Crawl, Walk, Run: A Starter CPU

March 25, 2016 by Al Williams 3 Comments

Last time I talked about getting started with CPU design by looking at older designs before trying to tackle a more modern architecture. In particular, I recommended Caxton Foster’s Blue, even though (or maybe because) it was in schematic form. Even though the schematics are easy to understand, Blue does use a few dated constructs and you probably ought to build your take on the design using your choice of VHDL or Verilog.

In my case, my choice was Verilog. You can find my implementation of Blue on Opencores.org. I made quite a few changes to Foster’s original design. For example, armed with semiconductor memory, I managed to get all instructions to operate in one major cycle (which is, of course, 8 minor cycles). I also modernized the clock generation and added some resources and instructions.

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Kestrel Computer Project

March 25, 2016 by Brandon Dunson 29 Comments

Many successful large-scale projects don’t start out large: they start with a small working core and grow out from there. Building a completely open-source personal computer is not a weekend project. This is as much a retelling of events as it is background information leading up to a request for help. You’ll discover that quite a lot of hard work has already been put forth towards the creation of a completely open personal computer.

When I noticed the Kestrel Computer Project had been submitted via the Hackaday tips line I quickly tracked down and contacted [Samuel] and asked a swarm of questions with the excitement of a giddy schoolgirl. Throughout our email conversation I discovered that [Samuel] had largely kept the project under the radar because he enjoyed working on it in his down time as a hobby. Now that the project is approaching the need for hardware design, I posed a question to [Samuel]: “Do you want me to write a short article summarizing years of your work on Kestrel Project?” But before he could reply to that question I followed it up with another: “Better yet [Samuel], how about we tell a more thorough history of the Kestrel Project and ask the Hackaday community for some help bringing the project home!?”
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5 Wide And Tall Monitors With Hacked Bezels For Wall Of Awesome

March 20, 2016 by Richard Baguley 17 Comments

If two is better than one, what about five? [Omnicrash] has posted a nice analysis of his monitor setup, which uses 5 portrait mounted monitors side-by-side. To minimize the bezel size between them, he removed the casing and built a custom stand that placed them all closely together for a surround viewing approach. He’s been using this setup for a couple of years and has posted a nice analysis of making it work for multiple purposes. On the upside, he says it is awesome for gaming and watching videos.

On the downside, NVidia’s drivers and multi-monitor setup are a pain, and some tasks just didn’t work with the bezels. He couldn’t, for instance, run a standard-sized remote desktop screen anywhere without having the bezel get in the way. So, with large, hi-res monitors now getting cheaper, would he do it again? “If I had to do it all over again nowadays however I’d probably just go with a single 34″ ultra-wide for about the same price..though I probably wouldn’t be able to help myself and would eventually be adding at least one on top and 2 in portrait on the side.”

Thanks For The Memories: Touring The Awesome Random Access Of Old

March 8, 2016 by Al Williams 41 Comments

I was buying a new laptop the other day and had to make a choice between 4GB of memory and 8. I can remember how big a deal it was when a TRS-80 went from 4K (that’s .000004 GB, if you are counting) to 48K. Today just about all RAM (at least in PCs) is dynamic–it relies on tiny capacitors to hold a charge. The downside to that is that the RAM is unavailable sometimes while the capacitors get refreshed. The upside is you can inexpensively pack lots of bits into a small area. All of the common memory you plug into a PC motherboard–DDR, DDR2, SDRAM, RDRAM, and so on–are types of dynamic memory.

The other kind of common RAM you see is static. This is more or less an array of flip flops. They don’t require refreshing, but a static RAM cell is much larger than an equivalent bit of dynamic memory, so static memory is much less dense than dynamic. Static RAM lives in your PC, too, as cache memory where speed is important.

For now, at least, these two types of RAM technology dominate the market for fast random access read/write memory. Sure, there are a few new technologies that could gain wider usage. There’s also things like flash memory that are useful, but can’t displace regular RAM because of speed, durability, or complex write cycles. However, computers didn’t always use static and dynamic RAM. In fact, they are relatively newcomers to the scene. What did early computers use for fast read/write storage?

