Cliffleblog!

I love the ARM Cortex-M series of microcontrollers. The sheer computational power they pack into a teensy, low-power package is almost embarrassing.

But, many Cortex-M parts are small — 4x4 millimeters small — and don’t have the pins left over for JTAG. For these parts, ARM introduced a new debug interface, called SWD.

Unfortunately, SWD isn’t well-supported by open-source tools. Support is in progress in most of them — including my personal favorite, OpenOCD — but I’ve had bad luck so far.

Anton Staaf was having the same issue, and decided to do something about it. He tricked the cheap, commonly-available FTDI FT232H chip into speaking the line-level SWD protocol. We’ve teamed up and, a week or so later, have something to show for it.

Presenting: swddude, the dead-simple programmer for SWD microcontrollers. (By “dead-simple” I mean “rather braindead” but it works!) Currently it can flash code onto the LPC111x, LPC11Cxx, and LPC13xx series. Support for more chips is in progress.

I’ve posted a mirror of the code on GitHub for your cloning pleasure. Happy hacking!

This paper, presented at PLDI ‘11, describes a key innovation behind Native Client, which is (as far as I’m aware) an industry first: the ability to verify the safety of a code-generating program, like a JIT or language runtime, and that of its output, on the fly. We can even support self-modifying code, with very little runtime overhead for verification. I firmly believe that active runtimes involving some degree of JIT code generation are the future, and this paper shows that we don’t have to sacrifice security or reliability to support them.

I designed the mechanisms behind this technology with Bennet Yee and David Sehr, for x86, x86-64, and ARM processors. The rest of the authors did the hard part: implementing it in a portable way and shipping it to the masses. If you’re using Chrome, you’re already using this technology.

We received an internal Google award for this paper.

As long-time readers know, I have an original MakerBot Cupcake. I’ve been frustrated with the upgrade path using official MakerBot Industries parts (which can be best summarized as “don’t upgrade”).

Then I saw Rob Giseburt’s 3G 5D Shield. It’s a clever upgrade board that breaks out some previously unused (on my bot) signals to drive an additional stepper. Inspired, I built my own version — much smaller, so that it doesn’t obstruct the reset button or JTAG port.

I give you: the 3G 5D Mini. It works great, and it’s completely compatible with Rob’s firmware (available through ReplicatorG). I’m getting the best print quality I’ve ever had, all thanks to a couple dollars’ worth of connectors.

I wanted a small toolchest to organize hand tools and soldering supplies in my office. Because I don’t like having to design anything more than once, I wrote a parametric chest-of-drawers generator in OpenSCAD. It’s adaptable to any material, any size, and any number of drawers. Go crazy!

I designed this endtable to fit between two chairs in our living room. We hadn’t been able to find a table in the right size for this odd spot, so I made this parametric — it can scale to any (reasonable) size and height. You can make it out of a single 2-by-4-foot sheet of plywood (or acrylic, or cardboard) with a laser cutter and little else.