No Cortex-M SW device found. Help please!!!

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  • No Cortex-M SW device found. Help please!!!

    Hello everyone,

    I'm getting this error "No Cortex-M SW device found" when trying to load code to a nrf51822 using Keil 5.14

    This is a screenshot of the J-Link Commander, which may help you to guess the problem.


    [img]http://i59.tinypic.com/10z8sd3.png[/img]


    I have made a little research:

    I have 2 J-link EDU, one new (bought last week and received today) and one old from my university.

    The old works perfectly with Keil but the new one doesn't.

    This is from the old one:

    [img]http://i58.tinypic.com/14avn92.png[/img]



    and this from the new one:

    [img]http://i59.tinypic.com/25ezk9u.png[/img]


    Why the SW Device doesn't appear using my new J-link ???

    Help please!!!

    Any idea ?

    Thanks in advance

    The post was edited 3 times, last by cybero ().

  • Hi,

    The Problem is the speed selection you have in uVision.

    For SWD, the V8 J-Link EDU supported up to 4 MHz.
    The new V9 J-Link EDU supports up to 12 MHz.
    You have selected 20 MHz.
    If a higher speed than supported, is selected, the speed is internally scaled down to the max. supported one.

    Unfortunately, the nRF51 devices do not seem to work with SWD speeds > 5 MHz. (We have tested other targets with 50 MHz SWD speed, but the max. usable speed heavily depends on the target device)

    Solution: Select 4 MHz in uVision. This setting will work for both.


    Best regards
    Alex
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/

    Or you can contact us via e-mail.
  • SEGGER - Alex wrote:

    Hi,

    The Problem is the speed selection you have in uVision.

    For SWD, the V8 J-Link EDU supported up to 4 MHz.
    The new V9 J-Link EDU supports up to 12 MHz.
    You have selected 20 MHz.
    If a higher speed than supported, is selected, the speed is internally scaled down to the max. supported one.

    Unfortunately, the nRF51 devices do not seem to work with SWD speeds > 5 MHz. (We have tested other targets with 50 MHz SWD speed, but the max. usable speed heavily depends on the target device)

    Solution: Select 4 MHz in uVision. This setting will work for both.


    Best regards
    Alex


    Hello Alex,

    Yes, you're right.

    I clicked on Auto Clk and the Clk frequency changed to 1 MHz and the SW Device appeared and worked fine.

    Where can I download the J-Link EDU specifications manual ? because just found this and I didn't find that issue with the clk frequency in anywhere.

    Thank you very much.

    Regards.
  • Hi,

    The J-Link EDU specification is the same as for the J-Link BASE / PLUS, when it comes to hardware: chapter 1.3.2 J-Link
    We are already reworking the model comparison, to make certain things clearer.


    Best regards
    Alex
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/

    Or you can contact us via e-mail.
  • SEGGER - Alex wrote:

    Hi,

    The J-Link EDU specification is the same as for the J-Link BASE / PLUS, when it comes to hardware: chapter 1.3.2 J-Link
    We are already reworking the model comparison, to make certain things clearer.


    Best regards
    Alex
    BTW, do you know if I can save this configuration in Keil ? because everytime I launch µVision the Clk frequency is set to 20 MHz and I have set it again to 1 MHz besides of changing again the ram's algorithm size.