Anlegen einer neuen section im RAM

[Andreas K. (andrz)]

Hallo,

ich versuche gerade eine internal SRAM Section anzulegen.
Es geht um ein kleines Test-Program mit main & einer Struktur

typedef struct
{
 int aFlag;
 int bFlag;
 int cFlag;
} SharedData;

SharedData g_sharedData  __attribute__((section(".shareddata")));

void main( void )
{
 g_sharedData.aFlag = 100;
 g_sharedData.bFlag = 100;
 g_sharedData.cFlag = 100;
}

Eckdaten:
- uC ATxmega256:
RAM byte addresses:
- IO Register byte address  0x0000 ... 0x0FFF
- mapped Eeprom byte address 0x1000 ... 0x1FFF
- internal SRAM byte address 0x2000 ... 0x5FFF (RAMEND with byte address 
=0x5FFF)
- Harvard Architecture offset: 0x800000

Auszug aus dem angepassten linker file:

MEMORY
{
  text   (rx)   : ORIGIN = 0x000000, LENGTH = 0xffff
  shareddata   (rw!x) : ORIGIN = 0x802000, LENGTH = 0x0200 /* 512 Bytes */
  data   (rw!x) : ORIGIN = 0x802200, LENGTH = 0xfda0 /* 0xffa0 - 0x200 */
 /* data   (rw!x) : ORIGIN = 0x802000, LENGTH = 0xffa0 */
  eeprom (rw!x) : ORIGIN = 0x810000, LENGTH = 64K
  fuse      (rw!x) : ORIGIN = 0x820000, LENGTH = 1K
  lock      (rw!x) : ORIGIN = 0x830000, LENGTH = 1K
  signature (rw!x) : ORIGIN = 0x840000, LENGTH = 1K
}
SECTIONS
{
...

  .text   :
  {
    *(.vectors)
    KEEP(*(.vectors))
    /* For data that needs to reside in the lower 64k of progmem.  */
    *(.progmem.gcc*)
    *(.progmem*)
    . = ALIGN(2);
   
   ...
   }  > text
  .shareddata  : 
  {
     PROVIDE (__shareddata_start = .) ;
    *(.shareddata*)
     PROVIDE (__shareddata_end = .) ;
  }  > shareddata
  .data  :   AT (ADDR (.text) + SIZEOF (.text)) 
  {
     PROVIDE (__data_start = .) ;
    *(.data)
    *(.data*)
    *(.rodata)  /* We need to include .rodata here if gcc is used */
    *(.rodata*) /* with -fdata-sections.  */
    *(.gnu.linkonce.d*)
    . = ALIGN(2);
     _edata = . ;
     PROVIDE (__data_end = .) ;
  }  > data

...
}

Auszug aus dem map file:

Memory Configuration

Name             Origin             Length             Attributes
text             0x00030000         0x0000ffff         xr
shareddata       0x00802000         0x00000200         rw !x
data             0x00802200         0x0000fda0         rw !x
eeprom           0x00810000         0x00010000         rw !x
fuse             0x00820000         0x00000400         rw !x
lock             0x00830000         0x00000400         rw !x
signature        0x00840000         0x00000400         rw !x
*default*        0x00000000         0xffffffff

Auszug aus dem lss file:

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         0000042a  00030000  00030000  00000094  2**1
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
  1 .data         00000076  00802200  00802200  000004c0  2**0
                  CONTENTS, ALLOC, LOAD, DATA
  2 .shareddata   00000002  00802000  00802000  000004be  2**0
                  CONTENTS, ALLOC, LOAD, DATA
  3 .bss          00000004  00802276  00802276  00000536  2**0
                  ALLOC
  4 .stab         000006e4  00000000  00000000  00000538  2**2
                  CONTENTS, READONLY, DEBUGGING
  5 .stabstr      00000090  00000000  00000000  00000c1c  2**0
                  CONTENTS, READONLY, DEBUGGING
  6 .debug_aranges 00000060  00000000  00000000  00000cac  2**0
                  CONTENTS, READONLY, DEBUGGING
  7 .debug_pubnames 000000d4  00000000  00000000  00000d0c  2**0
                  CONTENTS, READONLY, DEBUGGING
  8 .debug_info   00000e31  00000000  00000000  00000de0  2**0
                  CONTENTS, READONLY, DEBUGGING
  9 .debug_abbrev 00000425  00000000  00000000  00001c11  2**0
                  CONTENTS, READONLY, DEBUGGING
 10 .debug_line   0000073e  00000000  00000000  00002036  2**0
                  CONTENTS, READONLY, DEBUGGING
 11 .debug_frame  000000c0  00000000  00000000  00002774  2**2
                  CONTENTS, READONLY, DEBUGGING
 12 .debug_str    0000095f  00000000  00000000  00002834  2**0
                  CONTENTS, READONLY, DEBUGGING
 13 .debug_loc    00000093  00000000  00000000  00003193  2**0
                  CONTENTS, READONLY, DEBUGGING
 14 .debug_pubtypes 000001d4  00000000  00000000  00003226  2**0
                  CONTENTS, READONLY, DEBUGGING

Kompilieren lässt es sich. Sobald ich jedoch die SW flashen will (aus 
dem WinAvr Studio 5.1) bekomme ich folgende Fehlermeldung:
"Some sections of the file provided does not fit within in the device 
memory"
Woran liegt es?

Danke im Voraus für Eure Hilfe.

[Jim M. (turboj)]

Muss ".shareddata" beim Start initialisiert werden? So wie Du es 
geschrieben hast müsste der Programmer den RAM programmieren - was 
natürlich wenig sinnvoll erscheint.

Wenn es nicht initialisiert werden muss:

.shareddata (NOLOAD) : 
  {
     PROVIDE (__shareddata_start = .) ;
    *(.shareddata*)
     PROVIDE (__shareddata_end = .) ;
  }  > shareddata

Anderenfalls muss man wie bei .data dafür sorgen dass die Initialdaten 
im Flash landen.