Using the Newest Gen Arm, Part II

I’m a bit behind in my blog work — well, way behind, actually. I started this series back in January with the intro post.

Here’s where I am right now:

  1. I have three different sets of PCBs.
  2. One set, I took home to see if it’s possible to solder a micro-BGA at home. (As someone working at a car manufacturer might want to see if they could balance a crankshaft at home, for fun)
  3. Two sets, from our partner, Sunstone Circuits, are here in my desk with parts, ready to go through our machines.

After I’ve got all three sets built, I’ll have them x-rayed to see how they look under the hood. Finally, I’ll solder through-hole headers on and fire up the chips to see if the shared escape system works.

Here’s one of the boards without access to the inner pads:

And, here’s the shared escape:

The main concern I have is that Reset is on one of the inside pins (B4). I’m not sure if I can get the chip to a state where it will operate properly without unobstructed access to reset.

The routing I’ve chosen is probably the only possible option for reset. Pin A4, right above, is used for the single-wire debug (SWD) clock. I’m assuming that can’t be shared. B5 is Vdd, so that’s out. It might be possible to go down. C4 defaults to one of the crystal pins, and D4 defaults to a disabled state.

In the route I’ve chosen, B3 is an ADC input, so it should start out high-impedance, and therefore not interfere. A3 defaults disabled, so it won’t get in the way.

Next step: solder time!

One other thing – The images above show non-solder mask defined (NSMD) pads. Those are standard for BGAs 0.5mm pitch and higher. This part is 0.4mm pitch. Some manufacturers recommend solder mask defined pads (SMD) for 0.4mm and smaller. I’m actually testing several pad styles: SMD, NSMD and solder mask opening = copper.

Duane Benson

Run it up the flag pole and see who solders

Bragging Rights

I want to call attention today to a great new contest for designers being run by Sunstone Circuits.

The contest works like this: From now until Dec. 16, design engineers can share their PCB-related design success stories online at Sunstone’s website.

Friends and others to the site can vote for the best project. All entrants and voters are entered into a sweepstakes to win a series of prizes, ranging from gift cards to an iPad.

It’s a great way for designers talk (and yes, perhaps, brag) a bit about what they do. And while Sunstone certainly benefits from the exposure, I’m glad to see a company taking steps to highlight the remarkable things designers can do.

DfM Chat

Who better than a fabricator to explain design for fabrication?

Join Sunstone Circuits CAD/EDA manager Nolan Johnson this Thursday for a one-hour chat on DfM. Trained as a software engineer, Johnson wrote applications software for Mentor Graphics before transitioning into technical marketing roles. He managed Mentor’s OEM verification development projects, including Dracula and CheckMate. Johnson then concentrated on operating technical training centers for semiconductor manufacturing and telecom analysis equipment at both Electro Scientific Industries and Tektronix.

At Sunstone Circuits, Johnson has assisted in the many successful initiatives of its core product line, including an integral role in the development of the PCB123 design software, including enhancing the software’s schematic functionality and Live BOM (Bill of Materials).

Nolan’s chat takes place May 10, 2 to 3 pm Eastern time at PCB Chat. There is no charge to participate.

Top 10 Things To Do In 2012

Unless you’ve managed to live off the grid for the last five years, you know that the Mayan calendar has predicted the end of the world on Dec. 21, 2012. Ignoring all conventional wisdom, centuries of scientific knowledge and the fact that the Mayan community doesn’t even believe it, I feel compelled to list key electronics things that everyone should see or do in this last year before the end of the world. Because, you know, just in case…

Here are the top 10 things to look into or do in 2012 before the end of the world on December 21, 2012:

0b0000.0000: Build something open source. It’s amazing what is available. Back in the heyday of hobby electronics, it was easy to find projects in magazines such as “Popular Electronics.” You could get kits from Heathkit of RadioShack. But, for the most part, all of those things went away. With Open Source, you can build an almost unlimited variety of gadgets. What’s more, you can taylor your build to your experience level. If you want to do it all, just get the files, fab your boards, buy your parts and solder it up. If you’re less ambitious, buy a complete kit. If you’re even more ambitious, mod the design and post it up for the community.

