Posts

  • Intel Edison: i2c-6 with vanilla Linux

    Thanks to the amazing work of Andy Shevchenko, it’s possible to run recent vanilla Linux kernels on Intel’s discontinued Edison module. There is a nice writeup about this available on the web. One of the drawbacks of this approach, however, is that one of the two user-accessible I2C bus controllers is not available: i2c-6. This is due to the fact, that initially it’s configured to be used by the SCU and there is no way to change this. Read more...

  • I²C level shifting gone wrong

    In a recent project I had to connect a 3.3V I²C bus segment to a 1.8V I²C bus. Therefore, I decided to use a PCA9306 Dual Bidirectional I²C Bus and SMBus Voltage-Level Translator as it is a device specifically designed for the job and PCB space was valuable in this particular project. Strangely the I²C communication only worked intermittently. So I got out my oscilloscope and probed the SDA line on the 1.8V side. I could see strange dips during the high phases. Read more...

  • Denon iPod dock protocol

    I have recently gotten myself an ASD-11R iPod dock for my Denon DRA-700AE receiver in order to inspect the protocol that is being used for the communication between the two devices. My original intention was to display arbitrary information on the receiver display. Also, controlling an external device using the receiver controls or the remote control would have been nice. To tell you right away: I achieved neither. However, I learned something about the communication protocol along the way. Read more...

  • Debugging an OpenWrt/LEDE kernel using KGDB over serial

    When trying to get sound output up and running on my LinkIt Smart MT7688 I needed to debug the Linux Kernel. I am using the master branch of the OpenWrt/LEDE distribution and therefore wanted to configure the sound card using the simple-card device tree binding. Read more...

  • Installing Arch Linux with Kodi on a Wandboard Quad

    I have been looking into several options to run Kodi on a Wandboard Quad for some time now. I now have Arch Linux with Kodi running on it quite reliably now. I am writing down the steps here hoping that it helps others to achieve the same thing. This is also a memo for myself ;-) Read more...

  • Kryptonite U-lock bracket

    I recently bought a Kryptonite Evolution series 4 Standard U-lock for my bicycle. While I have been quite happy with the lock itself, I had issues with the bracket. The supplied bracket mounts on the bicycle tube by a strap that gets tightened with a bolt. That is generally a good idea because this type of bracket fits several different tube diameters. However, over the course of a few days the bracket would always come loose as the the strap slipped. At least that is what happened on my bicycle with its 28.6 mm tube and the lock being mounted vertically. Read more...

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