A 150MHz 6502 Co-Processor

If you are familiar with ARM processors, you may know of their early history at the 1980s British home computer manufacturer Acorn. The first physical ARM system was a plug-in co-processor development board for Acorn’s BBC Micro, the machine that could be found in nearly every UK school of the day.

For an 8-bit home computer the BBC Micro had an unusually high specification. It came with parallel, serial and analog ports, built-in networking using Acorn’s proprietary Econet system, and the co-processor interface used by that ARM board, the Tube. There were several commercial co-processors for the Tube, including ones with a 6502,  a Z80 allowing CP/M to be run, and an 80186.

As with most of the 8-bit generation of home computers the BBC Micro continues to maintain a strong enthusiast following who have not stopped extending its capabilities in all directions. The Tube has been interfaced to the Raspberry Pi, for instance, on which an emulation of original co-processor hardware can be run.

bbc-tube-screenshotAnd thus we come to the subject of this article, [Hoglet] and [BigEd]’s 150MHz 6502 coprocessor for the BBC Micro. Which of course isn’t a 6502 at all, but a 6502 emulated in assembler on an ARM which is in a way the very distant descendant of the machine it’s hosted upon. There is something gloriously circular about the whole project, particularly as the Pi, like Acorn, the BBC Micro, and modern-day ARM, has its roots in Cambridge. How useful it is depends on your need to run 8-bit 1980s software in a tearing hurry, but they do report it runs Elite, which if you were there at the time we’re sure you will agree is the most important application to get running on a BBC Micro.

We’ve featured the Tube interface before when we talked about an FPGA co-processor with a PDP/11 mode that was definitely never sold by Acorn. And we’ve also featured an effort to reverse engineer the primordial ARM from that first BBC Micro-based co-processor board.

BBC Micro image: Stuart Brady, Public Domain, via Wikimedia Commons.

Feel Extreme Workbench Envy After Seeing The Tempel

For those of us with space to spare, our workbenches tend to sprawl. The others who are more space limited will certainly feel envy at [Love Hultén]’s beautiful Tempel workbench.

The workbench appears at first to be a modern interpretation of a secretary’s desk. There are some subtle hints that it is no ordinary piece of furniture. The glowing model of our solar system on the front, for example.

With the front folded down, rather than the expected leather writing pad and letter sized drawers, a few more oddities become apparent. The back is a pegboard which holds a small selection of tools. To the left, a checkered grid obscures speakers. Knobs control volume There are even USB ports. On the right sits another speaker. Banana jacks let you use the analog voltmeter. Most appealingly, the indestructible Hakko 936 soldering iron has been entirely integrated into the structure of the desk.

If you press the right button on the front, the desk will reveal its last secret. It contains an entire workstation somewhere behind the array of drawers on the front. A linear actuator pushes a computer monitor up from inside the cabinet, covering the pegboard in the back. Awesome.

There is a build log, but unfortunately it’s been imageshacked and only the words remain. We think [Love Hultén] has finally managed to build a soldering station that’s welcome in every room of the house except for the garage.

Refurbishing Armored Tablets

Who can resist the insane deals on bizarre hardware that pop up on auction websites? Not [Dane Kouttron], for sure. He stumbled on Armor X7 ruggedized tablets, and had to buy a few. They’d be just perfect for datalogging in remote and/or hostile locations, if only they had better batteries and were outfitted with a GSM data modem… So [Dane] hauled out his screwdrivers and took stuff apart. What follows is a very detailed writeup of the battery management system (BMS), and a complete teardown of this interesting tablet almost as an afterthought.

First, [Dane] tried to just put a bunch more batteries into the thing, but the battery-management chip wouldn’t recognize them. For some inexplicable reason, [Dane] had the programmer for the BMS on-hand, as well as a Windows XP machine to run the antiquated software on. With the BMS firmware updated (and the manufacturer’s name changed to Dan-ger 300!) everything was good again.