0b0000.0001: While you’re out fiddling with Open Source, get ahold of a Beaglebone. It’s Ti’s second take on open source hardware. The original Beaglebard was and is a great way to get to know their OMAP processors, both in therms of programming it and in terms of designing a PCB for it. The Beaglebone is an easier to use, easier to expand, but not quite as powerful adjunct to the Beagleboard.

0b0000.0010: Try out some new CAD software. Sunstone released PCB123 version 4 in 2011 and Element14 released EagleCAD version 6. Check them out and see if they do what you need. Both are good economical ways to get into circuit design and layout. PCB123 doesn’t cost anything initially. It sends your boards through Sunstone and they earn their rent that way. Eagle has a tiered pricing model, starting at a small non-commercial version for free and stepping up to a full-feature professional system.

0b0000.0011: Try out some newer technology. I’f you’ve always been intimidated by QFN or micro BGA packages, go ahead and give it a try. They’re more difficult at first, but once you’ve got the tricks down, you get access to a slew of new components that only come out in those form factors. Check out some guidelines on QFN use.

0b0000.0100: Look at space pictures. There are a number of probes up running around our solar system these days, and one on the verge of leaving it. Hop on over the or and see what’s going on. There’s a probe orbiting an asteroid, new ones off to Jupiter and Mars, one orbiting Mercury, some new space telescopes and more. There’s just a lot going on out there right now. You can even leave your computer, go outside and look up at the sky for real.

0b0000.0101: Try and make something really, really small. For my part, I’m taking a little two-motor robot brain I’ve built and an trying to see just how small I can make it. You have to think differently when size is a prime consideration. Factors that didn’t matter much suddenly become design critical. It might be an opportunity to freshen your brain up a bit (although, if the world is ending on 12-21-12, having a fresh brain may not be all that important).

0b0000.0110: Go back in time. Get a 2N2222 or 2N3907, or both. See if you remember how to build basic common base, common emitter and common collector amplifiers. No. Don’t go to Wikipedia. Try to do it from memory. I’m sure you built all of them waaaay back in your school days. Next try to build some basic logic gates with transistors. After you’ve done that, see if you can build up a RSIC processor and a 512 Mbyte RAM block using only discrete transistors and passives. As your final assignment, use the computer system you built to calculate the first 100,000 prime numbers.

0b0000.0111: Take your most recent resume and replace all of the letters, spaces, tabs and line ends with their hex values. Submit it in that form for your dream job. Then sit back and wait for the hiring manager to bow down to your superior skills. Since the world is ending, it really won’t matter that the first person to see the resume thought it was gibberish and round-filed it.

0b0000.1000: Introduce you kids (if you have them) to robots. Get them started down the technical path early; both boys and girls. And, if you have daughters, make sure they don’t get discouraged by peer pressure or whatever pressure. If they are interested in a technical career, don’t let the world around them pressure them out of it. If you don’t have kids, build some robots yourself and introduce your pets to them. See who ends up chasing whom around the house.

0b0000.1001: Finally, ignore all of this. Come on. Really? The Mayans knew when the world would end? Even I don’t know that. Although, there was that John Cusack movie. And I’ve read about it on the Internet and everyone knows that if you read it on the Internet, it must be true…

Duane Benson
See you all on the other side

Faster, Chug-a-Chug … Faster, Chug-a-Chug …

Ever long for the days when you could lazily send out your files to get boards fabbed and a prototype assembled and then have a leisurely couple of weeks waiting for it all to completed and returned? Well, we’re not going to help you get back to that. In fact, we try to do the opposite. Let’s make everything speedier and speedier. I hope that’s okay.

