Making Custom Silicon For The Latest Raspberry Pi

April 12, 2018 by 75 Comments

The latest Raspberry Pi, the Pi 3 Model B+, is the most recent iteration of hardware from the Raspberry Pi Foundation. No, it doesn’t have eMMC, it doesn’t have support for cellular connectivity, it doesn’t have USB 3.0, it doesn’t have SATA, it doesn’t have PCIe, and it doesn’t have any of the other unrealistic expectations for a thirty-five dollar computer. That doesn’t mean there wasn’t a lot of engineering that went into this new version of the Pi; on the contrary — the latest Pi is filled with custom silicon, new technologies, and it even has a neat embossed RF shield.

On the Raspberry Pi blog, [James Adams] went over the work that went into what is probably the most significant part of the new Raspberry Pi. It has new, custom silicon in the power supply. This is a chip that was designed for the Raspberry Pi, and it’s a great lesson on what you can do when you know you’ll be making millions of a thing.

The first few generations of the Raspberry Pi, from the original Model B to the Zero, used on-chip power supplies. This is what you would expect when the RAM is soldered directly to the CPU. With the introduction of the Raspberry Pi 2, the RAM was decoupled from the CPU, and that meant providing more power for more cores, and the rails required for LPDDR2 memory. The Pi 2 required voltages of 5V, 3.3V, 1.8V, and 1.2V, and the sequencing to bring them all up in order. This is the job for a power management IC (PMIC), but surprisingly all the PMICs available were more expensive than the Pi 2’s discrete solution.

The MXL7704, with four switching power supplies. The four symmetric gray and brown bits are inductors.

However, where there are semiconductor companies, there’s a possibility of having a custom chip made. [James] talked to [Peter Coyle] of Exar in 2015 (Exar was then bought by MaxLinear last year) about building a custom chip to supply all the voltages found in the Raspberry Pi. The result was the MXL7704, delivered just in time for the production of the Raspberry Pi 3B+.

The new chip takes the 5V in from the USB port and converts that to two 3.3V rails, 1.8V and 1.2V for the LPDDR2 memory, 1.2V nominal for the CPU, which can be raised and lowered via I2C. This is an impressive bit of engineering, and as any hardware designer knows, getting the power right is the first step to a successful product.

With the new MXL7704 chip found in the Raspberry Pi 3B+, the Pi ecosystem now has a simple and cheap chip for all their future revisions. It might not be SATA or PCIe or eMMC or a kitchen sink, but this is the kind of engineering that gives you a successful product rather than a single board computer that will be quickly forgotten.

Clive Sinclair, The Other Author

April 12, 2018 by 51 Comments

A reasonable selection of the Hackaday readership will have had their first experiences of computing on an 8-bit machine in a black case, with the word “Sinclair” on it. Even if you haven’t work with one of these machines you probably know that the man behind them was the sometimes colourful inventor Clive (now Sir Clive) Sinclair.

The finest in 1950s graphic design, applied to electronics books.
The finest in 1950s graphic design, applied to electronics books.

He was the founder of an electronics company that promised big results from its relatively inexpensive electronic products. Radio receivers that could fit in a matchbox, transistorised component stereo systems, miniature televisions, and affordable calculators had all received the Sinclair treatment from the early-1960s onwards. But it was towards the end of the 1970s that one of his companies produced its first microcomputer.

At the end of the 1950s, when the teenage Sinclair was already a prolific producer of electronics and in the early stages of starting his own electronics business, he took the entirely understandable route for a cash-strapped engineer and entrepreneur and began writing for a living. He wrote for electronics and radio magazines, later becoming assistant editor of the trade magazine Instrument Practice, and wrote electronic project books for Bernard’s Radio Manuals, and Bernard Babani Publishing. It is this period of his career that has caught our eye today, not simply for the famous association of the Sinclair name, but for the fascinating window his work gives us into the state of electronics at the time.

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Audio Hacking With The ESP8266

April 12, 2018 by 23 Comments

If you study the specifications of the ESP8266 WiFi-enabled microcontroller, you will notice that it features an I2S audio interface. This is a high-speed serial port designed to deliver 16-bit audio data in a standard format, and has its origins in consumer audio products such as CD players. It would be usual to attach a dedicated DAC to an I2S interface to produce audio, but [Jan Ostman]’s synthesiser projects eschew that approach, and instead do the job in software. His I2S interface pushes out a pulse density modulated data stream in the same manner as a 1-bit DAC, meaning that the only external components required to produce audio are a simple low-pass filter. He’s posted a video of the synth in action, which we’ve placed below the break.

The example he gives us is a basic clone of a Roland 909 drum machine, and he takes us through the code with extensive examples including MIDI. He’s using the Wemos D1 Mini board, but the same could be replicated with many other ESP8266 platforms.

We’ve featured [Jan]’s work many times before, from his minimalist Atmel-based devices through to small but perfectly-formed complete instruments.

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To Ferrule Or Not To Ferrule?

