I successfully create 0x40 bytes on "not initialized" area on top of AXI RAM (0x24000000) for CORE M7 and on top of AHB SRAM1 (0x30000000) in order to info about a fault immediately before reset MCU (for example if a trap of NULL pointer is triggered).
On AXI RAM no problem, but on AHB SRAM1 I don't get the same data I put before reset. If I move (by linker scripts) the M4 data from AHB SRAM1 to AXI RAM I don't get problems.
Situation is:
- Clean project generated by CUBEMX
- No cache enable
- Simple modification of linker script
I also note that if I use only uint32_t data, I don't get problems!
Any ideas about?
Attached the example!
My M4 linker script (only important parts)
MEMORY
{
ERRORS_M4 (xrw) : ORIGIN = 0x10000000, LENGTH = 0x40
RAM (xrw) : ORIGIN = 0x10000040, LENGTH = 288K - 0x40
FLASH (rx) : ORIGIN = 0x08100000, LENGTH = 1024K
}
.
.
.
.errors (NOLOAD) :
{
. = ALIGN(4);
*(.errors) /* .errors sections */
. = ALIGN(4);
} >ERRORS_M4
Struct declaration:
#pragma pack(1)
typedef struct
{
char module[50];
uint16_t line;
uint32_t address;
uint32_t date_time;
uint32_t crc;
} RECORD;
#pragma pack()
static RECORD Error_Ram_Record __attribute__((section(".errors")));
