Q&A

Everything you always wanted to know about Eclipse, Embedded Systems Programming, Software and Tools, or any topics of this blog, but where afraid to ask, then this page is for you.

Post a comment, and you might get an answer, either from myself or from the readers of this blog. Otherwise: the answer is always ‘42‘ 😉

For feature requests or bug reports on the McuOnEclipse project end Processor Expert components, you should use the GitHub issue tracking system:

McuOnEclipse Processor Expert components: https://github.com/ErichStyger/McuOnEclipse_PEx/issues
McuOneEclipse example projects: https://github.com/ErichStyger/mcuoneclipse/issues

869 thoughts on “Q&A”

Etienne on December 5, 2017 at 19:30 said:

Hi Erich! great work on his blog ! I’ll use some of your code inside my project ! Quick question about the freeRTOS PE component. I seem to get lost with the priority scheme of freeRTOS, interrupt and your implementation of the freeRTOS component.

I want to be sure of one thing : IDLE task is assigned priotity 0, I guess it’S the lowest priority, the priority we give in FRTOS1_xTaskCreate() (PE component) should be related to priority number of the free RTOS right ? not the priority of the interrupt.. which are inverted right ?

lets says i create 2 tasks with your component :
FRTOS1_xTaskCreate(tsk1, “Task1”, configMINIMAL_STACK_SIZE, &globalhost, 1, NULL);
FRTOS1_xTaskCreate(tsk2, “Task2”, configMINIMAL_STACK_SIZE, &globalhost, 2, NULL);

Task2 priority will be greater than Task1 ?

sincerely.

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- Erich Styger on December 5, 2017 at 20:15 said:
  
  Hi Etienne,
  the FreeRTOS component is using the normal FreeRTOS priority scheme (nothing different). If you are new to FreeRTOS and the ARM Cortex interrupts, then I recommend that you have a read at the multipart tutorial starting at https://mcuoneclipse.com/2016/08/14/arm-cortex-m-interrupts-and-freertos-part-1/.
  Keep in mind that FreeRTOS priorities start with zero as the lowest priority, while the ARM Cortex priorities have zero as the highest urgency level.
  So yes, 0 (or tskIDLE_PRIORITY) is the FreeRTOS priority for the IDLE task. The RTOS itself runs with its interrupts (SysTick, PendSV and PendSvReq) at the lowest interrupt priority (15 for 4 priority bits).
  And yes, for your example, the Task2 his higher urgency than Task1 and this one has higher urgency than the IDLE task.
  I hope this helps,
  Erich
  
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Soo-Chang, Lee on December 18, 2017 at 09:30 said:

Hello, Erich! I really ensjoy your blog!

I have a question about mbed, especially openSDA.
I build a board based on FRDM-KL43Z.
My trouble is my boards are doesn’t work in my PC. I think absent of bootloader is main problem. Can you teach me how install a new bootloader in a board? There is none-S/W in my board.

Here is my board symptom.
1. Power LED is working
2. MCU USB port ack as USB serial. But it cannot use as storage.
3. openSDA USB unack.

sincerely,
Soo-Chang

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- Erich Styger on December 18, 2017 at 12:02 said:
  
  Hi Soo-Chang,
  have a read at https://mcuoneclipse.com/2014/11/01/illustrated-step-by-step-instructions-updating-the-freescale-freedom-board-firmware/ how to update the bootloader/application.
  If you are using Windows 8 or 10, then have a read at https://mcuoneclipse.com/2016/08/01/bricking_and_recovering_opensda_boards_in_windows_8_and_10/ too.
  I hope this helps,
  Erich
  
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  - Soo-Chang, Lee on December 21, 2017 at 01:45 said:
    
    Hello again.
    
    I tried your guide. But it is different situation.
    My board flash is empty. So it doesen’t work as a writable device.
    
    Anyway I really appreciate of your advice again.
    
    sincerely Soo-Chang
    
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    - Erich Styger on December 21, 2017 at 08:39 said:
      
      Your openSDA/K20 is programmed, right? It does not matter if your KL43Z is empty or not: the K20 will programm it, no matter what.
      
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  - Soo-Chang, Lee on December 22, 2017 at 01:02 said:
    
    Actually, I’m not sure about that. I made my own PCB based on KL43Z. I used new K20. I think OpenSDA/K20 is not programmed as well. I don’t have any S/W in my board.
    I think the only way to install the bootloader is using jtag.
    
