Slow 32 kHz Oscillator Startup

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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Preventing Reverse Engineering: Enabling Flash Security

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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Semihosting with Kinetis Design Studio

Semihosting is a technique to do printf() debugging through an active debug connection. So instead using a physical connection like RS-232 or USB CDC, the connection to the host machine is through the debugger. This post is about enabling and using semihosting with gcc and newlib/newlib-nano in Freescale Eclipse based Kinetis Design Studio (KDS) using the GNU ARM Eclipse plugins.

Semihosting Console View with output

Semihosting Console View with output

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How to Add Register Details View in Eclipse

The standard Eclipse registers view only shows the core registers:

Standard Registers View in Eclipse

Standard Registers View in Eclipse

I think it would be great to have a view to see all the device peripheral registers too?

Embedded System Registers View

Embedded System Registers View

If you want the same, then this article is for you. It works both for stock Eclipse and Freescale Kinetis Design Studion (KDS) 🙂

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Tutorial: Data Logger with the FRDM-K64F Board

The Freescale FRDM-K64F is a great board for data logger applications: it has a powerful ARM Cortex M4F with 120 MHz, 1 MB Flash and 256 KByte RAM. Best of all: it already has a micro SD card socket on the board :-).

Data Logger with FRDM-K64F

Data Logger with FRDM-K64F

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C/C++ Watchpoints with Eclipse Kepler

In “Watchpoints: Data Breakpoints” I used the Eclipse based CodeWarrior to set breakpoints so the debugger stops when my application is writing or reading a certain memory location. That CodeWarrior is based on an earlier Eclipse version, and things are different in Eclipse Kepler and not so easy to find. So here is how I can use watchpoints in Eclipse Kepler:

Watchpoints in Breakpoint View

Watchpoints in Breakpoint View

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Joystick Shield with nRF24L01 driving a Zumo Robot

With the Joystick shield I have a convenient way to drive and control a Zumo Robot without a wired connection:

Joystick Shield with Robot

Joystick Shield with Robot

While things started promising, there was a power supply problem at the end to be solved…

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GNU ARM Eclipse & Segger J-Link Device Name Settings

Thanks to the GNU ARM Eclipse plugins from Liviu it is easy to build and debug projects for all the different ARM cores. But I need to specify the device name in the debug configuration:

Device Name for Segger GDB Configuration

Device Name for Segger GDB Configuration

There must be an easier way for this? Yes, indeed, there is 🙂

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Segger J-Link Firmware for OpenSDAv2

Segger just has released their OpenSDAv2 firmware. The OpenSDAv2 firmware is different from the OpenSDAv1 as it is using a different memory map and bootloader. The OpenSDAv2 e.g. is present on the new FRDM-K64F board. The availability of the Segger firmware is definitely good news for any owner of the FRDM-K64F board: so far only the CMSIS-DAP firmware was available (on top of the mbed bootloader). With this, it was not possible to use the board with CodeWarrior, except with using an external P&E Multilink or Segger J-Link. With that new Segger J-Link OpenSDAv2 firmware, I can now use the FRDM-K64F with any IDE which supports the Segger J-Link :-).

FRDM-K64F with Segger OpenSDAv2 Firmware

FRDM-K64F with Segger OpenSDAv2 Firmware

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Using the FRDM-K64F with CodeWarrior

The new flagship of FRDM boards is the FRDM-K64F board. After FTF I have explored different ways debugging the board, and received many comments and questions about it (thanks!). Freescale announced the supports with the new Eclipse based Kinetis Design Studio (KDS). But until KDS is out, how can I use the FRDM-K64F board with CodeWarrior?

Debugging FRDM-K64F Board with CodeWarrior for MCU v10.6

Debugging FRDM-K64F Board with CodeWarrior for MCU v10.6

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