Screaming Circuits’ PCB fab partner, Sunstone Circuits just added in a bit more to that end. Back in the old days, if you needed PCBs fabbed in 24 hours, you had to stick with two-layer boards. Not any more. They recently started offering four-layer PCBs fabbed in 24 hours in their PCBexpress quick-turn service. No rest for the weary. That’s especially cool if you’re having signal integrity problems and need to add in a ground and/or power plane layer.

Duane Benson
If by approaching the speed of light, time speeds up for you,
does time slow down for you as you approach “stopped”?

Reminders are Sometimes Good

I was recently reading an article on another website that caused me to reflect on where we’ve been and how far we’ve come in this industry. The article covered a design engineer’s experience with modding a board back in the 80s and being required to ship the board with the mods instead of getting new ones made properly.

Back in the late 80s and early 90s, I worked for a company that designed and built business-oriented displays. One of the products was particularly troublesome to get going and the first production versions shipped with something like 24 different mods. If the company had respun the boards, we would have added at least a month to the schedule and payed somewhere in the range of $20,000 to $40,000. If I recall correctly, one of the biggest problem areas was the PLL (phase-locked loop). We were over-driving the parts a bit and that made all of the support passives and the layout that much more critical. Not smart, but I guess that came from one of those “cost-benefit” analysis-type things.

Contrast that today where you can get a new set of boards from a PCB fabrication like in a few days for a few hundred dollars, get the parts from Digi-Key overnight and have us (Screaming Circuits) assemble them in a day or two.

Of course, it’s a bit of a double-edged sword. Like when faxes and later email came along. Written communications cycles that used to be measured in days became measured in hours and minutes. The expectations changed. Can you imagine writing a letter to a company and waiting a couple of weeks to get a response?!! That’s the way it used to be.

In the same vein, we at Screaming Circuits (and some others too) have changed the prototype cycle expectations. Can you even imagine finishing your layout and waiting four to six weeks for assembled boards to come back? Yikes! But that’s what it used to be like. We’re all making things go faster and faster. It keeps getting faster and it won’t slow down. But that’s good, because time = money, so less time building = less money spent and more time selling = more money earned. Right?

Duane Benson
I… Just… Need… More… Coffee… NOW!!!!

Circuit Design ECOsystem

Years and years ago, I was a product manager at In Focus, the projector manufacturer. It was a great time to be in the display industry. New technology was being invented left and right (and center and back, and some over in that far corner too). Competition was still reasonably light and we were ahead of most of it.

It was always interesting to take one of the early overhead projector-style displays through airport security. Laptops were rare at the time, let alone a big clear display that looked like a see-through touch-pad computer, but without the computer. But that’s not the point.

Back in our engineering department, we had the electronics engineers, a few folks to work on firmware, a layout specialist, documentation specialists to deal with all the documentation (duh), purchasing people to buy the parts and PCBs, technicians build up the prototypes, manufacturing people to get the pre-production and production going. And here,s the contrast today. Quite a few engineers I talk to these days have to do all of those jobs except final production. That wouldn’t be too much of a problem except that while all of those jobs were being assigned to the engineer, everything got more difficult. Parts got smaller, timelines shrank, competition got more fierce, clock speed increased and a lot of formerly company functions, got out-sourced. It’s a lot of work and a lot of ground for that engineer to navigate.

A handful of companies — Digi-Key, NXP, National Instruments, Sunstone Circuits and Screaming Circuits (my company) — have gotten together to form the Circuit Design ECOsystem; a cross-company organization designed to help that design engineer get a design from inside the brain to the market.

NXP makes components and is creating library components for the CAD software made by National Instruments and Sunstone. Sunstone allows quoting and ordering of Screaming Circuits assembly service on their website and Screaming Circuits does the same with Sunstone PCB fab. Digi-Key is working to improve the data-flow to Sunstone’s PCB123 CAD and streamline the parts procurement process to Screaming Circuits.

It’s still early in the process, but the idea is to take the, now fragmented, design to manufacture process and make it easier for the electrical engineer to get through – to remove roadblocks, add in new services and improve communications to make it easier to produce a quality product.