Posted on September 27, 2016 at 15:17Hey guys,
I have a problem with defining a section for the external SDRAM on the STM32F746-Disco. I red many posts in different forums but I didn't find the way to a working code.
I initialized the SDRAM in the SystemInit() and it's working because I can use it in the main() function without additional initialisation. Afterwords I took the linker script and added a memory entry like followed:
MEMORY
{
FLASH (rx) : ORIGIN = 0x8000000, LENGTH = 1024K
RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 320K
SDRAM (xrw) : ORIGIN = 0xC0000000, LENGTH = 8M
}
and a section entry like this:
...
.sdram_data (NOLOAD) :
{
. = ALIGN(8);
_sdram_data_begin = .;
*(.sdram_data)
*(.sdram_data*)
. = ALIGN(8);
_sdram_data_end = .;
} >SDRAM
...
When I now declare a variable in the main file
const char picture1
http://www.openstm32.org/480%2a272%2a3
]
__attribute__((section(''.sdram_data'')));
and want to fill it afterwards with information
picture1[] = {
0x00, 0xFF, 0xFF;
0x00, 0xFF, 0xFF;
0x00, 0xFF, 0xFF;
...
};
I get the error:
../src/main.c:53:1: warning: data definition has no type or storage class
picture1[] = {
^
../src/main.c:53:1: warning: type defaults to 'int' in declaration of 'picture1'
http://www.openstm32.org/-Wimplicit-int
../src/main.c:53:1: error: conflicting types for 'picture1'
../src/main.c:52:12: note: previous declaration of 'picture1' was here
const char picture1
http://www.openstm32.org/480%2a272%2a3
__attribute__((section(''.sdram_data'')));
When I declare the variable as followed I don't get an error but it's also not working.
__attribute__((section(''.sdram_data'')))
const char picture1[] =
{
0x00, 0xFF, 0xFF;
0x00, 0xFF, 0xFF;
0x00, 0xFF, 0xFF;
...
};
I hope anybody of you can help me.
#sdram #gcc-linker-ccm #memory-sections
