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Hardfault without debugger - simple toggle IO program

Hi guys,

I'm trying to start with a simple IO toggle program on the nRF52 on a Thingy52 board. I have erased the micro so there is no soft device. I'm working in Eclipse Neon 3 using ARM Cross Compiler plugin.

#include "nrf.h"    
#include "nrf_delay.h"
#include "nrf_gpio.h"

int main(void)
{
	nrf_gpio_cfg_output(2);

	for(;;)
	{
		nrf_gpio_pin_toggle(2);
		nrf_delay_ms(50);
	}

	return 0;
}

I can compile and run it OK with my Segger JLink connected. However when I turn it off/on without the debugger running the micro hangs and does not toggle. Reconnecting the debugger shows it's in HardFault_Handler and it got there via the sequence: image description

Others have suggested to disable semi-hosting which I believe I have done.

My compilation flags (excluding #include search folders) looks like:

arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -mlittle-endian -mfloat-abi=hard -mfpu=fpv4-sp-d16 -munaligned-access -O0 -fmessage-length=0 -ffunction-sections -fdata-sections -fno-builtin -Wall -Wextra  -g -DNRF52832_XXAA -DNRF52_PAN_12 -DNRF52_PAN_15 -DNRF52_PAN_20 -DNRF52_PAN_31 -DNRF52_PAN_36 -DNRF52_PAN_51 -DNRF52_PAN_54 -DNRF52_PAN_55 -DNRF52_PAN_58 -DNRF52_PAN_64 -DNRF52_PAN_74 -std=gnu11 -Wa,-adhlns="src/src_nrf/nrf_drv_uart.o.lst" -fno-strict-aliasing -fshort-enums  -MMD -MP -MF"src/main.d" -MT"src/main.o" -c -o "src/main.o" "../src/main.c"

My linker script (mostly a copy of the generic one):

/* Linker script to configure memory regions. */

SEARCH_DIR(.)
GROUP(-lgcc -lc -lnosys)

MEMORY
{
   FLASH (rx) : ORIGIN = 0x0, LENGTH = 512K

   RAM (rwx)  : ORIGIN = 0x20000000, LENGTH = 64K
}

SECTIONS
{
  .fs_data :
  {
    PROVIDE(__start_fs_data = .);
    KEEP(*(.fs_data))
    PROVIDE(__stop_fs_data = .);
  } > RAM
} INSERT AFTER .data;

SECTIONS
{
  .pwr_mgmt_data :
  {
    PROVIDE(__start_pwr_mgmt_data = .);
    KEEP(*(SORT(.pwr_mgmt_data*)))
    PROVIDE(__stop_pwr_mgmt_data = .);
  } > FLASH
} INSERT AFTER .text

OUTPUT_FORMAT ("elf32-littlearm", "elf32-bigarm", "elf32-littlearm")

/* Linker script to place sections and symbol values. Should be used together
 * with other linker script that defines memory regions FLASH and RAM.
 * It references following symbols, which must be defined in code:
 *   Reset_Handler : Entry of reset handler
 *
 * It defines following symbols, which code can use without definition:
 *   __exidx_start
 *   __exidx_end
 *   __etext
 *   __data_start__
 *   __preinit_array_start
 *   __preinit_array_end
 *   __init_array_start
 *   __init_array_end
 *   __fini_array_start
 *   __fini_array_end
 *   __data_end__
 *   __bss_start__
 *   __bss_end__
 *   __end__
 *   end
 *   __HeapBase
 *   __HeapLimit
 *   __StackLimit
 *   __StackTop
 *   __stack
 */
ENTRY(Reset_Handler)

SECTIONS
{
    .text :
    {
        KEEP(*(.isr_vector))
        *(.text*)

        KEEP(*(.init))
        KEEP(*(.fini))

        /* .ctors */
        *crtbegin.o(.ctors)
        *crtbegin?.o(.ctors)
        *(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
        *(SORT(.ctors.*))
        *(.ctors)

        /* .dtors */
        *crtbegin.o(.dtors)
        *crtbegin?.o(.dtors)
        *(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
        *(SORT(.dtors.*))
        *(.dtors)

        *(.rodata*)

        KEEP(*(.eh_frame*))
    } > FLASH

    .ARM.extab :
    {
        *(.ARM.extab* .gnu.linkonce.armextab.*)
    } > FLASH

    __exidx_start = .;
    .ARM.exidx :
    {
        *(.ARM.exidx* .gnu.linkonce.armexidx.*)
    } > FLASH
    __exidx_end = .;

    __etext = .;

    .data : AT (__etext)
    {
        __data_start__ = .;
        *(vtable)
        *(.data*)

        . = ALIGN(4);
        /* preinit data */
        PROVIDE_HIDDEN (__preinit_array_start = .);
        KEEP(*(.preinit_array))
        PROVIDE_HIDDEN (__preinit_array_end = .);

        . = ALIGN(4);
        /* init data */
        PROVIDE_HIDDEN (__init_array_start = .);
        KEEP(*(SORT(.init_array.*)))
        KEEP(*(.init_array))
        PROVIDE_HIDDEN (__init_array_end = .);


        . = ALIGN(4);
        /* finit data */
        PROVIDE_HIDDEN (__fini_array_start = .);
        KEEP(*(SORT(.fini_array.*)))
        KEEP(*(.fini_array))
        PROVIDE_HIDDEN (__fini_array_end = .);

        KEEP(*(.jcr*))
        . = ALIGN(4);
        /* All data end */
        __data_end__ = .;

    } > RAM

    .bss :
    {
        . = ALIGN(4);
        __bss_start__ = .;
        *(.bss*)
        *(COMMON)
        . = ALIGN(4);
        __bss_end__ = .;
    } > RAM

    .heap (COPY):
    {
        __HeapBase = .;
        __end__ = .;
        PROVIDE(end = .);
        KEEP(*(.heap*))
        __HeapLimit = .;
    } > RAM

    /* .stack_dummy section doesn't contains any symbols. It is only
     * used for linker to calculate size of stack sections, and assign
     * values to stack symbols later */
    .stack_dummy (COPY):
    {
        KEEP(*(.stack*))
    } > RAM

    /* Set stack top to end of RAM, and stack limit move down by
     * size of stack_dummy section */
    __StackTop = ORIGIN(RAM) + LENGTH(RAM);
    __StackLimit = __StackTop - SIZEOF(.stack_dummy);
    PROVIDE(__stack = __StackTop);

    /* Check if data + heap + stack exceeds RAM limit */
    ASSERT(__StackLimit >= __HeapLimit, "region RAM overflowed with stack")
}

My linker call looks like:

arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -mlittle-endian -mfloat-abi=hard -mfpu=fpv4-sp-d16 -munaligned-access -O0 -fmessage-length=0 -ffunction-sections -fdata-sections -fno-builtin -Wall -Wextra  -g -T "D:\nRF_Workspace_Neon3\Blinky2point0/linker/blinky_gcc_nrf52.ld" -Xlinker --gc-sections -Wl,-Map,"Blinky2point0.map" -Wl,--start-group -lgcc -lc -lc -lm -Wl,--end-group -o "Blinky2point0.elf"  ./src/src_nrf/gcc_startup_nrf52.o ./src/src_nrf/nrf_assert.o ./src/src_nrf/nrf_drv_common.o ./src/src_nrf/system_nrf52.o  ./src/main.o

Stack region of memory: image description

Can anyone please point me in the right direction?

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