Electronic – STM32F103 flash memory start address

linkerstm32stm32f10x

I'm trying to write a linker script for my first firmware for STM32F103C8T6 microcontroller. I have an example script that works. What I'm trying to understand is why it works.

The linker script I have defines two memory locations: 

MEMORY
{
    FLASH (rx) : ORIGIN = 0x08000000, LENGTH = 64K
    RAM (rwx)  : ORIGIN = 0x20000000, LENGTH = 32K
}

Official STM32 programming manual section 2.2 states that "Code" memory section starts with address 0x00000000. The next section is RAM, which is 0x20000000, just like stated in my linker script.

Where the FLASH origin value 0x08000000 comes from?

Best Answer

The linked programming manual shows a code region starting at 0x00000000 which is 0.5GB in size. The datasheet for the part shows flash memory at 0x08000000 onwards.

0x00000000 is where the address for the initial stack pointer is, with 4bytes on being the address of the first instruction to execute.

On the stm32 the area mapped to 0x00000000 is changed based on boot pin setting to allow execution of user loaded code, or running a built in bootloader.

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