In this tutorial I explored how to use printf(), and this tutorial is so generic that it works for any processor/microcontroller. That flexibility is because I’m using Processor Expert. In case Processor Expert shall not be used, then some tweaks are needed. Here I show what is needed to have printf() working with the FRDM-KL25Z board. I use the UART0 connected to OpenSDA USB CDC for this.
Freescale/Farnell/Element14 announced last week a new Freedom Board: the FRDM-K20D50M :-). As you can expect, I was not able to resist, and ordered one from my local Farnell store right away. So I did my first steps with it on this sunny and wonderful weekend (yes! we skipped Spring Time and entered Summer Time right away!).
I do not need to compare the board with the previous Freedom boards, as I have found an article here. I a nutshell: I get pretty much the same as with the FRDM-KL25Z, but instead of an ARM Cortex-M0+, it has an ARM Cortex-M4!
The new FRDM-K20D50M Board
In “Code Size Information with gcc for ARM/Kinetis” I use an option in the ARM gcc tool chain for Eclipse to show me the code size:
text data bss dec hex filename 0x1408 0x18 0x81c 7228 1c3c size.elf
I have been asked by a reader of this blog what these item numbers really mean. Especially: what the heck is ‘bss’???? 🙂
Eclipse has a nice feature to ‘shut up’ dialogs: In many dialogs I can select an option so that dialog does not show up again:
‘Dont’ show Again’ in Dialog
But what if I change my mind later on and what to have this dialog to show up again?
In “Tutorial: Accelerating the KL25Z Freedom Board” I used the MMA8451Q accelerometer on the FRDM-KL25Z board in a very primitive way: I’m reading directly some low-level registers from the device through an I2C low-level component. No calibrating, no special device feature setting, only raw values. Since then, things have been evolved: In “Tutorial: Creating a Processor Expert Component for an Accelerometer” I started to create a driver for this accelerometer, and since then a lot more functionality has been added.
Traced Accelerometer Values to the Shell
It happens to me many times: I’m stepping with the debugger through my code, and ups! I made one step too far!
Debugging, and made one step over too far
What now? Restart the whole debugging session?
Actually, there is a way to go ‘backwards’ 🙂
Continue reading
“As an engineer, you should ask for the best tools available. Spending money for better tools can make the difference between finding a problem quickly, or wasting days or weeks, and ultimately failing a project.” (unknown)
I had to learn it the hard way: some ‘hard-to-find-problems’ sometimes only can be found with some amount of luck, or with using a good trace solution. CodeWarrior already supports trace, such as using the MTB on the Cortex-M0+. But with this I’m limited to the on-chip trace buffer or on-chip RAM, which is better than nothing. But to solve the real hard problems, a bit of more power and memory is needed. And here where the P&E Tracelink comes into play: with 128 MByte trace buffer it would allow me to record a lot more trace data :-).
I’m using Version Control Systems like Git and SVN on a daily base. Because this gives me the opportunity to revert my changes and go back in time in my project. A VCS is incredible useful as well if I have deleted files or settings: restoring it is just a matter of a few mouse clicks.
But even without using a VCS, Eclipse has a built-in simple version control system: the Local History.
Eclipse History View
I’m recently dealing again with S19 (S-Record) files. I can easily generate S19 files from my ARM .elf files, but what I need is a simple decoder of the file format.
The good thing is: such a decoder is provided with CodeWarrior for MCU10.x 🙂
That capability is built into the Decoder.exe which is delivered with the Freescale S08 (or S12) tool chain, and is located inside the MCU\prog folder:
Decoder.exe inside MCU prog Folder
If you are a frequent reader of this blog, then you know: I’m a big fan of Processor Expert components. While there are many Processor Expert components delivered with CodeWarrior, it lacks many components and device drivers beside of the normal on-chip peripherals. But value gets added to an embedded project with all the external devices, sensors and actuators. That’s why I have created many more components which are available on my GitHub site. Readers of this blog have asked several times to create a tutorial on how to create a Processor Expert component. So why not working on that on a long Easter weekend full of cold rain and snow?
So here we go: a tutorial how to create a Processor Expert component for the MMA8451Q accelerometer found on the FRDM-KL25Z board:
MMA8451Q Accelerometer on the FRDM-KL25Z Board
MCU on Eclipse 