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Segger Fixed Memory Allocation in Flash and SoftDevice compatibility.

Hi All,

New user here but couldn't find a concrete answer to the following question.

In PIC land I've usually allocated fixed memory using the _at_ or __attribute__ label but Segger doesn't support this. From googling I read to add a reference to the xml file, which I've done as shown below:

<!DOCTYPE Board_Memory_Definition_File>
<root name="nRF52810_xxAA">
  <MemorySegment access="ReadOnly" name="FLASH1" size="0x00030000" start="0x00000000" />
  <MemorySegment access="Read/Write" name="RAM1" size="0x00006000" start="0x20000000" />
  <MemorySegment access="Read/Write" name="CODE_RAM1" size="0x00006000" start="0x00800000" />

  <MemorySegment name="$(FLASH_NAME:FLASH)">
    <ProgramSection alignment="4" load="Yes" name=".settingsStore" start="0x00000000" />
  </MemorySegment>
</root>

You can see that the start is 0x0 which is probably a bad idea, likely the entry point of the application if it's like PIC's. A related question to ask at this point is where does a SoftDevice get placed in Flash?

Back to the main question, I then have the following to take up a 4kb page of flash (actual usage is 1kb so plenty for futureproofing).

static const union {
  struct settingsProto settings;
  uint8_t pad[FLASH_PAGE_SIZE_BYTES];
} store __attribute__((section(".settingsStore"))); // reserve flash page

Upon build I receive the error:

unplaced section: .settingsStore [config.o], size=4000, align=4



  • OK I've got that part working. Values used for the 810/s112v7.01 are:

    RAM_PH_START=0x20000000

    RAM_PH_SIZE=0x6000

    FLASH_PH_START=0x0

    FLASH_PH_SIZE=0x30000

    FLASH_START=0x19000

    RAM_START=0x20001000

    The debugger enters main() so that side of it is looking promising,

    Back to the settings section that I'd blocked off, I now get the error:

    Output/Debug/Exe/c1.elf section `.settingsStore' will not fit in region `UNPLACED_SECTIONS'
    region `UNPLACED_SECTIONS' overflowed by 4000 bytes

    I haven't changed the xml section or the const with __attribute which was posted earlier.

  • Ok, so your flash_placement.xml file still look like this?

    <!DOCTYPE Linker_Placement_File>
    <Root name="Flash Section Placement">
      <MemorySegment name="$(FLASH_NAME:FLASH);FLASH1">
        <ProgramSection alignment="0x100" load="Yes" name=".vectors" start="$(FLASH_START:)" />
        <ProgramSection alignment="4" load="Yes" name=".init" />
        <ProgramSection alignment="4" load="Yes" name=".init_rodata" />
        <ProgramSection alignment="4" load="Yes" name=".text" />
        <ProgramSection alignment="4" load="Yes" name=".dtors" />
        <ProgramSection alignment="4" load="Yes" name=".ctors" />
        <ProgramSection alignment="4" load="Yes" name=".rodata" />
        <ProgramSection alignment="4" load="Yes" name=".ARM.exidx" address_symbol="__exidx_start" end_symbol="__exidx_end" />
        <ProgramSection alignment="4" load="Yes" runin=".fast_run" name=".fast" />
        <ProgramSection alignment="4" load="Yes" runin=".data_run" name=".data" />
        <ProgramSection alignment="4" load="Yes" runin=".tdata_run" name=".tdata" />
      </MemorySegment>
      <MemorySegment name="$(RAM_NAME:RAM);SRAM;RAM1">
        <ProgramSection alignment="0x100" load="No" name=".vectors_ram" start="$(RAM_START:$(SRAM_START:))" />
        <ProgramSection alignment="4" load="No" name=".fast_run" />
        <ProgramSection alignment="4" load="No" name=".data_run" />
        <ProgramSection alignment="4" load="No" name=".bss" />
        <ProgramSection alignment="4" load="No" name=".tbss" />
        <ProgramSection alignment="4" load="No" name=".tdata_run" />
        <ProgramSection alignment="4" load="No" name=".non_init" />
        <ProgramSection alignment="4" size="__HEAPSIZE__" load="No" name=".heap" />
        <ProgramSection alignment="8" size="__STACKSIZE__" load="No" place_from_segment_end="Yes" name=".stack" />
        <ProgramSection alignment="8" size="__STACKSIZE_PROCESS__" load="No" name=".stack_process" />
      </MemorySegment>
      <MemorySegment name="$(FLASH2_NAME:FLASH2)">
        <ProgramSection alignment="4" load="Yes" name=".text2" />
        <ProgramSection alignment="4" load="Yes" name=".rodata2" />
        <ProgramSection alignment="4" load="Yes" runin=".data2_run" name=".data2" />
      </MemorySegment>
      <MemorySegment name="$(RAM2_NAME:RAM2)">
        <ProgramSection alignment="4" load="No" name=".data2_run" />
        <ProgramSection alignment="4" load="No" name=".bss2" />
      </MemorySegment>
      <MemorySegment name="settingsStore" start="0x0002F000" size="0x1000">
        <ProgramSection alignment="4" keep="Yes" load="No" name=".settingsStore" address_symbol="__start_main_settings_page" end_symbol="__stop_main_settings_page" start = "0x0002F000" size="0x1000" />
      </MemorySegment>
    </Root>


