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Raspberry Rockets
One of the things I most enjoy about teaching embedded systems is that the students show up with a very diverse set of skills. Some are straight-up CS, meaning they can hack but probably are intimidated by a breadboard, logic analyzer, or UART. Others are EE, meaning that they can design a noise-free circuit or…
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How Did Software Get So Reliable Without Proof?
Tony Hoare’s 1996 paper How Did Software Get So Reliable Without Proof? addresses the apparent paradox where software more or less works without having been either proved correct or tested on more than an infinitesimal fraction of its execution paths. Early in the paper we read: Dire warnings have been issued of the dangers of…
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EMSOFT 2012
I just got back from Tampere, Finland where I was one of the program chairs for EMSOFT, an embedded software conference. If I haven’t blogged about this much, it’s because I’m sort of a reluctant and not especially talented organizer of events. Happily, EMSOFT is just one third of the larger Embedded Systems Week, so…
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ARM Math Quirks on Raspberry Pi
Embedded processors can be relied upon to be a little quirky. Lately I’ve been playing around with the Raspberry Pi’s BCM2835 processor, which is based on the ARM1176JZF-S core. The “J” stands for Jazelle, a module that permits this processor to execute Java bytecodes directly. As far as I know there’s no open source support…
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Thoughts on Embedded Development Boards
An embedded development board is an off-the-shelf part that includes a microcontroller and some peripherals, mounted on a PCB. It tries to not get in the way of whatever you want to do, but instead makes it easy to start writing software and attaching hardware. Some boards even include a bit of prototyping space. The…
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High-Resolution Timing on the Raspberry Pi
Just to be clear, this post is about measuring the times at which events happen. Making things happen at specific times is a completely separate (and much harder) problem. The clock_gettime() function (under Raspbian) gives results with only microsecond resolution and also requires almost a microsecond to execute. This isn’t very helpful when trying to…
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Android Projects Retrospective
The Android Projects class I ran this semester has finished up, with students demoing their projects last week. It was a lot of fun because: I find mobile stuff to be interesting the students were excited about mobile the students were good (and taught me a ton of stuff I didn’t know) the course had…
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Hello Android
Some semesters I teach courses that just need to be taught. On the other hand, this Fall I get to teach a class that should be purely fun — an Android projects course for upper-level undergrads. I already promised an “A” to anyone who (legitimately) makes at least $100 using an application developed for the…
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Why Verify Software?
People like me who work on software verification (I’m using the term broadly to encompass static analysis, model checking, and traditional formal verification, among others) like to give talks where we show pictures of exploding rockets, stalled vehicles, inoperable robots, and crashed medical devices. We imply that our work is helping, or at least could…
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Do Small-RAM Devices Have a Future?
Products built using microcontroller units (MCUs) often need to be small, cheap, and low-power. Since off-chip RAM eats dollars, power, and board space, most MCUs execute entirely out of on-chip RAM and flash, and in many cases don’t have an external memory bus at all. This piece is about small-RAM microcontrollers, by which I roughly…