Configuring the Vector Table offset when using the Kinetis Bootloader and KDS

Question

I'm currently working on setting up the Kinetis Bootloader for the FRDM board, in order to use it as a system for wireless OTA updates. Seeing as the bootloader lives in the flash memory, the standard way to keep the bootloader reusable is to write your program to the flash memory starting at an address after the bootloader code. The example that comes with the Kinetis Bootloader code is a blinky program that is supposed to be written starting at address 0xA000.

However, I can't figure out how to set up the offset in my own code so that it works correctly when written at an adress other than 0x0000. I'm using the Kinetis Development Studio with gcc, does anyone else have experience making their own user app at a custom offset into the program?

Former Member · Accepted Answer

Okay, so when using the Processor Expert configuration menu, it allows you to change the address and size of both interrupts and text to whatever location you want. HOWEVER: Processor expert also generates another section in the linker file, m_flash_config, which defaults to the address of 0x000400. So if this isn't changed as well, you get a file with a KB of empty data, 16 bytes of flash configuration data, and then empty data until your program's address. This obviously doesn't work and makes debuggers cry. So, if I wanted to change the offset from 0x0000 (the default), to 0xA000 (the default with a bootloader), the solution is to open the ProcessorExpert.ld linker file in your Project_Settings file, and change the memory section from this: MEMORY {
 m_interrupts (RX) : ORIGIN = 0x00000000, LENGTH = 0x00000400
 m_text (RX) : ORIGIN = 0x00000410, LENGTH = 0x000FFBF0
 m_interrupts_ram (RW) : ORIGIN = 0x1FFF0000, LENGTH = 0x00000400
 m_data_1FFF0400 (RW) : ORIGIN = 0x1FFF0400, LENGTH = 0x0000FC00
 m_data (RW) : ORIGIN = 0x20000000, LENGTH = 0x00030000
 m_flash_config (RX) : ORIGIN = 0x00000400, LENGTH = 0x00000010
} To this: MEMORY {
 m_interrupts (RX) : ORIGIN = 0x0000A000, LENGTH = 0x00000400
 m_text (RX) : ORIGIN = 0x0000A410, LENGTH = 0x000F5BF0
 m_interrupts_ram (RW) : ORIGIN = 0x1FFF0000, LENGTH = 0x00000400
 m_data_1FFF0400 (RW) : ORIGIN = 0x1FFF0400, LENGTH = 0x0000FC00
 m_data (RW) : ORIGIN = 0x20000000, LENGTH = 0x00030000
 m_flash_config (RX) : ORIGIN = 0x0000A400, LENGTH = 0x00000010
} (note that m_text's size had to be reduced by the size of the offset, as to not overwrite m_interrupts_ram) (note also that this .ld file will be overwritten each time you generate files via processor expert) After that, loading the modified version via bootloader into memory at offset 0xA000 should work as usual! Good luck!