Al Williams Tells All In The Logic Simulation Hack Chat

March 4, 2022 by Tom Nardi 1 Comment

The list of requirements for hosting one of our weekly Hack Chats is pretty short: you’ve got to be knowledgeable, passionate, and above all else, willing to put those two quantities on display for a group of like-minded strangers. Beyond that, we’re not too picky. From industry insider to weekend hobbyist, high school dropout to double doctorate, if you’ve got something interesting to talk about, we’re ready to listen.

But in casting a such a wide net, we occasionally forget that we’ve got a considerable collection of potential hosts within our own worldwide roster of contributors. Among this cast of characters, few can boast the same incredible body of knowledge as Al Williams, who was able to pencil in some time this week to host the Logic Simulation Hack Chat.

Or at least, that was the idea. In reality the Chat covered a wide range of topics, and was peppered with fascinating anecdotes pulled from Al’s decades of experience in the field. Though to be fair, we expected no less. He was building hardware before many of us were born, and can take credit for designs that have been at the bottom of the ocean as well as launched into orbit. He’s been writing about it just as long too, with articles of his appearing in iconic print magazines such as Dr. Dobb’s Journal.

Al has seen and done so much that he still surprises us with the occasional nugget, and we’ve been working with him for years. It was only a week or two back that he started a story with “Back when I used to manage a gas pipeline…” in the middle of a conversation about utility metering.

Of course, that’s not to say some technical discussion didn’t sneak in there from time to time. Sure Al’s recollection of how they used to literally crawl over the schematics for the 68000 back at Motorola might stick out as a particular high point, but he also explains his personal preference for vendor-specific software tools over their more generic open source counterparts. He also draws comparisons between hardware description languages (HDLs) like Verilog and parametric CAD tools such as OpenSCAD in the way that they help model complex relationships in ways that can’t be easily done by more traditional means.

At one point the conversation lingers on the design and production of application-specific integrated circuits (ASICs), and how they compare to field-programmable gate arrays (FPGAs). Traditionally ASICs have been out of reach for the hobbyist, but with the recent collaboration between Google and SkyWater Technology to create an open source process design kit (PDK), they’re now within the capabilities of a dedicated individual. Matt Venn spoke on the topic during Remoticon 2021, and it’s good to see more folks in the community openly discussing the possibilities of custom silicon designed by hackers.

From there, things start really getting wild. From dreaming of virtual reality circuit simulators that let you fly amongst your creations like in Tron, to salivating over high-end technologies such as reflective memory, this Chat really runs the gamut. But then, that’s sort of why we hold them in the first place. Whether you actively participate or are just along for the ride, the Hack Chat gives everyone in the community a chance to gather around a virtual water cooler with fascinating characters that you won’t find anywhere else.

The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.

FPGA Starter Videos To Help Soften That Learning Curve

February 17, 2022 by Dave Rowntree 8 Comments

Digi-Key have been producing YouTube videos for a number of years now, and if you weren’t aware, they’re definitely worthy of some viewing time. The playlist we’re highlighting here is a pretty good introduction to FPGAs, specifically those supported by open source tools, with low cost hardware. If you’ve always wanted to get into hacking FPGA platforms, but don’t know where to start, this is going to be a big help. After first covering what an FPGA is and is not, and why you want to use one, [Shawn Hymel] dives in to the toolchain.

We’re really lucky that the bitstream for the Lattice iCE40 was reverse engineered by the super talented Claire (née Clifford) Wolf (AMP hour interview) which enabled the project ICEstorm toolchain to be created. Leveraging Yosys for synthesis and logic mapping, Icarus verilog coupled with GTKwave for simulation, netpnr for place and route and finally the project ICEstorm bitstream tools for packing into iCE40 format and loading onto the hardware. The whole toolchain flow is managed by APIO for simplicity, that is, provided your FPGA board is supported!

Of course, [Shawn] is using the low cost (for an FPGA) ICEStick by Lattice for this tutorial series, and they’re currently hard to get (you know why by now!) but, there are many other boards you could use. If you want to play with applications coupling a ARM micro to an FPGA, then the excellent BlackIce Mx is an option, but there are many other boards now with an decent micro nestled next to an FPGA and a few peripherals for convenience.

We should mention here, that project ICEstorm and the iCE40 is not the only show in town. Project Trellis has had our eye for a while, which targets the more complex Lattice ECP5 device. Yosys and friends do support more architectures, but the available flows usually require at least some vendor tool support at this time (looking straight at you, Xilinx) but as more devices get decoded, the open source tools will grow, and we will bring you that news!

What’s nice about this Digi-Key YT series, is that it doesn’t just cover the basic toolchain flow, then drop you in at the deep end of a big learning curve. There are videos covering subjects such as finite state machines (FSMs), test-benching and simulation, using embedded (block) memories, PLLs, harder subjects like dealing with metastability and clock-domain crossing (OK, he covers one technique – there’s more than one way to skin that particular cat) before finally looking at soft cores like the RISC-V. Lots to learn, and pretty well executed if you ask us! A Github version is available, for those who can’t stand watching the videos!

Continue reading “FPGA Starter Videos To Help Soften That Learning Curve” →

Tilting At Windmills Nine Bits At A Time

February 11, 2022 by Al Williams 18 Comments

In the old days — we are talking like the 1960s and 1970s — computers were often built for very specific purposes using either discrete logic or “bit slice” chips. Either way, more bits meant more money so frequently these computers were made with just enough bits to meet a required precision. We don’t think that was what was on [Mad Ned’s] mind, though, when he decided to implement a 9-bit CPU called QIXOTE-1 on an FPGA.

