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John McMaster
@johndmcmaster 4 years, 5 months ago 1029 views

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#RaspberryPiPico silicon teardown time!

Board as received optical + x-ray images

Inspecting package. X-ray shows bond wires easier after removing thermal slug

Thermal slug removed w/ HCl + H2O2

Decapped to show copper bond wires connecting die to package pins. Initially used only nitric acid which destroyed copper bond wires (last image). Fixed by switching to mixed nitric + sulfuric acid

Zoomable top metal die image: https://t.co/MXqDBvNgqG

@Raspberry_Pi marking it's turf

B0 => chip revision. On every layer? A chip I worked on did this and unfortunately when we fixed a bug on a *different* metal layer we didn't want to remake the masks with the text. Thus "B1" chips were mislabeled as B0!

M8 => eight metal layer chip. Higher metal layers are coarser to carry more power and reduce manufacturing costs. You can also see M7 and M6 marked

Copper bond wires were eaten by nitric acid leading little dimples where they used to be attached to the bond pads

Several unused power pads. Possibly breaks out internal core voltage for debug / test

Time lapse etching chip layers

This area wasn't 100% etched, leading to vibrant blue/purple from SiO2 thin film interference

1) 20x air vs 2) 60x oil objective: 60x has higher resolution but lower depth of field, making the image appear different. Ex: although the lower left splotch is large, it's only visible in the 60x image. I might take SEM images later for better resolution

Transistors arranged into standard cells form the majority of the digital logic. This includes both the CPU and the digital portion of most peripherals

A few different I/O showing logic, ESD protection, etc between the top metal and transistor layer. A number of different I/O IP blocks are used. Would be interesting to match them up to the datasheet for analog functionality like ADC, USB, etc

Memory, probably the boot ROM

SRAM is scattered throughout the die. By analyzing the memory sizes and comparing to the datasheet it might be possible to guess what some of these are for

CMP fill is added to unused areas to keep polishing more even when preparing for the next layer. As such, it looks like it was omitted on M8 (top metal) but is found on other layers

That's all for now. Hope you enjoyed and let me know if you want more information on something!

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Some people really benefit from hearing advice that everyone knows, for the same reason we keep schools open despite every subject in them having been taught before.

In that spirit, here's some quick Things Many People Find Too Obvious To Have Told You Already.

Your idea is not valuable, at all. All value is in the execution. You think you are an exception; you are not. You should not insist on an NDA to talk about it; nobody serious will engage in contract review over an idea, and this will mark you as clueless.

Technologists tend to severely underestimate the difficulty and expense of creating software, especially at companies which do not have fully staffed industry leading engineering teams ("because software is so easy there, amirite guys?")

Charge more. Charge more still. Go on.

The press is a lossy and biased compression of events in the actual world, and is singularly consumed with its own rituals, status games, and incentives. The news necessarily fails to capture almost everything which happened yesterday. What it says is important usually isn't.

Companies find it incredibly hard to reliably staff positions with hard-working generalists who operate autonomously and have high risk tolerances. This is not the modal employee, including at places which are justifiably proud of the skill/diligence/etc of their employees.

ashkan soltani
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BREAKING: @CommonsCMS @DamianCollins just released previously sealed #Six4Three @Facebook documents:

Some random interesting tidbits:

1) Zuck approves shutting down platform API access for Twitter's when Vine is released #competition

2) Facebook engineered ways to access user's call history w/o alerting users:

Team considered access to call history considered 'high PR risk' but 'growth team will charge ahead'. @Facebook created upgrade path to access data w/o subjecting users to Android permissions dialogue.

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4) Docs also shed more light into @dseetharaman's story on @Facebook monitoring users' @Onavo VPN activity to determine what competitors to mimic or acquire in 2013.

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Java was first released in mid-1995, just 6 months before JS.

By 98, when I went to college, Java was already used for all the first level courses in the CS program.

How did it catch on so quickly (just 3 years) to shift university curriculum, which is usually so slow/behind?

I wonder why Java was so respected and JS was not? Why/how was Java already seen as such a stable and mature language?

Not just Java, other languages (like python) were also released around/near 95, and also seemed to get to "mature" respect status. much quicker.

I bring all this up because my impression of Java in 98 was that it had been around "forever" (as had C++ first developed in 79, but not standardized until 98!), but that's not. true at all. These were all new languages around the same time.

I'm sure the language designs had different merits, and the target applications meant a different perception and reception, but...

it sure seems like the industry (and academics) just decided Java and C++ were the stable mature ones and langs like JS were toys.

BTW, before you assume JS was nascent/immature b/c the web wasn't much of a thing yet, remember that JS was actually released as LiveScript on the server before it was released in a browser. So "server-side JS" was always part of the story, not just Node 15 years later in 2009.

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🙋🏾‍♀️ In 2011, I was hired into my first junior role in tech @Groupon

👩🏾‍💻 By 2020, I was headhunted into a VP role in a global tech company @Brandwatch

🤖 I achieved this progression in less than a decade, without ANY coding skills

🔮 How did I do it?

*a thread*

🤓 I established a track record of results.

💪🏾 No magic formula can replace hard work: do your job well & hit all the targets you are set.

😬 When you're struggling, ask for help so you can stay on track to get results, or collaboratively adjust targets.

🎨 I stayed creative.

🧙🏿‍♀️ When challenges arose I was bold enough to try new solutions. Not everything worked, but constantly trying produced valuable innovations.

🧠 I was proactive in finding new, better ways to get the job done.

🤩 I was a self-promoter. I recorded my achievements & ensured they were mentioned in any performance / compensation reviews.

😎 I put myself forward for any opportunities to gain recognition e.g. speaking opportunities or awards.

👀I actively worked on gaining visibility.

🙂 I was myself. Some say you need to be ruthless to succeed. I don't buy it. I'm a nice person so I'm nice at work, too.

❤️ I didn't fake it. I always acted on my values, and spoke up when something didn't feel right. I showed integrity.

🤗 I was a team player. To everyone.

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I am grateful to @slatestarcodex for taking the time to respond to my critique of technocracy. There is a lot there to respond to and in general I think the exchange speaks for itself. However, I think there are few points where clarification is important for the exchange to be

productive, which I'll briefly address here. I suspect many fellow travelers (e.g. @audreyt @dsallentess @JohnnieM @MichelleRempel @VitalikButerin @mds49) will find the exchange fairly ironic/revealing. I'll post this as a response on this blog as well.

1. Let me start with concessions. There are many points where @slatestarcodex correctly highlights various areas where my grasp of beliefs and facts are limited or wrong, especially in the depth of my grasp of the views of the rationalist community.

I freely admit that there are serious limits to how much I've been able to research the views of people in this community and I certainly hope they are not as I characterized them, though as I will point out below many elements of @slatestarcodex's response confirm my concerns.

2. Given the last point, I fully acknowledge the danger of throwing stones lest I shatter my own glass house. However, leaving aside any blame, I think to make sense of my piece and @slatestarcodex's response requires a bit of context that clearly he lacked. First, outside

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Bezos' Razors:

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• If unsure who to work with, pick the person that has the best chances of breaking you out of a 3rd world prison.

Skinner's Law:

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2. Make the pleasure of doing it greater than the pleasure of not doing it.

Luck Razor:

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Bragging Razor:

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