Hi,

I have developed application for Energy Micro microcontroller (EFM32LG940F256).
I am using j-link base and Emacs witch GCC.
I connect GDB server with j-link and download code without any problem.
After some time I can see in Emcas message:

"Program received signal SIGTRAP, Trace/breakpoint trap
0x00000000 in _isr_vector"
On command line I can see output:

"ERROR: Communication timed out: Requested 4 bytes, received 0 bytes !
ERROR: Can not read register 15 (R15) while CPU is running
...Target halted (PC = 0x00000000)
Reading all registers
ERROR: Can not read register 0 (R0) while CPU is running
ERROR: Can not read register 1 (R1) while CPU is running
ERROR: Can not read register 2 (R2) while CPU is running
ERROR: Can not read register 3 (R3) while CPU is running
ERROR: Can not read register 4 (R4) while CPU is running
ERROR: Can not read register 5 (R5) while CPU is running
ERROR: Can not read register 6 (R6) while CPU is running
ERROR: Can not read register 7 (R7) while CPU is running
ERROR: Can not read register 8 (R8) while CPU is running
ERROR: Can not read register 9 (R9) while CPU is running
ERROR: Can not read register 10 (R10) while CPU is running
ERROR: Can not read register 11 (R11) while CPU is running
ERROR: Can not read register 12 (R12) while CPU is running
ERROR: Can not read register 13 (R13) while CPU is running
ERROR: Can not read register 14 (R14) while CPU is running
ERROR: Can not read register 15 (R15) while CPU is running
ERROR: Can not read register 16 (XPSR) while CPU is running
ERROR: Can not read register 17 (MSP) while CPU is running
ERROR: Can not read register 18 (PSP) while CPU is running
ERROR: Can not read register 24 (PRIMASK) while CPU is running
ERROR: Can not read register 25 (BASEPRI) while CPU is running
ERROR: Can not read register 26 (FAULTMASK) while CPU is running
ERROR: Can not read register 27 (CONTROL) while CPU is running
Read 4 bytes @ address 0x00000000 (Data = 0x20008000)"

I am using UART as output to write me messages, and from this I know that microcontroller continue to work without any problem.
I saw similar issue in this thread: STM32F427II debug issues
But comparing to this issue, my application is not using or programming pins for debug (PF0, PF1 and PF2)!
Can something else cause this problem ?(

Best regards