Like many hobby projects, this one started with an FPGA board in search of a problem. At first, [Ned] had a plan to create a custom computer along with a custom language to then produce a video game. A quick search on the Internet led to that being a common enough project with one guy that we’ve talked about here on Hackaday before knocking it out of the park.

[Ned] then thought about just doing a no-software video game. Too late to be the first to do that. Not to be deterred, he decided to duplicate the PDP-8. Whoops. That’s been done before, too. Wanting something original, he finally decided on a custom CPU. Since bytes are usually — if not technically — 8 bits, this CPU calls its 9-bit words nonads and uses octal which maps nicely to three digits per nonad.

This first post talks about the story behind the CPU and gives a short overview of its capabilities, but we are waiting for future posts to show more of what’s behind the curtain in what [Ned] calls “Holy Nonads, Part 010.”

The downside to doing a custom CPU is you have to build your own tools. You can always, of course, duplicate something and steal your toolchain. Or go universal.

DE10-Lite-Ful FPGA Dev Board Hack Plays The 1981 Classic Defender

January 8, 2022 by Ryan Flowers 6 Comments

We’re not sure what the assignment was, but the results of [Garret Carter]’s homework for his Digital System Design class at Tennessee Tech couldn’t help but capture our attention. Below the break you can see what [Garrett] describes as a “simplified stylized version” of the 1981 arcade hit “Defender”.

With the goal of keeping the price low but keeping performance as high as possible, [Garrett] set forth to program the DE10-Lite FPGA development board in VHDL. The results are convincing, and while not perfect, came in under budget.

The DE10-Lite board gave [Garrett] the opportunity to get even more creative, using the dev board’s onboard switches, buttons, 7-segment LED’s and accelerometer to full effect. In this case, the dev board is not only the game, but also the controller and status display. A very neat hack indeed!

If you want to make your own, you can get the full project details at [Garrett]’s Github page. And [Garrett], we don’t know what marks your professor will give, but we give you an A+, would definitely play again.

While FPGA development boards aren’t necessarily inexpensive, our own Jenny List shows where you might be able to find a used but workable FPGA board for a fraction of the cost, If you know where to look.

Continue reading “DE10-Lite-Ful FPGA Dev Board Hack Plays The 1981 Classic Defender” →

A 1981 Centaur pinball table rebuilt into a coffee table.

Clear Off The Coffee Table, It’s Pinball Time

December 28, 2021 by Kristina Panos 10 Comments

Like many of us, [BuildXYZ] has always wanted to own a pinball machine, but doesn’t have the space to justify buying such a big and heavy toy. But where there’s a will, there’s a way. [BuildXYZ] figured that if they could build a pinball machine into a coffee table form factor, they’d be at least halfway to justification.

[BuildXYZ] didn’t choose just any pin. After doing a bunch of research, they settled on 1981’s Bally Centaur because it’s an early solid-state machine, and it’s one of the best. It has no secondary playfield levels to deal with, making it much easier to do this project.

Where do we even start to describe this beautiful labor of love? There are too many details to list, but know that it seems to be equal amounts of restoration work and custom work that brought this table together. The build video after the break is definitely worth your time, and you’ll gain a much better appreciation of the amount of time that went into this, from the custom score decoder chip built on an FPGA to the 3D printed replacement drop targets and new acrylic bits to replace the yellowing ones from the playfield.

Continue reading “Clear Off The Coffee Table, It’s Pinball Time” →

6502 Goes FPGA (Again)

December 26, 2021 by Al Williams 35 Comments

While there has been no shortage of FPGA-based recreations of classic processors, we always enjoy seeing a new approach. Last month [Some Assembly Required] took on the challenge to recreate a classic computer from the ground up and started with a 6502 implementation in Verilog. You can see in the second video below that he’s made good progress and there are apparently more videos to come.

The ROL instruction is the subject of the second video. We liked the approach of looking at what the instruction does and how many cycles it takes on different variants It is always good to make sure you know exactly what you are trying to accomplish before you get started.

Continue reading “6502 Goes FPGA (Again)” →

Observing A Plant’s Vascular System With X-Ray Video

November 23, 2021 by Mike Szczys 2 Comments

[Ben Krasnow] has a knack for showing us what’s inside of things while they’re moving. This week’s Applied Science experiment has him making time-lapse X-ray videos of things. This plant’s vascular system is just one of a few examples, the others being a dial clock and the zoom lens on a DSLR.

The trick here is having an X-ray sensing panel that can be reused. It takes around five seconds of exposure to grab each 40×40 cm frame which are then assembled back into video.

Now watching mechanisms move is cool — [Ben’s] video back in 2015 to show what a phonograph needle in the groove of a vinyl record looks like under a scanning electron microscope is still one for the coolest “camera tricks” we’ve ever seen pulled off. But watching the vascular system of a plant function is the recipe for one of those ah-ha educational moments, so we hope that 7th-grade biology teachers everywhere will find their way to this video.

The apparatus is described in great detail, but regular Hackaday readers will most likely want to focus in on the teardown of the X-ray panel, which [Ben] describes as a giant digital camera sensor tuned for receiving the X-rays. The source is a 50 kV 1 mA tube that he compares to what is used at the dental office. (Obviously this requires forethought to ensure his automated time-lapse setup will fail safe with the X-ray tube.) A Cyclone III FPGA drives the panel, communicating with the sensor array via two Ethernet interfaces.

A friend sent a the broken panel to [Ben] and he was able to easily repair a MOSFET that got knocked out of place. [biluni] shows up in the comments of this video, sharing his recollection from working in the industry 15 years ago that a panel like this would have cost $150k! But considering the stellar resolution, and repeatable use, it sure as heck beats the old film process.

Continue reading “Observing A Plant’s Vascular System With X-Ray Video” →