stm32h735 HyperRAM extern memory

[HispaEmo]

Hello friends at ST,

I'm trying to configure the external memory on an STM32H375 board using CubeIDE, but I'm not achieving success.

Let me explain how I'm doing it: I enable OCTOSPI2, set it to HyperBus mode, choose port 2, and configure the corresponding pins.

Regarding these options, I'm not quite sure which ones to choose:

This is my linker file:

If I put ">RAM_D1 AT> RAM_D4," the data is not assigned. If I put "RAM_D4," the data is assigned, but when I load it onto the board, it doesn't work.

new some help

thank U

[FBL]

Hello @HispaEmo 

Would you share your schematics? datasheet of your memory? In linker script, are you sure about memory size? 128000 KB?

---

@HispaEmo wrote:

Regarding these options, I'm not quite sure which ones to choose:

---

About options, you need to refer the specifications in the reference manual to learn about them. These modes are fundamental to make it work.

[LCE · Accepted solution]

I just use the HyperRAM (on H735 discovery kit) for some special variables / buffers, which are placed there with the <attribute> thingy.

Linker script:

OSPI2_D1(xrw)	: ORIGIN = 0x70000000, LENGTH = 0x1000000	/* OCTOSPI 2 */

later on in SECTIONS:

/* external A2IP buffer section */
.A2IpBufExtSection (NOLOAD):
{
	. = ALIGN(8);
	*(.A2IpBufExtSection)
	*(.A2IpBufExtSection*)
	. = ALIGN(8);
} >OSPI2_D1

Variable declaration in *.c / *.h:

*.c:
/* sA2IpBuf: A2IP packet buffers in EXTernal OCTOSPI SRAM */
/* memory: OCTOSPI 2 */
__ALIGN_BEGIN sA2IpBuf_t sA2IpBuf[A2IP_BUF_NUM] __attribute__((section(".A2IpBufExtSection"))) __attribute__((aligned(8))) __ALIGN_END;

*.h:
/* memory: OCTOSPI 2 */
extern __ALIGN_BEGIN sA2IpBuf_t sA2IpBuf[A2IP_BUF_NUM] __attribute__((section(".A2IpBufExtSection"))) __attribute__((aligned(8))) __ALIGN_END;

Setup is done without HAL, clocked with 100 MHz.

Works like a charm!

[HispaEmo]

Hello @LCE and @FBL 

Thank you very much for your response.

I have been implementing your solution, and I can't get it to work.

I have some questions for you:

1- When you mention activating the clock, are you referring to the clock of RAM_D1 or OCTOSPI2, or both?

Do I activate them in the system_stm32h7xx.c file?

In the void SystemInit(void):

(...)

_HAL_RCC_D2SRAM1_CLK_ENABLE();

__HAL_RCC_OSPI2_CLK_ENABLE();

2- How can I configure the frequency of these clocks?

3- In the .ld file, what I want to relocate is the .bss and ethernet_data from RAM_D1 to OSPI2_D1. Is this possible?

/* Specify the memory areas */
MEMORY
{
  ITCMRAM (xrw)    : ORIGIN = 0x00000000,   LENGTH = 64K
  DTCMRAM (xrw)    : ORIGIN = 0x20000000,   LENGTH = 128K
  FLASH    (rx)    : ORIGIN = 0x08000000,   LENGTH = 1024K
  RAM_D1  (xrw)    : ORIGIN = 0x24000000,   LENGTH = 320K
  RAM_D2  (xrw)    : ORIGIN = 0x30000000,   LENGTH = 32K
  RAM_D3  (xrw)    : ORIGIN = 0x38000000,   LENGTH = 16K

}

/* Define output sections */
SECTIONS
{
  /* The startup code goes first into FLASH */
  .isr_vector :
  {
    . = ALIGN(4);
    KEEP(*(.isr_vector)) /* Startup code */
    . = ALIGN(4);
  } >FLASH

  /* The program code and other data goes into FLASH */
  .text :
  {
    . = ALIGN(4);
    *(.text)           /* .text sections (code) */
    *(.text*)          /* .text* sections (code) */
    *(.glue_7)         /* glue arm to thumb code */
    *(.glue_7t)        /* glue thumb to arm code */
    *(.eh_frame)

    KEEP (*(.init))
    KEEP (*(.fini))

    . = ALIGN(4);
    _etext = .;        /* define a global symbols at end of code */
  } >FLASH