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Ultimate Battery Backup Mod

March 5, 2016 by James Hobson 90 Comments

Unless your main workstation is a laptop, you’ve probably got a APC or similar battery backup kicking around. But have you ever thought of modifying it to make it a bit more useful? After all, it can be used as a useful DC power supply…

[The 8-Bit Guy] shows us how he modified his APC to include a voltage readout, and direct DC output jacks. As it turns out you can get a lot more battery life if you’re not using the built-in pesky AC/DC power inverter! Stick around after the break for a very informative video on how he did it.
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Odroid C2 Bests Raspberry Pi 3 In Several Ways

March 2, 2016 by Jenny List 139 Comments

It’s been a big week in the world of inexpensive single board computers, and everyone’s talking about the new Raspberry Pi 3. It blows away the competition they say, nobody can touch it for the price.

Almost nobody, that is.

With a lot less fanfare on these shores, another cheap and speedy 64-bit quad-core ARM-based SBC slips onto the market this week, Hardkernel’s Odroid C2. And looking at the specification it seems as though the Pi 3 may be given a run for its money. Like the BCM2837 in the Pi 3 its Amlogic S905 SoC is a quad-core ARM Cortex-A53, but the C2’s 2GHz clock speed gives the raspberry to the 1.2GHz of the Pi 3. There is twice the RAM of the Pi 3 at 2Gbytes, and the onboard Mali-450 GPU can deliver 4K video.

Unlike the Pi 3 there is no wireless or Bluetooth on board, but the C2 has a Gigabit Ethernet port which is wired directly into the SoC. Compared to the Pi 3’s 100 megabit port which suffers through being on a USB interface, that’s likely to be very quick.

Storage can be a choice of either the usual micro SD card or eMMC. Given that the two boards share a very similar form factor it is no surprise that they have very similar GPIO capabilities, however it is worth noting that the C2 has a built-in analog-to-digital converter. As to operating systems, the C2 can run Ubuntu 16.04, or Android Lollipop.

Of course, we’ve seen so many boards touted as Pi-killers, and like all those also-ran tablets touted as iPad killers a few years ago we’ve never heard of most of them again after a brief moment of chatter. They look so good on paper but the price always lets them down.

The C2 could just escape that fate though, its $40 price point is very close to that of the Pi 3. Setting aside for a moment how much shipping and customs might cost for a package from Korea, that sounds interesting to us.

Why might you buy a C2 then, and why might you buy a Pi 3? That the C2 has a much faster processor is beyond doubt. This and its faster wired networking would make it a much more interesting prospect for anyone whose work involves network-attached data processing. But even though a USB wireless network adaptor can be had for only a few dollars the Pi 3’s onboard wi-fi and Bluetooth makes it much more attractive to a home user or someone using a computer on a platform unfettered by wires.

However impressive the C2 may be it is overwhelmingly likely that the Pi 3 will outsell it many times over. This will not just be due to the massive publicity advantage achieved by the Pi Foundation, but the huge ecosystem of hardware and software developers that have made the Pi boards perform to the limit of their abilities in all directions. If you don’t mind forgoing that support though, you could just find that the board from Korea gives you enough extra bang for your buck to make having it on your bench worthwhile.

We’ve followed the Odroid products from the start here at Hackaday. The C2 is just the latest of a procession of boards from Hardkernel, and we’ve featured a few projects that include them. Theirs is always the name at the top of the list when the subject turns to Raspberry Pi competitors, perhaps with the C2 they’ve got a winner.

Our thanks to [Derrick].

Floppy Drive Hides SD Card Reader

February 28, 2016 by Bob Baddeley 23 Comments

[gilmour509] posted a thorough gallery of a new custom-built computer and case made to look like a 1995 IBM Aptiva. While the whole build is impressive, the most clever part involves a 3 1/2″ floppy disk that hides an SD card and works like a regular USB flash drive when inserted into the floppy drive.

He makes use of the fact that floppy disk edge card connectors have the same spacing as SD cards. Add in a hacked USB card reader, some careful cutting and assembly, and [gilmour509] has a very convincing floppy drive with gigabytes of space.

The best part is that with everything put together, the floppy disks and floppy drive look completely unmodified. He even made the file explorer icon show a floppy drive.

The faux-Aptiva gallery includes the full build, but skip to about 2/3 down to see the floppy SD card section.

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