Learn FPGA Programming from the 1940s

We often think that not enough people are building things with FPGAs. We also love the retrotechtacular posts on old computer hardware. So it was hard to pass up [karlwoodward’s] post about the Chip Hack EDSAC Challenge — part of the 2017 Wuthering Bytes festival.

You might recognize EDSAC as what was arguably the first operational computer if you define a computer as what we think of today as a computer. [Maurice Wilkes] and his team invented a lot of things we take for granted today including subroutines (Wheeler jumps named after a graduate student).

The point to the EDSAC challenge was to expose people to creating designs with FPGAs, particularly using the Verilog hardware description language (HDL). If you want to follow along or run your own Chip Hack, the materials are available on the Web. You can see an FPGA driving a tape punch to create souvenir tapes in the video, below.

Some of the exercises are pretty simple and that’s perfect if you are starting out. The challenge uses a board with a Lattice ice40 FPGA and the open source toolchain for Lattice we’ve covered before. In fact, we’ve even done our own tutorials on the same basic device (but not the same board). Our final project generated PWM, not paper tape.

For the record, EDSAC was awesome. The execution unit was serial and processed bits that marched in one at a time over a mercury delay line. There is quite a bit of documentation and even some simulators, so if you ever wanted to get your hands into an old computer, this one isn’t a bad one to try.

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Hackaday Links: September 17, 2017

BREAKING NEWS: APPLE HAS RELEASED A NEW RECTANGLE. IT IS BETTER THAN THE PREVIOUS RECTANGLE, WHICH WAS A LESSER RECTANGLE. SOME PEOPLE ARE UNHAPPY WITH THE NEW RECTANGLE BECAUSE OF [[CHANGES]]. THE NEW RECTANGLE HAS ANIMATED POO.

Mergers and acquisitions? Not this time. Lattice Semiconductor would have been bought by Canyon Bridge — a private equity firm backed by the Chinese government — for $1.3B. This deal was shut down by the US government because of national security concerns.

[Jan] is the Internet’s expert in doing synths on single chips, and now he has something pretty cool. It’s a breadboard synth with MIDI and CV input. Basically, what we’re looking at is [Jan]’s CVS-01 chip for a DCO, DCF, and DCA), a KL5 chip for an LFO, and an envelope chip. Tie everything together with a two-octave captouch keyboard, and you have a complete synthesizer on a breadboard.

As an aside relating to the above, does anyone know what the cool kids are using for a CV/Gate keyboard controller these days? Modular synths are making a comeback, but it looks like everyone is running a MIDI keyboard into a MIDI-CV converter. It seems like there should be a –simple, cheap– controller with quarter-inch jacks labeled CV and Gate. Any suggestions?

World leaders are tweeting. The Canadian PM is awesome and likes Dark Castle.

Way back in July, Square, the ‘POS terminal on an iPad’ company posted some data on Twitter. Apparently, fidget spinner sales peaked during the last week of May, and were declining through the first few weeks of summer. Is this proof the fidget spinner fad was dead by August? I have an alternate hypothesis: fidget spinner sales are tied to middle schoolers, and sales started dropping at the beginning of summer vacation. We need more data, so if some of you could retweet this, that would be awesome.

Remember [Peter Sripol], the guy building an ultralight in his basement? This is going to be a five- or six-part video build log, and part three came out this week. This video features the installation of the control surfaces, the application of turnbuckles, and hardware that is far too expensive for what it actually is.

TinyFPGA is a Tiny FPGA Board

We recently noticed an open source design for TinyFPGA A-Series boards from [Luke Valenty]. The tiny boards measure 18 mm by 30.5 mm and are breadboard friendly. You can choose a board that holds a Lattice Mach XO2-256 or an XO2-1200, if you need the additional capacity.

The boards have the JTAG interface on the side pins and also on a top header that would be handy to plug in a JTAG dongle for programming. The tiny chips are much easier to work with when they are entombed in a breakout board like this. Bigger boards with LEDs and other I/O devices are good for learning, but they aren’t always good for integrating into a larger project. The TinyFPGA boards would easily work in a device you were prototyping or doing a small production run.