    I think you need to add the settingsStore  segment to the Code > Build > Memory Segments in the Common Project settings. I think this should be 

    FLASH RX 0x0 0x30000;RAM RWX 0x20000000 0x6000;settingsStore RX 0x2F000 0x1000

    Best regards

    Bjørn

  • <!DOCTYPE Linker_Placement_File>
    <Root name="Flash Section Placement">
      <MemorySegment name="FLASH" start="$(FLASH_PH_START)" size="$(FLASH_PH_SIZE)">
        <ProgramSection load="no" name=".reserved_flash" start="$(FLASH_PH_START)" size="$(FLASH_START)-$(FLASH_PH_START)" />
        <ProgramSection alignment="0x100" load="Yes" name=".vectors" start="$(FLASH_START)" />
        <ProgramSection alignment="4" load="Yes" name=".init" />
        <ProgramSection alignment="4" load="Yes" name=".init_rodata" />
        <ProgramSection alignment="4" load="Yes" name=".text" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".sdh_soc_observers" inputsections="*(SORT(.sdh_soc_observers*))" address_symbol="__start_sdh_soc_observers" end_symbol="__stop_sdh_soc_observers" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".pwr_mgmt_data" inputsections="*(SORT(.pwr_mgmt_data*))" address_symbol="__start_pwr_mgmt_data" end_symbol="__stop_pwr_mgmt_data" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".sdh_ble_observers" inputsections="*(SORT(.sdh_ble_observers*))" address_symbol="__start_sdh_ble_observers" end_symbol="__stop_sdh_ble_observers" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".sdh_state_observers" inputsections="*(SORT(.sdh_state_observers*))" address_symbol="__start_sdh_state_observers" end_symbol="__stop_sdh_state_observers" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".sdh_stack_observers" inputsections="*(SORT(.sdh_stack_observers*))" address_symbol="__start_sdh_stack_observers" end_symbol="__stop_sdh_stack_observers" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".sdh_req_observers" inputsections="*(SORT(.sdh_req_observers*))" address_symbol="__start_sdh_req_observers" end_symbol="__stop_sdh_req_observers" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".nrf_queue" inputsections="*(.nrf_queue*)" address_symbol="__start_nrf_queue" end_symbol="__stop_nrf_queue" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".nrf_balloc" inputsections="*(.nrf_balloc*)" address_symbol="__start_nrf_balloc" end_symbol="__stop_nrf_balloc" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".cli_command" inputsections="*(.cli_command*)" address_symbol="__start_cli_command" end_symbol="__stop_cli_command" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".crypto_data" inputsections="*(SORT(.crypto_data*))" address_symbol="__start_crypto_data" end_symbol="__stop_crypto_data" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".log_const_data" inputsections="*(SORT(.log_const_data*))" address_symbol="__start_log_const_data" end_symbol="__stop_log_const_data" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".log_backends" inputsections="*(SORT(.log_backends*))" address_symbol="__start_log_backends" end_symbol="__stop_log_backends" />
        <ProgramSection alignment="4" keep="Yes" load="No" name=".nrf_sections" address_symbol="__start_nrf_sections" />
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".cli_sorted_cmd_ptrs"  inputsections="*(.cli_sorted_cmd_ptrs*)" runin=".cli_sorted_cmd_ptrs_run"/>
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".fs_data"  inputsections="*(.fs_data*)" runin=".fs_data_run"/>
