SDRAM and a global struct.

[Hector_R]

Hi.

I am using TouchGFX and it works fine,

My MCU is STM32H743

 

But when I use the SDRAM for other things the code does not work.

My question is:

Can I use struct in the  SDRAM.?

 

I have this one in my c file.

 

 

SD_CARD SdCard __attribute__((section("\"SDCardSection\""))) __attribute__((aligned(4)));

 

 

In my h file as follows:

 

 

 

typedef struct {
	char Name[256];
	char Path[1000];
	char File[2000];
	uint8_t LogicalDrive;
}SD_CARD;
extern SD_CARD SdCard __attribute__((section("\"SDCardSection\""))) __attribute__((aligned(4)));

 

 

 My Linker file is as follows:

 

 

/* Entry Point */
ENTRY(Reset_Handler)

/* Highest address of the user mode stack */
_estack = ORIGIN(RAM_D1) + LENGTH(RAM_D1); /* end of RAM */
/* Generate a link error if heap and stack don't fit into RAM */
_Min_Heap_Size = 0x400; /* required amount of heap */
_Min_Stack_Size = 0x800; /* required amount of stack */

/* Specify the memory areas */
MEMORY
{
 FLASH (rx) : ORIGIN = 0x08000000, LENGTH = 2048K
 DTCMRAM (xrw) : ORIGIN = 0x20000000, LENGTH = 128K
 RAM_D1 (xrw) : ORIGIN = 0x24000000, LENGTH = 512K
 RAM_D2 (xrw) : ORIGIN = 0x30000000, LENGTH = 288K
 RAM_D3 (xrw) : ORIGIN = 0x38000000, LENGTH = 64K
 ITCMRAM (xrw) : ORIGIN = 0x00000000, LENGTH = 64K
 QUADSPI (r) : ORIGIN = 0x90000000, LENGTH = 16M
 SDRAM (xrw) : ORIGIN = 0xC0000000, LENGTH = 32M 
}

etc
etc
etc
 .ARM.attributes 0 : { *(.ARM.attributes) }
 
 BufferSection (NOLOAD) :
 {
 *(Video_RGB_Buffer Video_RGB_Buffer.*)
 *(.gnu.linkonce.r.*)
 . = ALIGN(0x4);

 *(TouchGFX_Framebuffer TouchGFX_Framebuffer.*)
 *(.gnu.linkonce.r.*)
 . = ALIGN(0x4);
 } >SDRAM
 
 SDCardSection (NOLOAD) :
 {
 *(SDCardSection SDCardSection .*)
 *(.gnu.linkonce.r.*)
 . = ALIGN(0x4);
 } >SDRAM

 

 

 

 Best Regards.

[GaetanGodart]

Hello @Hector_R and welcome to the community!

 

I do not see why you could not use a struct in the SDRAM.

I do not think you need 

extern SD_CARD SdCard __attribute__((section("\"SDCardSection\""))) __attribute__((aligned(4)));

 in your header file. Just declare the type in the source file.

 

Are you able to use your SDRAM when you don't use the structure?

 

Regards,

[mƎALLEm]

Hello,

You've already declared and relocated it in SDRAM in the c file:

SD_CARD SdCard __attribute__((section("\"SDCardSection\""))) __attribute__((aligned(4)));

No need to relocate it again in the header file: 

typedef struct {
	char Name[256];
	char Path[1000];
	char File[2000];
	uint8_t LogicalDrive;
}SD_CARD;
extern SD_CARD SdCard;

The linker knows by the key "extern" it's the same variable you've declared in .c file.

[Hector_R]

Hello Gaetan.

I need to add the structure as an extern because those variables are used in other files. (from TouchGFX)

This works well.

My .c file.

// My structure
SD_CARD SdCard

In my .h file

typedef struct {
	char Name[256];
	char Path[1000];
	char File[2000];
	uint8_t LogicalDrive;
}SD_CARD;
extern SD_CARD SdCard;

 As you can see when

But I would use the SDRAM  because I need to add big buffers to display files (SD CARD file names)

But this way the display does not work.

typedef struct {
	char Name[256];
	char Path[1000];
	char File[2000];
	uint8_t LogicalDrive;
}SD_CARD;
extern SD_CARD SdCard __attribute__((section("\"SDCardSection\""))) __attribute__((aligned(4)));

 

[mƎALLEm]

As I said you need to declare and relocate that structure in the c file:

SD_CARD SdCard __attribute__((section("\"SDCardSection\""))) __attribute__((aligned(4)));

Then export it the header file without any relocation:

typedef struct {
	char Name[256];
	char Path[1000];
	char File[2000];
	uint8_t LogicalDrive;
}SD_CARD;
extern SD_CARD SdCard;

[Hector_R]

Hello Friend!.

Yes, I have tested it right now.

But the problem is still there.

 

If I use a simple buffer it works, for example:

.c file

char SdCard_Name[256] __attribute__((section("\"SDCardSection\""))) __attribute__((aligned(4)));

 

extern SdCard_Name[256];

 

[Hector_R]

Hi there.

The problem was that TouchGFX uses Unicode.

I was using char buffer and pointers to update the buffer of a scrollWheel.

But TouchGFX describes that we should use the Unicode library.

So,  I updated my buffers to datatype uint16_t, and then used the Unicode library.

void CustomContainer2_1::UpdateText(uint16_t value)
{
	Unicode::snprintf(textArea1Buffer, TEXTAREA1_SIZE, "%s", &SdCard.File);
...
...
...
...
 textArea1.invalidate();
}