April 12, 2018 by 116 Comments

We recently posted about a spectacular 3D-printer fire that was thankfully caught and extinguished before spreading to the hacker’s house or injuring his family. Analyzing the remains of the printer, the hacker determined that the fire was caused when a loose grub screw let the extruder’s heater cartridge fall out and touch the ABS fan shroud. It ran full-on and set things on fire.

A number of us have similar 3D printers, so the comments for this article were understandably lively, but one comment stood out by listing a number of best practices for wiring, including the use of ferrules. In particular, many 3D printers connect the heated bed, which draws a lot of current, with screw terminals to the motherboard. While not the cause of the fire in the original post, melted terminal blocks are a common complaint with many DIY 3D printer kits, and one reason is that simply jamming thick stranded wire into a screw terminal and hoping for the best can result in increased resistance, and heat, at the joint. In such situations, the absolutely right thing to do is to crimp on a ferrule. So let’s talk about that.

 

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Get Your Name On The Hottest List In The Solar System

April 12, 2018 by 29 Comments

How often does NASA name a spacecraft after a living person? How often do you get to launch your name into a star? How often does NASA send probes to explore the sun? If your answer to all these questions is NEVER, then you win the honor of adding your name to an SD card bound for the center of our solar system. We’re already on the list with [William Shatner] so we’ll see you there. Submissions for the hot list aboard the Parker Solar Probe close on April 27th, 2018 and it launches in May.

The Parker Solar probe honors living astrophysicist [Eugene Parker] who theorized a great deal about how the sun, and other stars, emit energy. His work has rightly earned him the honor of seeing his name on a sun-bound probe. We even owe the term, “solar wind” to [Parker].

To draw more attention, you can have a few bits aboard this probe dedicated to you or someone you care about by adding your name to their list. Or you can send the name of your greatest enemy into the hottest furnace for millions of miles. Your call.

Even though our sun is the most prominent heavenly body, NASA hasn’t sent a probe to explore it before. They are good about sharing their models and they really know how to write standards for workmanship.

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Building The Perfect Home Router

April 12, 2018 by 43 Comments

When a favorite piece of hardware dies, it’s fairly common to experience a bit of dread. The thought that now you’ll have to go through the process of getting a replacement for the device can be very troubling, and is fraught with difficult questions. Is the hardware still available? Has it been made obsolete by something else in the time you’ve had it? But while it can be a hassle, there’s no question you can come out the other side better than you went in. Sometimes it takes the passing of an old piece of gear for you to really embrace what’s possible with the latest and greatest.

That’s exactly what happened to [Tyler Langlois]. When his trusty home router finally gave up the ghost, he was left with a couple of options. He could get another consumer router, upgrade to a enterprise-level model, or take the road less traveled and build his own router to his exacting specifications. Since you’re reading about it on Hackday, we’ll give you one guess as to which door he went through.

The blog post [Tyler] has written up about the saga of building his own router is an incredible resource for anyone who might be thinking of taking the plunge into DIY networking. From selecting the proper hardware to the nuances of getting all of the software packages installed, this is an absolute treasure trove. At the beginning of the post he mentions that the post shouldn’t be considered a comprehensive guide, but considering we’ve seen commercial hardware that wasn’t documented this well, we’d have to respectfully disagree on that point.

Some elements of his homespun may come as something of a surprise. For one, [Tyler] bucked the hive mentality and determined the Raspberry Pi simply wasn’t up to the task due (at least in part) to the single 100 Mbps network interface. He ended up going with an ESPRESSObin, a relatively niche Linux SBC that features an onboard gigabit switch in addition to a fairly hefty spec sheet. He also decided to forgo WiFi entirely, and leave the intricacies of wireless networking to a standalone access point from Ubiquity.

A router is often overlooked as just another piece of consumer kit sitting around the house, but it’s actually an excellent place to flex your creative and technical muscle. From adding a remote display to converting it into a mobile battle tank, there’s a lot more you can do with your router than stare at the blinkenlights.

Hackaday And Tindie Are Coming To London On Sunday!

April 12, 2018 by 8 Comments

Hackaday and Tindie have arrived in London at the weekend, fresh from our Dublin Unconference. Join us this Sunday afternoon, as we convene at the Artillery Arms, a pub on the northeastern edge of the City. It’s a free event, we ask though that you sign up for it via Eventbrite if you’d like to attend.

We’re following our usual Bring-a-Hack style format, so come along and hang out with members of the London Hackaday community, and if you have a project to bring along then don’t be shy as we’d love to see it. And especially if you have a Hackaday Prize entry to show then we’d particularly like to see it. You never cease to amaze us with the work you do, be it the simplest of hacks or the most technically advanced. Just one thing though, if you bring something, make sure it’s handheld or portable enough to easily sit on a pub tabletop, space may be limited.

In attendance will be Tindie’s [Jasmine Brackett] and Hackaday’s [Jenny List], as well as quite a few of our community regulars. What better way could there be to spend a spring Sunday afternoon in London?

But what if you can’t make London, and face the prospect of missing out on us entirely? Fortunately, this one is not the only meetup we have planned, we’re heading to Nottingham and Cambridge on the 18th and 19th of April, respectively, and might even squeeze in another date if we can.