For more information, visit: http://opencoral.com/ocluna/start

You can also find his open source design on Github.

• an old Python application server (Cymbeline)
• an audio player library (PyAudioPlay)
• a project which combines the two (Shallot)
• and even a very minimal NTP replacement (SNTS)

Note that this software is from the 2004 vintage, which reflects a previous era (before Git, before the end of college, etc). It was languishing on the StackFoundry website prior to its overhaul; I also couldn’t simply throw it away.

Also loaded onto github are slightly newer projects, such as:

• the static site generator qsgen
• a movie file browser (quick movie)
• the ptee process/subshell tee augmentation
• and finally an X11 keyboard wedge program for barcode readers (softwedge).

Most of the previous pages at StackFoundry now redirect to the appropriate github page.

Enjoy!

However, there are very few players in the ultra-low power space. Ultra-low power is characterized by very low operational currents coupled with ultra low sleep currents, often with clocks running. Texas Instruments is the former champion here, with their MSP430 line. Its a clean 16-bit architecture (now bizarrely extended to 20-bit for more memory space – flash and RAM is all in one space as most modern processors), where the new parts have run currents of < 200 microamps (uA) per MHz, and sleep currents with 32kHz clocks running at 2.5uA. This is what you need to run for years on AA batteries.

What if you could exceed that, with an ARM Cortex-M3 core, with hardware divide and MAC, running at 32MHz, and a host of nice peripherals?

Then check out the EFM32 processors from Energy Micro. I know I am…

I just re-launched OpenCoral in an open Wiki format, giving a common resource for those projects still under development by other teams and groups. A section for links, other controllers, and technical/electronics resources is available.

Then get my Chrome DigiKey Enhancements extension now!

The current version:

1. Adjusts the height of the search selector boxes to a user configurable value
2. Auto-checks all “In Stock” checkboxes (when configured)

The extension has an options pages (under the Tools->Extension page, click “Options” under DigiKey Enhancements) which allows you to pick which modifications the extension performs.

Untested: International DigiKey pages, full ordering workflow.

More features coming soon!

The BSL disallows memory reads and writes until a “password” has been transmitted over the serial interface. The password is actually a copy of the interrupt vectors (32bytes) used by the micro-controller, which limits the entropy available by a significant margin: addresses are all even aligned, reset vector is generally start of flash, many interrupt vectors will be identical, general case has all interrupt vectors located in flash. The only defense against this low-entropy brute force attack is the rate limit of the BSL: some versions of the BSL prevent you from changing from 9600 baud until after the password has been verified. However, on devices with small amounts of flash (say, 8Kib), there are only about 61,000 passwords generally in use, which reduces the search time tremendously.

Some BSL versions are also susceptible to side channel attacks are discussed in this paper:
Practical Attacks against the MSP430 BSL

Texas Instruments has improved code security on the new F5xxx series devices in a drastic way: an invalid password will cause a complete device erase. Note that the flash memory also differs from the previous generation devices by being rated to erase and program as low as 1.8V (where the core voltage normally sits – the 5 series has an integrated LDO).

I can see two possible attack vectors – undervoltage to the entire processor (I have a ’5438A running as low as 1.5V, however the BSL is not yet tested down here), or “glitching” the processor (in this case, complete power down) if the start bit of the acknowledgement packet is not transmitted within an allowable window. The second scenario can be defended against in the BSL firmware (delay the acknowledge by a large value).

I have not tried either of these attacks on the 5xxx series yet (specifically, the 5438 and 5438A). Generally, there are easier ways to attack processors to capture embedded code, or simply replicate external functionality based on observed behavior (code security is not on most programmers’ minds). If small-memory variants of the 5xxx series become available (to allow the brute-force searching of the keyspace), the flash memory erase issue would have to be overcome.

In the mean time, you can use some chip disassembly techniques from Flylogic.

On another note, I will be announcing a security related, open source hardware project shortly. Its been keeping me distracted from EVE-Central (trade route tool version 2, specifically), Contribtastic, and working on the EVE-Metrics/EVE-Central unified uploader.

Here is the WikiReader, unpacked. I wasn’t expecting a nice box and manual (even the iPhone doesn’t come with that), but was very pleasantly surprised.

Apologizes for the very poor picture quality – these are simply iPhone snaps – I didn’t take the time to break out the 5D.

The two main complaints I have so far are the scrolling of text and the keyboard. The scrolling makes the text largely unreadable – there are some different display techniques here which could improve the display. The keyboard could also take a few cues from Apple, such as the magnified key presses, which would go a long way to improving usability. There are some other bugs in the contents (such as the lack of full UTF-8 support), but those are minor at this point.

Aside from those complaints, this device is actually quite slick. The performance is EXCELLENT. Random takes no more than a second to load the next article, search automatically filters based on your entry very quickly, and the history feature even remembers where you were in an article. The device is light and portable, and the whimsical asymmetric design is a nice touch and not over-done.

But enough with the quick mini review, what technical fun toys are there for you to play with?

Well, the WikiReader has a built in calculator – while powering up the device, hold the center (History) button.

There is also a factory test mode available – while powering up the device, hold either the Search or Random button:

As you likely (can’t) see in the image, the bulk of the functionality is a set of Forth applications, including the aforementioned calculator. They’re largely there for factory test, but at least one of them lets you draw pretty pictures.

Not drawn using the draw application, but another LCD test app – you don’t want to see my artwork

The WikiReader also contains a thermistor, which appears to be there for maintaining LCD contrast automatically:

Last but not least, there is a Console, which probably is exposed in the hidden programming/debug port available in the battery compartment (peel off the big white rectangular sticker – not the FCC/CE/Regulatory sticker).

Below is a video of my first attempt at using OpenCV. It applies several filters to isolate the keys on the racetrack approximately 2 frames ahead of the goal position. The primary heuristic right now is a threshold detect filter after all of the isolation steps. If you watch closely, you can see missed or over-pressed keys, especially when the whole racetrack lights up.

Note that the video output has an overlay color square which announces the software has detected a keypress. The actual gameplay is from another YouTube video – there is no closed loop control yet.

This will take some more tuning to iron out differences, possibly preserving some state from frame to frame. Right now color information is not used, but a separate classifier pipeline and some scoring mechanic might produce better results.

I will publish the git repository with the very-alpha implementation soon.

The Magnetovore is an AVR xMEGA based development board which features external SRAM or non-volatile Magneto-resistive RAM (MRAM). Click through one of the above links for more details.