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".log_dynamic_data"  inputsections="*(SORT(.log_dynamic_data*))" runin=".log_dynamic_data_run"/>
        <ProgramSection alignment="4" keep="Yes" load="Yes" name=".log_filter_data"  inputsections="*(SORT(.log_filter_data*))" runin=".log_filter_data_run"/>
        <ProgramSection alignment="4" load="Yes" name=".dtors" />
        <ProgramSection alignment="4" load="Yes" name=".ctors" />
        <ProgramSection alignment="4" load="Yes" name=".rodata" />
        <ProgramSection alignment="4" load="Yes" name=".ARM.exidx" address_symbol="__exidx_start" end_symbol="__exidx_end" />
        <ProgramSection alignment="4" load="Yes" runin=".fast_run" name=".fast" />
        <ProgramSection alignment="4" load="Yes" runin=".data_run" name=".data" />
        <ProgramSection alignment="4" load="Yes" runin=".tdata_run" name=".tdata" />
        <ProgramSection alignment="4" keep="Yes" load="No" name=".settingsStore" address_symbol="__start_main_settings_page" end_symbol="__stop_main_settings_page" start = "0x0002F000" size="0x1000" />
      </MemorySegment>
      <MemorySegment name="RAM" start="$(RAM_PH_START)" size="$(RAM_PH_SIZE)">
        <ProgramSection load="no" name=".reserved_ram" start="$(RAM_PH_START)" size="$(RAM_START)-$(RAM_PH_START)" />
        <ProgramSection alignment="0x100" load="No" name=".vectors_ram" start="$(RAM_START)" address_symbol="__app_ram_start__"/>
        <ProgramSection alignment="4" keep="Yes" load="No" name=".nrf_sections_run" address_symbol="__start_nrf_sections_run" />
        <ProgramSection alignment="4" keep="Yes" load="No" name=".cli_sorted_cmd_ptrs_run" address_symbol="__start_cli_sorted_cmd_ptrs" end_symbol="__stop_cli_sorted_cmd_ptrs" />
        <ProgramSection alignment="4" keep="Yes" load="No" name=".fs_data_run" address_symbol="__start_fs_data" end_symbol="__stop_fs_data" />
        <ProgramSection alignment="4" keep="Yes" load="No" name=".log_dynamic_data_run" address_symbol="__start_log_dynamic_data" end_symbol="__stop_log_dynamic_data" />
        <ProgramSection alignment="4" keep="Yes" load="No" name=".log_filter_data_run" address_symbol="__start_log_filter_data" end_symbol="__stop_log_filter_data" />
        <ProgramSection alignment="4" keep="Yes" load="No" name=".nrf_sections_run_end" address_symbol="__end_nrf_sections_run" />
        <ProgramSection alignment="4" load="No" name=".fast_run" />
        <ProgramSection alignment="4" load="No" name=".data_run" />
        <ProgramSection alignment="4" load="No" name=".tdata_run" />
        <ProgramSection alignment="4" load="No" name=".bss" />
        <ProgramSection alignment="4" load="No" name=".tbss" />
        <ProgramSection alignment="4" load="No" name=".non_init" />
        <ProgramSection alignment="4" size="__HEAPSIZE__" load="No" name=".heap" />
        <ProgramSection alignment="8" size="__STACKSIZE__" load="No" place_from_segment_end="Yes" name=".stack"  address_symbol="__StackLimit" end_symbol="__StackTop"/>
        <ProgramSection alignment="8" size="__STACKSIZE_PROCESS__" load="No" name=".stack_process" />
      </MemorySegment>
    </Root>


    This is working. :)

  • I don't know whether the settings flash page will be wiped when it comes to uploading new code (i.e debugging), that needs to be resolved if so.

  • Since load="No" , I do not think that the settings will be overwritten.

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