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    - Erich Styger on December 22, 2017 at 20:01 said:
      
      Ah, I see, I thought you are talking about the FRDM-KL43Z. So yes, if you have a board with a new K20DX128 chip, you need to program it first with the bootloader. E.g. in a way described in https://mcuoneclipse.com/2016/06/26/how-to-recover-the-opensda-v2-x-bootloader/
      
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- Soo-Chang, Lee on December 29, 2017 at 02:55 said:
  
  Thank you, Erich!
  I will follow your advice. Thankyou again!
  I will update my data later.
  
  P.S. Happy new year!
  
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NealXu on January 24, 2018 at 18:11 said:

Hi…in my case my boards are doesn’t work in my PC. I think absent of bootloader is main problem. Can you teach me how install a new bootloader in a board? There is none-S/W in my board.

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- Erich Styger on January 25, 2018 at 08:46 said:
  
  That depends on the board. Which board are you using? Otherwise have a read at https://mcuoneclipse.com/2014/11/01/illustrated-step-by-step-instructions-updating-the-freescale-freedom-board-firmware/
  I hope this helps,
  Erich
  
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brynn rogers on March 7, 2018 at 20:20 said:

Hi Erich,
I just noticed that NXP has a Low Voltage Hbridge PE component (LVHBridge) , and also a medium voltage Hbridge (MVHBridge) component that can be downloaded and work on processors like the K20’s with Processor Expert. Have you seen these before and do you have any experience with them?
I found it because I want to make a stepper motor driver (microstepping) using discrete components on the theory that it could be better/cheaper than using a microstepping chip- these components look like the easy way to do so.

Brynn

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- Erich Styger on March 7, 2018 at 21:09 said:
  
  I have no experience with these components.
  
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Eli Naiman on April 7, 2018 at 16:18 said:

Hi Erich,
I am working on a project where I send short text messages between a K64F and an android tablet. I want the K64F to be a host and the tablet to be a device. How do I do this. Do I need an OTG cable.

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- Erich Styger on April 8, 2018 at 17:39 said:
  
  Hi Eli,
  the means that the K64F needs to be in host mode. If you are using the FRDM-K64F board, then this is not supported out of the box. Basically you need to supply 5V from the board to the tablet. See https://mcuoneclipse.com/2012/10/15/usb-host-mode-hack-for-the-freedom-kl25z-board/ and https://mcuoneclipse.com/2013/03/02/usb-msd-host-for-the-freedom-board/. The bigger thing is that you need a USB CDC host implementation running on the K64F. I had this on my ‘wish list’ for a very long time, but never got to the point to have the USB stack working that way. You might need to check the latest NXP MCUXpresso SDK if it supports what you need?
  
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Eli Naiman on April 15, 2018 at 21:43 said:

Hi Erich
I am trying to modify your example using the Adafruit SPI friend. I want to use the Freedom K64F instead of the Tiny20.

For the Adafruit SPI you use 5 IO lines. I want to use the Adafruit UART friend, no interrupt and the CS tied to GND. This will use up only 2 IO lines.

Will this work?

Thanks
Eli

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- Erich Styger on April 16, 2018 at 08:16 said:
  
  Using the K64F instead the K20 should be pretty straight forward. But there is no CS line on the UART friend (https://www.adafruit.com/product/2479)?
  Keep in mind that for the UART friend you have to use UART hardware flow control, and not every UART peripheral might support that. From that perspective, the SPI BLE Friend is much easier to use imho.
  
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Mark on April 25, 2018 at 21:21 said:

Hi Erich,
Great website ! I found the site not too long ago ! You seem like a person who loves these works and want to teach others as well!
I have been struggling to learn embedded electronics but what I have discovered missing is a complete guideline from beginner to expert. If you could write an article on where to start and how to grow from there would benefit many beginners like me I believe.

Thanks
Mark

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- Erich Styger on April 26, 2018 at 05:54 said:
  
  Hi Mark,
  thank you for that feedback and suggestion. My suggestions would be to look first for some of the older articles (as they are more beginner like). And what would you define as tha ‘beginners knowledge’ to build upon?
  
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  - Mark on April 27, 2018 at 01:14 said:
    
    First, thanks for the quick response. I would say a beginners knowledge is basic knowledge of programming in C, some familiarity with electronic components and someone with enough knowledge to play around with arduino or similar platform. For example, right now I find programming in arduino or in mbed online compiler fairly easy as they hide many details. Also there are a lot of tutorial for them available online as well. But when I dive under the hood,I don’t know where to begin with.
    