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Lattice iCE40 FPGA Configured by Linux Kernel

The Linux kernel recently added support for loading firmware into an FPGA via the FPGA Manager Framework. [OpenTechLab] has built a driver for the Lattice iCE40 FPGA (same chip used on the iCEStick and other development boards). One attraction to the iCE40 is there is an open source toolchain called iCEStorm.

Even if you aren’t specifically interested in FPGAs, the discussion about Linux device drivers is good background. The principles would apply to other drivers, and would definitely apply if you want to write another FPGA loader.

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Compiling a $22 Logic Analyzer

On my way to this year’s Hackaday SuperConference I saw an article on EE Times about someone taking the $22 Lattice iCEstick and turning it into a logic analyzer complete with a Python app to display the waveforms. This jumped out as pretty cool to me given that there really isn’t a ton of RAM on the stick, basically none that isn’t contained in the FPGA itself.

[Jenny List] has also written about the this application as created by [Kevin Hubbard] of Black Mesa Labs and [Al Williams] has a great set of posts about using this same $22 evaluation board doing ground up Verilog design using open source tools. Even if you don’t end up using the stick as a logic analyzer over the long haul, it’ll be very easy to find many other projects where you can recompile to invent a new purpose for it.

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Hackaday Links: November 6, 2016

Here’s a life protip for you: get really, really good at one video game. Not all of them; you only want to be good – top 10% at least – at one video game. For me, that’s Galaga. It’s a great arcade game, and now it’s IoT. [justin] has been working on publishing high scores from a Galaga board to the Internet. The electronics are actually pretty simple – just a latch on a memory address, and an ESP8266 for comms.

On with the mergers and acquisitions! Lattice has been sold to Canyon Bridge, a Chinese private equity firm, for $1.3 Billion. Readers of Hackaday should know Lattice as the creators of the iCE40 FPGA platform, famously the target of the only Open Source FPGA toolchain.

The Internet of Chocolate Chip Cookies. Yes, it’s a Kickstarter for a cookie machine, because buying a tube of pre-made cookie dough is too hard. There is one quote I would like to point out in this Kickstarter: “Carbon Fiber Convection Heating Element (1300W) is more energy-efficient than traditional electric elements and heats up instantly.” Can someone please explain how a heating element can be more efficient? What does that mean? Aren’t all resistive heating elements 100% efficient by default? Or are they 0% efficient? The Internet of Cookies broke my brain.

The USB Rubber Ducky is a thumb-drive sized device that, when plugged into a computer, presents itself as a USB HID keyboard, opens up a CLI, inputs a few commands, and could potentially do evil stuff. The USB Rubber Ducky costs $45, a Raspberry Pi Zero and a USB connector costs $6. [tim] built his own USB Rubber Ducky, and the results are great.

Give Your RPi a Cool FPGA Hat

Need additional, custom IO for your Raspberry Pi? Adding an FPGA is a logical way to expand your IO, and allow for high speed digital interfaces. [Eric Brombaugh]’s Icehat adds a Lattice iCE5LP4K-SG48 FPGA in a package that fits neatly on top of the Raspberry Pi Zero. It also provides a few LEDs and Digilent compatible PMOD connectors for adding peripherals. The FPGA costs about six bucks, so this is one cheap FPGA board.

The FPGA has one time programmable memory, but can also be programmed over SPI. This allows the host Pi to flash the FGPA with the latest bitstream at boot. Sadly, this particular device is not supported by the open source Icestorm toolchain. Instead, you’ll need Lattice’s iCEcube2 design software. Fortunately, this chip is supported by the free license.

Icehat is an open source hardware design, but also includes a software application for flashing a bitstream to the FPGA from the Pi and an example application to get you started. All the relevant sources can be found on Github, and the PCB is available on OSHPark.

While this isn’t the first pairing of a Raspberry Pi and FPGA we’ve seen, it is quite possibly the smallest, and can be built by hand at a low cost.