to keep the platform alive.

[deater] had scored an Uthernet II Ethernet interface for his Apple IIe, based off the venerable W5100 chipset. He decided to have some fun and wrote a webserver for the Apple II in BASIC. The program sets up the Ethernet card with a series of PEEKs and POKEs, and then listens out for incoming packets before responding with the requisite data loaded from floppy disk.

The server can deal with HTML, text, and even JPEG and PNG images. It’s even compliant with RFC 2324. It does suffer from some limitations however — the disk format used can only hold 140 kB, it can only serve an 8kB file at a time, and due to using a lot of string manipulation in the code, is painstakingly slow.

Before you get too excited, the machine is running on a local network only, so you can’t check it out from here. However, [deater] has kindly released the source code if you wish to run it for yourself.

If you’re thirsty for more 8-bit action, check out this Apple II playing animated GIFs.

Google Scrubs Brillo, Reveals Android Things

Another week goes by and another new IoT platform surfaces. Google has announced Android Things, a build of the mobile operating system designed for smart devices rather than the latest slab of mobile eye-candy. The idea is that the same Android tools, framework and APIs that will already be familiar to app developers can be used seamlessly on IoT Things as well as in the user’s palm.

Of course, if this is sounding familiar, it’s because you may have heard something of it before. Last year they announced their Project Brillo IoT platform, and this appears to be the fruit of those efforts.

So you may well be asking: what’s in it for us? Is this just another commercial IoT platform with an eye-watering barrier to entry somewhere, or can we join the fun? It turns out the news here is good, because as the project’s web site reveals, there is support for a variety of Intel, NXP, and Raspberry Pi development boards. If you have a Raspberry Pi 3 on your bench somewhere then getting started is as simple as flashing a disk image.

The Things team have produced a set of demonstration software in a GitHub repository for developers to get their teeth into. Never one to miss an opportunity, the British Raspberry Pi hardware developer Pimoroni has released an Android Things HAT laden with sensors and displays for it to run on.

The IoT-platform market feels rather crowded at times, but it is inevitable that Android Things will gain significant traction because of its tight connections with the rest of the Android world, and its backing by Google. From this OS will no doubt come a rash of devices that will become ubiquitous, and because of its low barrier to entry there is every chance that one or two of them could come from one of you. Good luck!

Computers For The Masses, Not The Classes

Retro is new again, and everywhere you look you’ll find films, documentaries, and TV shows cashing in on the nostalgia of their target audience. There is one inaccuracy you’ll find with this these shows: Apple computers are everywhere. This isn’t a historical truth – Commodore was everywhere, the C64 was the computer the nerds actually used, and to this day, the Commodore 64 is still the best-selling computer in history.

Commodore is gone, replaced with a superfund site, but the people who made the best computers in history are still around. At the 2016 Hackaday SuperConference, Bil Herd gave a talk on the second act of Commodore’s three-act tragedy. Bil is a frequent contributor around these parts, and as always he illuminates the 1980s far better than Halt and Catch Fire ever could.

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