Cortex-M3 reset strategie 0 did`nt work! J-Link v5.0

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  • Cortex-M3 reset strategie 0 did`nt work! J-Link v5.0

    Hello!

    I`am using J-link v5.0 emulator and JFlashARM v4.00a software with STM32 Cortex-M3 microcontroller.
    And I have noticed recently, that there is absolutely no activity on the JTAG RESET pin (target CPU reset signal) while connection is in progress!
    Reset options is on the picture:

    Emulator connects to the core without lowering RESET level.
    This is why the core peripherals stays in it`s firmware configured state, and this is the root of the problems I have reported earlier!

    Solution is to set value0 in the reset type options to 2.

    But why the default type 0 did`nt work properly?

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

  • Hello sonycman,

    reset strategy 0 for Cortex-M3 behave as follows:
    Try to reset the core via reset strategy 1 (only the core is reset, peripherals are untouched). This is done because this strategy works
    for nearly all Cortex-M3 devices (even if the reset pin of the target CPU is not connected to the JTAG reste pin).
    If reset strategy 1 fails, try reset the core using the reset pin (reset strategy 2).

    In your case, the first try was succesful (strategy 1, core reset only), so the reset pin was not toggled.
    The explanation in the manual (UM08001) was wrong. We will correct this.

    Best regards,
    Alex
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  • SEGGER - Alex wrote:

    Hello sonycman,

    reset strategy 0 for Cortex-M3 behave as follows:
    Try to reset the core via reset strategy 1 (only the core is reset, peripherals are untouched). This is done because this strategy works
    for nearly all Cortex-M3 devices (even if the reset pin of the target CPU is not connected to the JTAG reste pin).
    If reset strategy 1 fails, try reset the core using the reset pin (reset strategy 2).

    In your case, the first try was succesful (strategy 1, core reset only), so the reset pin was not toggled.
    The explanation in the manual (UM08001) was wrong. We will correct this.

    Best regards,
    Alex
    Thank you, Alex.
    I will know it now!

    Regards.