  /* Constant data goes into FLASH */
  .rodata :
  {
    . = ALIGN(4);
    *(.rodata)         /* .rodata sections (constants, strings, etc.) */
    *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
    . = ALIGN(4);
  } >FLASH

  .ARM.extab   : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
  .ARM : {
    __exidx_start = .;
    *(.ARM.exidx*)
    __exidx_end = .;
  } >FLASH

  .preinit_array     :
  {
    PROVIDE_HIDDEN (__preinit_array_start = .);
    KEEP (*(.preinit_array*))
    PROVIDE_HIDDEN (__preinit_array_end = .);
  } >FLASH

  .init_array :
  {
    PROVIDE_HIDDEN (__init_array_start = .);
    KEEP (*(SORT(.init_array.*)))
    KEEP (*(.init_array*))
    PROVIDE_HIDDEN (__init_array_end = .);
  } >FLASH

  .fini_array :
  {
    PROVIDE_HIDDEN (__fini_array_start = .);
    KEEP (*(SORT(.fini_array.*)))
    KEEP (*(.fini_array*))
    PROVIDE_HIDDEN (__fini_array_end = .);
  } >FLASH

  /* used by the startup to initialize data */
  _sidata = LOADADDR(.data);

  /* Initialized data sections goes into RAM, load LMA copy after code */
  .data :
  {
    . = ALIGN(4);
    _sdata = .;        /* create a global symbol at data start */
    *(.data)           /* .data sections */
    *(.data*)          /* .data* sections */
    *(.RamFunc)        /* .RamFunc sections */
    *(.RamFunc*)       /* .RamFunc* sections */

    . = ALIGN(4);
    _edata = .;        /* define a global symbol at data end */
  } >RAM_D1 AT> FLASH

  /* Uninitialized data section */
  . = ALIGN(4);
  .bss :
  {
    /* This is used by the startup in order to initialize the .bss section */
    _sbss = .;         /* define a global symbol at bss start */
    __bss_start__ = _sbss;
    *(.bss)
    *(.bss*)
    *(COMMON)

    . = ALIGN(4);
    _ebss = .;         /* define a global symbol at bss end */
    __bss_end__ = _ebss;
  } >RAM_D1 

  /* User_heap_stack section, used to check that there is enough RAM left */
  ._user_heap_stack :
  {
    . = ALIGN(8);
    PROVIDE ( end = . );
    PROVIDE ( _end = . );
    . = . + _Min_Heap_Size;
    . = . + _Min_Stack_Size;
    . = ALIGN(8);
  } >RAM_D1
  


  

  /* Remove information from the standard libraries */
  /DISCARD/ :
  {
    libc.a ( * )
    libm.a ( * )
    libgcc.a ( * )
  }

  .ARM.attributes 0 : { *(.ARM.attributes) }
}

Thank you in advance.
need your help.

[LCE]

> 1- When you mention activating the clock, are you referring to the clock of RAM_D1 or OCTOSPI2, or both?

The OSPI clock is activated in my source code in the function void PeriphCommonClock_Config(void) in the main file:

/* OSPI = D1HCLK = HCLK3 = 1/2 CPU */
PeriphClkInitStruct.PeriphClockSelection |= RCC_PERIPHCLK_OSPI;
PeriphClkInitStruct.OspiClockSelection = RCC_OSPICLKSOURCE_D1HCLK;

So check your main file 

Probably there's something in the CubeMX clock config tree?

> 2- How can I configure the frequency of these clocks?

I think you do NOT want to play with changing internal RAM clocks.
For OSPI clock, check Cube?

There is also a clock prescaler in the OSPI peripheral in DCR2:

/* DCR2:
 *	WRAPSIZE 	= 0 	wrapped read OFF
 *	PRESCALER 	= 1 	divide by 2 -> 100 MHz = max at 3.3V
 */
OCTOSPI2->DCR2 = 	(OSPI_HYPERRAM_WRAP_ZERO << OCTOSPI_DCR2_WRAPSIZE_Pos) |
						((OSPI_HYPERRAM_CLK_DIV - 1) << OCTOSPI_DCR2_PRESCALER_Pos);

> 3- In the .ld file, what I want to relocate is the .bss and ethernet_data from RAM_D1 to OSPI2_D1. Is this possible?

I don't know. I just use the HyperRam as described above, with the "attributed" buffers.

Anyway, moving everything from AXI RAM to external RAM sounds "dangerous" to me.

Ethernet:

I think the descriptors should stay in RAM_D2.