About section placement of "SEGGER Embedded Studio"

[takashina hiroki]

I have a question about "SEGGER Embedded Studio for ARM V4.12".

I want to place the section of the FLASH area arbitrarily.
And, for example, I want to place the following constants in that section.
(For example, 0x77FF0 to 0x77FF2 section layout)

const uint8_t table_data [3] = {1, 2, 3};

Please tell me how.

[Simonr]

Hi

Please check out this post, where a SEGGER employee describes how to do just that.

Best regards,

Simon

[takashina hiroki]

Thank you for answering.
I will check it.

[takashina hiroki]

I changed "flash_placement.xml" as follows.

<!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)-$(FLASH_PH_START)" />
    [...]
	<ProgramSection alignment="4" load="No" name=".sp_flash" start="0x00077FF6" size="0x00000006" />
  </MemorySegment>
  <MemorySegment name="RAM" start="$(RAM_PH_START)" size="$(RAM_PH_SIZE)">
    [...]
  </MemorySegment>
</Root>

In addition, I added the following processing.

const uint8_t flash_test[1] __attribute__((section (".sp_flash"))) __attribute__((used)) = {0xBC};

I thought "0xBA" was written at the address 0x00077FF6.
However, I confirmed that it was not written at that address.

Please tell me the cause and countermeasures.

[Simonr]

Hi

First of all, I see that you've set load="No" where this should be Yes when storing to flash. 

You can use one of our DFU examples as a reference to see how for example the bootloader is set up to start in the correct flash address. The flash placement file for one of the DFU examples can be found in this path: ..\nRF5_SDK_15.3.0_59ac345\examples\dfu\open_bootloader\pca10056_usb\ses\flash_placement.xml

Best regards,

Simon

[takashina hiroki]

By setting keep = "Yes" load = "Yes", it was possible to place in the section.
Thank you for answering.