Slow 32 kHz Oscillator Startup

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In an IoT (Internet of Things, see “IoT: FreeRTOS Down to the Micro Amps“) project I’m using the Freescale KL15Z microcontroller. The nodes are moving around, and the board is using a special inductive charging ‘on the fly’ when nearby the charging station. The energy is stored in capacitors, so no batteries are needed. That worked very well, but some system failed: they need to quickly check sensor signals after power-up. Tracking down the problem, it was obvious that most of the systems failed because it took them too long to boot from the power-on reset. So I instrumented the application to toggle an LED so I can monitor what happens: It was over 400 ms after power-on! Yikes!

413 ms for startup

413 ms for startup

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Finding Settings in Processor Expert Components

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Processor Expert components are making things very easy to configure: go a component, use the component inspector and change a setting. However, with the devices getting more and more complex, the list of settings or properties get longer and longer. To the point that it is hard to find a setting.

For example, where are the settings for the PLL in the CPU component?

Component with Settings

Component with Settings

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FILLing unused Memory with the GNU Linker

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In many of my applications I use a CRC/checksum to verify that the code/flash on the target is not modified. For this, not only the code/data in flash counts, but as well all the unused gaps in the memory map. Instead to leave it up to the flasher/debugger (which usually erases it to 0xFF), I want to fill it with my pattern. The GNU linker is using the pattern 0x00 for unused bytes inside sections. So this post is about to use the GNU linker to ‘fill’ the uninitalized FLASH memory with a pattern.

FLASH with DeadBeef Pattern

FLASH with DeadBeef Pattern

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Preventing Reverse Engineering: Enabling Flash Security

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Now I have invested a lot of time into my application, ready to be flashed on the devices and shipped. But wait: I don’t want that someone can read out the code from my device and have it reverse engineered. For this, I can ‘secure’ the device.

Flash Security Settings

Flash Security Settings

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Tutorial: DIY Kinetis SDK Project with Eclipse – Board Configuration

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In “Tutorial: DIY Kinetis SDK Project with Eclipse – Startup” I showed how to create a Kinetis SDK project from scratch. In this post it is about adding the board initialization files. With the board initialization the peripheral clocks and pin muxing is configured.

MK64FN1M0VLL12 on FRDM-K64F

MK64FN1M0VLL12 on FRDM-K64F

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Formula Student Electric “grimsel” Testing in Alpnach

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Here is another featured student project of this semester: Formula Student Electric (FSE). After the outstanding racing season with “Julier” in 2013, the students have designed and built a new and improved Formula Student Electric car “grimsel”, named after the Grimsel Mountain Pass.

Team Video:

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Programmable Ultrasonic Sensor Shield for FRDM Board

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“Note to myself: post articles about what students have done this semester…”

Students have turned in their semester project work. I have set for myself a goal to briefly describe to the ‘outside’ world what they did, as an inspirational source :-). So here is a first article about the project completed by Christoph Bühlmann who developed a shield for the FRDM-KL25Z board: a programmable ultrasonic shield:

Ultrasonic Shield with FRDM-KL25Z

Ultrasonic Shield with Freescale FRDM-KL25Z (Source: Christoph Bühlmann)

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Switching between ‘tabs’ and ‘no-tabs’ UI in Processor Expert

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Newer releases of Processor Expert (e.g. in Kinetis Design Studio (KDS)) come with a ‘graphical’ (or ‘tabbed’) view of the Component Inspector. The UI elements are different and ‘tabs’ are using:

Component Inspector in Tabbed View

Component Inspector in Tabbed View

I like much more the earlier ‘no-tabs’ view. Luckily, there is a setting to switch the view back.

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