    Mark
    
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    - Erich Styger on April 27, 2018 at 05:50 said:
      
      Hi Mark,
      maybe have a look at tutorials like these:
      https://mcuoneclipse.com/2016/03/13/tutorial-blinky-with-the-frdm-kl27z-and-kinetis-sdk-v2/
      https://mcuoneclipse.com/2016/05/20/tutorial-blinky-with-nxp-kinetis-sdk-v2-0-and-processor-expert/
      https://mcuoneclipse.com/2017/05/13/mcuxpresso-ide-blinky-the-nxp-lpc800-dip-board/
      Erich
      
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    - Mark on April 27, 2018 at 23:54 said:
      
      Perfect ! Thanks a lot for taking your time to find the links for me!
      
      Have a great day !
      Mark
      
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Jahedur Rahman on April 26, 2018 at 20:58 said:

Hi Erich,
So I was trying to do the DIY USB joystick but I keep getting this error: “Description Resource Path Location Type
Generator: FAILURE: at line 10: Property not found: “TxBuffer” (file: Drivers\Common\FSL_USB_HID_Joystick_DeviceSettings.Inc) FRDM-KL25Z_USB_HID_Joystick HIDJ1 Processor Expert Problem”
Can you help me please?

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- Erich Styger on April 27, 2018 at 05:52 said:
  
  Hi,
  I suggest that you post that question directly to the article you are using? Are you using my project from GitHub (which one)?
  But it seems to me that you did not assign a ring buffer to the USB component?
  
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  - Jahedur Rahman on April 27, 2018 at 14:02 said:
    
    I was trying to comment on that post but it says sorry can’t post :(. It’s the project from Github and the tutorial is on this site too. https://mcuoneclipse.com/2017/06/04/diy-usb-hid-joystick-device-and-game-controller/
    
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    - Jahedur Rahman on April 27, 2018 at 14:05 said:
      
      It let me comment on the tutorial now :).
      
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Eli Naiman on April 28, 2018 at 20:59 said:

Hi again
I have an android tablet talking to a K64F using the Adafruit LE uart. However it will not send more that 20 bytes at a time.Is there a way to increase this limit.
Thanks

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- Erich Styger on April 29, 2018 at 08:06 said:
  
  You have to implement message fragmentation (sending larger chunk of data with multiple messages). The BLE protocol is optimized for low power and small amount of data, you cannot send more than this 20 bytes in a a single message.
  
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Ejaz Q on May 2, 2018 at 20:20 said:

Hi Eric,
Great work. Really appreciate your insights. Had a question. Is it possible to shutdown a cortex m4? I understand the CPU can be configured to go in Stop Mode or Sleep Mode, but is it possible to to initiate a shutdown from software? I don’t think it is possible as I cannot find any register set that lets me perform such an action, but wanted to run it by you as well
Thanks again

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- Ejaz Q on May 2, 2018 at 20:24 said:
  
  apologies for misspelling your name. I meant to type Erich
  
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  - Erich Styger on May 2, 2018 at 20:34 said:
    
    No worries, both variants work very well 🙂
    
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- Erich Styger on May 2, 2018 at 20:25 said:
  
  You can reset any M3/M4/M7 using the approach described in https://mcuoneclipse.com/2015/07/01/how-to-reset-an-arm-cortex-m-with-software/. But this will be a reset/restart.
  If you want to do a ‘shutdown’ as on the PC then could either go into deep sleep mode or do a reset and right after that go into deep sleep.
  
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  - Ejaz Q on May 2, 2018 at 20:28 said:
    
    yep. that’s what I had in mind as well. Thanks soo much. Once again, a great website and great resources.
    
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Panagiotis on May 22, 2018 at 00:20 said:

Hello Erich,
First of all I would like to thank you for the awesome work and for the effort you have put into these tutorials. I have the following question. I ordered the product FRDM-K64F-AGM01, which consists of a shield and a development board. From the pictures at NXP site, I infered that the sensor shield board would be removable and that I could use the FRDM-K64F standalone. The problem is I can’t remove the shield (if I apply more pressure, I am scared that I will break the board). Do you know if it is supposed to not be removed?

Thanks in advance,
Panagiotis

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- Erich Styger on May 22, 2018 at 05:10 said:
  
  It should be removable. I don’t have that kit, but from the pictures it really should be removable. You should be able to tell this with having a close look at the headers: ther must be a black (high) black row of female headers on the FRDM-K64F board, with a row of male pin headers on the AGM01 board. Try to lift the board carefully on one end, then on the ohter, and so on.
  I hope this helps,
  Erich
  
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Rohit on July 23, 2018 at 11:46 said:

Hello Erich ,
I have to configure a common SPI bus to be used for two different SP clock frequency 2MHz and 8MHz on K10 series controller. I am using SPIMaster_LDD component in processor expert V10.4.0T.The method SetClockConfiguration() is appear as disabled . How can I enabled it and select the generate code option. Please explain .

