How to Use a Variable in SRAM to Communicate between Bootloader and Application

Chao · ‎2024-09-05

Hi,

I have a bootloader for my application, at the moment they exchange their working status by flash write. I think a better way is to declare a variable in RAM with the same address in both bootloader and application. Someone mentioned, in a post, that the linker script could be used for this, but didn't give an example.

Anybody could do me a favour and show me an example ? Thanks.

SofLit · ‎2024-09-05

@Chao wrote:

Someone mentioned, in a post, that the linker script could be used for this, but didn't give an example.

Anybody could do me a favour and show me an example ? Thanks.

Using __attribute . See this link: https://www.openstm32.org/Using%2BCCM%2BMemory

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MM..1 · ‎2024-09-05

Maybe we require info how working status you mean... And most simple method to share is move start RAM +somethink for example 0x20000020 and use direct pointers to 0-1F arrea.

SofLit · ‎2024-09-05

Yes @MM..1 it could be also a solution.

#define COMMON_VAR_ADDRESS 0x2000XXXX /* Define a common RAM address */

uint32_t* common_var = (uint32_t*)COMMON_VAR_ADDRESS; /* Declare a pointer at that address */
*common_var = y; /* access to that address */

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