For a project I need to change the PWM duty cycle after a PWM period is over. One way to do this is to have an interrupt at the end of the PWM period, and then set the new PWM duty (compare) register value in the interrupt. That works fine for ‘slow’ PWM frequencies, but if the PWM frequency is high, the CPU load is massively increasing. A better way is to use DMA (Direct Memory Access).
FRDM-KL25Z with DMA PWM and Logic Analyzer
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
The standard Eclipse registers view only shows the core registers:
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
If you want the same, then this article is for you. It works both for stock Eclipse and Freescale Kinetis Design Studion (KDS) 🙂
For the next semester I will do things differently in my advanced embedded systems programming course (INTRO) at the University of Lucerne: Instead of using the Freescale provided CodeWarrior, we will use a DIY tool chain for ARM with Eclipse Kepler.
Eclipse Kepler Ready for Classroom Usage
That way we we can offer students an open and convenient tool chain for their lab work, course assignments and own projects both at work and at home. So this post is about spending about 30 minutes to build your own tool chain which then can passed to students and coworkers so they have a complete toolchain installed in a few minutes.
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
With the Joystick shield I have a convenient way to drive and control a Zumo Robot without a wired connection:
Joystick Shield with Robot
While things started promising, there was a power supply problem at the end to be solved…
I’m using both the Freescale MC1320x and Nordic Semiconductor nRF24L01+ 2.4GHz in many projects. To make it even easier to use these transceivers in the RNet stack, I have updated it with several new functions.
MC13202 and nRF24L01+
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
There must be an easier way for this? Yes, indeed, there is 🙂
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
The existing OpenSDAv1 (see “OpenSDA on the Freedom KL25Z Board“) bootloader is using the industry standard Motorola S-Record (S19) Files. However, new FRDM-K64F board (see “FTF: FRDM-K64F, Kinetis Design Studio and Kinetis SDK“) has OpenSDAv2 on it, which is an mbed bootloader. So how to create files with an IDE other than mbed for that bootloader which is present on the FRDM-K64F board by default? Well, creating binary files is one thing, but to have it working with the mbed bootloader is another challenge :-(.
FRDM-K64F with mbed MSD bootloader