Thanks and Regards,
Rohit K.

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- Erich Styger on July 23, 2018 at 20:41 said:
  
  Hi Rohit,
  You have to use the SelectConfiguration() (not SetClockConfiguration()) method. Have a read in https://mcuoneclipse.com/2014/05/26/tutorial-data-logger-with-the-frdm-k64f-board/ and search for SelectConfiguration. In the clock rate configuration of the component you have to use ‘list of values’.
  I hope this helps,
  Erich
  
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  - Rohit on July 25, 2018 at 12:10 said:
    
    Thank you Erich.
    
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  - Rohit on July 27, 2018 at 12:42 said:
    
    Hi Erich,
    
    In the clock rate configuration of the component i have used ‘list of values’.
    In value type , I am using mode 0 and mode 1.
    
    I am setting following the values : mode 0 = 0.125µsec and mode 1= 0.5µsec.
    
    When I reopen the clock rate configuration window , I observed that mode 1 value that I was set is not there. Mode 1 shows the same value as mode 0.
    Can you please let me know why this is happening?
    
    Thanks and Regards,
    Rohit K.
    
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    - Erich Styger on July 29, 2018 at 10:19 said:
      
      Hi Rohit,
      not sure what is causing this. I assume you have pressed the OK button? The other thing is: have you picked the values from the ‘Possible settings’ list (e.g. double-clicking on the value)? If the value you have entered is not part of that list, it will not be applied.
      I hope this helps,
      Erich
      
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Diogo Morais on August 1, 2018 at 20:38 said:

Hello, Erich,
im thinking about trying to do a firmware update over the air with delta file optimization. Do you something about that? An elipse configuration which does not change all the file over the smallest change in code, maybe?
Regards,
Morais D.

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- Erich Styger on August 1, 2018 at 22:35 said:
  
  Yes, I have done something like this where we are updating the firmware of a small satellite in space. But this was a customer paid project so it is not available to the public.
  
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  - Diogo Morais on August 1, 2018 at 23:30 said:
    
    Do you can provide some tips about this subject? Off course, that isn’t specific with this project and does not violate, in any way, your relation with the costumer.
    Regards,
    Morais D.
    
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    - Erich Styger on August 2, 2018 at 07:27 said:
      
      Here are a few ideas:
      – use dedicated linker sections to separate functions/files, e.g. https://mcuoneclipse.com/2014/10/06/putting-code-of-files-into-special-section-with-the-gnu-linker/
      – keep deltas between firmware versions small
      – create delta files for the firmware update, write your own tool to create the delta or use programs like Srecord (from SourceForge)
      – use a simple compression scheme, e.g. Run-Length-Encoding
      – pack everything into a communication protocol suitable for the above
      I hope this helps 🙂
      Erich
      
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    - Diogo Morais on August 2, 2018 at 13:58 said:
      
      That helps a lot, thank you one more time!
      Regards,
      Morais D.
      
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Radhika on January 8, 2019 at 10:31 said:

Hi Erich,

Happy New Year 2019.
I was looking for some examples for ARM Cortex-M33 with TrustZone and FPU. I couldn’t find any articles on Cortex-M33 here. It is a relatively new ARM core and firmware development on Cortex-M33 is still in nascent stages. Can you please consider writing about it in your next blog?

Thanks
Radhika.

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- Erich Styger on January 8, 2019 at 18:41 said:
  
  Hi Radhika,
  thanks, Happy New Year to you too!
  Yes, Cortex-M33 is on my radar, but because I have not ordered or used any of these in my projects, I have not written any articles about it. I’ll have to see if one of the university research projects starting next semester could benefit from a M33, and then certainly I will come up with an article about it.
  
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Andy on April 2, 2019 at 13:22 said:

Hi Erich,

Any idea why the MK20DX128xx5 is not supported in the MCUXpresso IDE? they only seem to have an SDK file for the parts ending in 10 (e.g. MK20DX128xx10).

Thanks

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- Erich Styger on April 2, 2019 at 14:14 said:
  
  No real idea. But I think it is maybe because this was one of the very first Kinetis devices, so it seems NXP has left it behind from the SDK point of view. The FRDM-K20 board for it is not available any more too.
  But we are using the MK20DX128x5 in many of our designs, and that’s why we continue to use Processor Expert because it is supported with it.
  
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