Now you may not happen to have a bunch of surplus X7 ruggedized tablets lying around. Neither do we. But we can totally imagine needing to overhaul a battery system, and so it’s nice to have a peek behind the scenes in the BMS. File that away in your memory banks for when you need it. And if you need even more power, check out this writeup of reverse-engineering a Leaf battery pack. Power to the people!

Bridging the Air Gap; Data Transfer via Fan Noise

When you want to protect a computer connected to the Internet against attackers, you usually put it behind a firewall. The firewall controls access to the protected computer. However, you can defeat any lock and there are ways a dedicated attacker can compromise a firewall. Really critical data is often placed on a computer that is “air gapped.” That is, the computer isn’t connected at all to an insecure network.

An air gap turns a network security problem into a physical security problem. Even if you can infect the target system and collect data, you don’t have an easy way to get the data out of the secure facility unless you are physically present and doing something obvious (like reading from the screen into a phone). Right? Maybe not.

Researchers in Isreal have been devising various ways to transmit data from air walled computers. Their latest approach? Transmit data via changing the speed of cooling fans in the target computer. Software running on a cellphone (or other computer, obviously) can decode the data and exfiltrate it. You can see a video on the process below.

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Restoring The Groundbreaking Xerox Alto

The Xerox Alto was a minicomputer that had a lot of firsts to its name: first GUI, first Ethernet connection, and first computer to use a laser printer. This is the computer that inspired Steve Jobs to build the Lisa. And this was built all back in 1973! So when [Ken Shirriff] and a team of other old-computer aficionados got their hands on one, you know they’d get to work.

[Ken]’s blog describes the start of what’s sure to be a long journey. It mostly describes the Alto system and locates its place in computer history, but there are some interesting sidelines as well — like how [Alan Kay] also basically outlined all of the functionality of the modern laptop / tablet along the way to the Alto; it was supposed to be an interim Dynabook.

Work on this grandfather-of-modern-computers is just getting started, and [Ken] and crew are dusting off the power supplies and cataloguing memory boards. You can be sure that we’ll follow along with this restoration project, and keep you informed.

New Hard Drives for Old Computers

After a certain age, computers start to show signs that they might need to be replaced or upgraded. After even more time, it starts getting hard to find parts to replace the failing components. And, as the sands slip through the hourglass, the standards used to design and build the computer start going obsolete. That’s the situation that [Drygol] found himself in when he was asked to build a SD-card hard drive for an Atari.

The 8-bit Atari in question was a fixture of home computing in the 80s. In fact, if you weren’t on the Commodore train, it’s likely that your computer of choice was an Atari. For the nostalgic among us, a new hard drive for these pieces of history is a great way to relive some of the past. Working off of information from the SIO2SD Wiki page, [Drygol] used the toner transfer method to build a PCB, 3D printed a case, and got to work on his decades-old computer.

Resurrecting old hardware is a great way to get into retrocomputing. Old protocols and standards are worth investigating because they’re from a time where programmers had to make every bit count, and there are some gems of genius hidden everywhere. Whether you’re reworking SIO from an old Atari, or building a disk emulator for an Apple ][, there are lots of options.

Walnut Windfall Winds up in Custom Keyboard

When a neighbor decided to cut down a walnut tree, [voluhar] decided to make something of the wood. The result was this custom keyboard that combines wood and metal in a lovely and functional package.

Walnut is a wood with a rich heritage in consumer electronics. Back in the early days of TV, huge console sets were built into solid walnut cabinets and proudly displayed along with the other fine furnishings in a home. [voluhar]’s keyboard captures a little of that spirit while retaining all the functionality you’d expect. From the custom PCB to the engraved aluminum key caps, it looks like every part was machined with a CNC router. The keyboard sports satisfyingly clicky Cherry MX switches, and a few cleverly positioned LEDs provide subtle feedback on the state of the locking keys. As for the imperfections in the walnut case, we think it just adds to the charm and warmth of the finished product, which would look great on any desktop.

Wood has appeared in a couple of custom keyboards that we’ve featured before, like this all-wood version. But if you want the retro look without the wood, you could always try a keyboard built out of a typewriter.

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