topic Re: s9keaz128 Variable Address Allocation in Kinetis Microcontrollers

s9keaz128 Variable Address Allocation

Tom77854 — Mon, 20 Apr 2026 09:05:57 GMT

Hello, experts.

It's about linker scripts. l want to place the data's LMA at a fixed address such as 0x00010000 instead of following right after the text. So l modify the linker scripts and startup code. It really generated the hex what l wanted. But when l debug, it doesn't work and jump to default ISR.

this is what l modify. I will put the original code in the attachment.

linker scripts

__DATA_ROM = 0x00010000; /* Symbol is used by startup for data initialization */

startup.s

ldr r1, =__DATA_ROM
ldr r2, =__data_start__
ldr r3, =__data_end__

Re: s9keaz128 Variable Address Allocation

Celeste_Liu — Thu, 23 Apr 2026 10:46:47 GMT

Hello @Tom77854 ,

Thanks for your post. I’ve noticed your case and will need some time to look into it further. I’ll keep you informed of any updates as soon as possible. If there is any progress on your side, please feel free to share it with me.

Celeste

Re: s9keaz128 Variable Address Allocation

Celeste_Liu — Mon, 27 Apr 2026 06:47:21 GMT

Hello @Tom77854 ,

I think the issue comes from an incorrect definition location of __DATA_ROM. The linker does not automatically reserve space in FLASH just because AT() is specified.
To verify this, you can check the generated .map file to see whether any section actually occupies address 0x00010000. Alternatively, you can directly inspect the Flash contents in the debugger—for example, by checking whether there is valid data at 0x00010000 in the debugger’s Memory View.
My recommended approach is to define a dedicated ROM region and assign a section to it, for example:

MEMORY

{

FLASH (RX) : ORIGIN = 0x00000000, LENGTH = 128K

DATA_ROM (RX) : ORIGIN = 0x00010000, LENGTH = 8K

SRAM (RW) : ORIGIN = 0x1FFFF000, LENGTH = 16K

}

.data_rom :

{

__DATA_ROM = .;

KEEP(*(.data_init))

} > DATA_ROM

.data : AT(__DATA_ROM)

{

__data_start__ = .;

*(.data)

*(.data*)

__data_end__ = .;

} > SRAM

Hope it helps.

Celeste