NRF51-DK Problem debugging mbed-os-example-blinky

Hi All,

I am new to MBED though I have used CMSIS-RTOS-RTX on a project back in the day when MBED was just getting started. I am using Mbed Studio v 1.0 downloaded in the last few days.

I have a new NRF51-DK board that I have updated the DAPLink firmware to version 0253 using the process described here, without apparent issue.

The MBED OS 5 version of the mbed-os-example-blinky program builds for without issue and I can download it to the target cpu on the NRF51-DK using the button (having the play icon) in Mbed Studio. This works fine and I can change the LED flash rate by setting BLINKING_RATE_MS to different values in main.cpp and seeing the results.

My problem arises when I try to debug the program (still in , obviously). The program builds and compiles OK and attaches to the debugger but I get the following error


05028:INFO:gdbserver:RTX5 loaded successfully
Attached to debugger on port 50000
0005170:WARNING:flash_builder:Chip erase used when flash address 0x1b000 is not the same as flash start 0x0
0007739:INFO:loader:Erased chip, programmed 67584 bytes (66 pages), skipped 0 bytes (0 pages) at 25.17 kB/s
Image loaded: c:\Users\Mike-remote\Mbed Programs\mbed-os-example-blinky-5-v2\BUILD\NRF51_DK\GCC_ARM\mbed-os-example-blinky-5-v2.elf
Note: automatically using hardware breakpoints for read-only addresses.
[New Thread 2]
[New Thread 536887008]
[New Thread 536886672]
[New Thread 536886940]
Thread
2 “Handler mode” received signal SIGSEGV, Segmentation fault.
[Switching to Thread 2]
0xfffffffe in ?? ()

Can anyone give me any ideas what is going wrong here and what I need to do to fix the problem ? The exact same .hex output file runs OK when I download it to the target by copying to the DAPLINK disk in Windows.

Thanks,

Just to say that in the above

“builds for” should read “builds for Build profile\Debug”

and

“(still in , obviously)” should read “(still in Build profile\Debug, obviously)”

Hi Mike,

Thank you for reporting this issue. Mbed Studio is using pyOCD to flash and debug program on the board. I believe that it may have an issue with debugging this particular board. We will investigate it further.

Thanks,
Arek - Mbed Studio team