As I mentioned last time, one of the features I like packaged with the FRDM-KL25Z release is the OpenSDA serial debugger from Pemicro (www.pemicro.com/opensda). The application creates a virtual USB drive on your PC where you can drag and drop a .bin (or. srec) file into the board bootlloader. The SDA takes it from there, loading and starting your program. Since the FRDM board’s power is supplied through the USB port, if something goes wrong, just disconnect then reconnect the SDA USB cable and the board returns to the default condition. This is because your .bin file is not permanently stored on the USB virtual drive. Not a good thing for long term testing, but great for initially checking your code.
For good reasons, you cannot update your program by just dropping a new .bin file into the directory. You must first clear the board by disconnecting/reconnecting the USB, then drop your file in.
All of the examples found on the Freescale’s website are under 90KB, so they don’t stretch the capabilities of the board or SDA application. The size of the virtual drive is 128K, the same as the flash memory on the FRDM-KL25Z. Whether the SDA software sets this based on the MCU available memory, am not sure.
Another feature is a USB serial console port for the debugger that allows the developer to communicate to the board through a terminal emulator (i.e. TeraTerm Pro, etc.). This is demonstrated using the low power demo program detailed in the quick start guide. When using Windows there is no clean way to break the console connection and I found the terminal emulator would often fail to close the port correctly when I disconnected the USB cable. Sometime you just have to wait.
Until next time… Gordon
