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Dear support,
During a debug session with CCSv6 on my project, my initialized global variables doesn't get initialized at startup because the flashing tool of CCSv6 seems to not load those data in flash. I'm using as usual the following code to populate those variables at startup:
pul_src = &_etext;
for(pul_dst = &_data; pul_dst < &_edata;) {
*pul_dst++ = *pul_src++;
}The memory content at _etext is filled with 0 and thus my global variables get initialized with 0.
Here is the linker script I'm currently using:
MEMORY
{
FLASH (RX) : ORIGIN = 0x00200000, LENGTH = (0x00080000 - 44)
FLASH_CCA (RX) : ORIGIN = (0x00200000 + (0x00080000 - 44)), LENGTH = 44
NRSRAM (RWX) : ORIGIN = 0x20000000, LENGTH = 0x00004000
SRAM (RWX) : ORIGIN = 0x20004000, LENGTH = 0x00004000
}
/* heap section */
_eheapdata = ORIGIN(SRAM) + LENGTH(SRAM);
/* We put the usb related init and non-init data in the non-retention SRAM.
The Load Memory Address (LMA) is stored in a variable and used by the program
to initiliaze the usb data once needed. */
SECTIONS
{
.text :
{
_text = .;
KEEP(*(.vectors))
*(.text*)
*(.rodata*)
_etext = .;
} > FLASH= 0
.socdata (NOLOAD) :
{
*(.udma_channel_control_table)
} > SRAM
.data :
{
_data_lma = LOADADDR(.data);
_data = .;
*(EXCLUDE_FILE(*usb*.o) .data*)
_edata = .;
} > SRAM AT > FLASH
.ARM.exidx :
{
*(.ARM.exidx*)
} > FLASH
.bss :
{
_bss = .;
*(EXCLUDE_FILE(*usb*.o) .bss*)
*(EXCLUDE_FILE(*usb*.o) COMMON)
. = ALIGN(4);
_ebss = .;
_heapdata = ABSOLUTE(.);
} > SRAM
.nrdata :
{
_nrdata_lma = LOADADDR(.nrdata);
_nrdata = .;
*(.nrdata*)
*usb*.o(.data)
_enrdata = .;
} > NRSRAM AT > FLASH
.nrbss (NOLOAD) :
{
_nrbss = .;
*(.nrbss*)
*usb*.o(.bss COMMON)
_enrbss = .;
} > NRSRAM
.flashcca :
{
KEEP(*(.flashcca))
} > FLASH_CCA
}
By looking at the symbol table generated by arm-none-eabi-nm.exe I noticed that the initialized data are effectively present after the .text section (0x0021e098-0x0021db9a = 1278):
0021db9a A _data_lma 0021db9a T _etext 0021e098 A _nrdata_lma 0027ffd4 0000002c R __cca
CCSv6 appear to be unconcerned about what is coming after the .text section during a debug session and won't load this part in flash.
Note that everything works fine and I'm able to run my program when I'm flashing the device with the Flash Programmer 2 software. After that, if a run a debug session by loading only the symbols, the content after the .text section are not zero and my global variables get initialized properly.
Thanks a lot for your help if there is a solution to this problem.
Yes of course but I don't initialize this second data section at startup. I do it latter in the code with a function this isn't a problem. To see the changes I'm directly watching the memory with the Memory Browser. Here the issue by images:
Program loaded by the debugger:
Program loaded with external flasher and then debug by loading only symbols:
(edit)
Further note: Now that there is a flashing verbose output option in v6.1.0 I can notice that the data are effectively loaded, but then why would this area be filled with 0? When I flash the device with an external tool I use the arm-none-eabi-objcopy.exe program to create a binary file from the .out file. This latter contains with no doubt the the initialized data because the program works in that case.
Cortex_M3_0: GEL Output: Memory Map Initialization Complete. Cortex_M3_0: Writing Flash @ Address 0x00200000 of Length 0x00007ff0 Cortex_M3_0: Writing Flash @ Address 0x00207ff0 of Length 0x00007ff0 Cortex_M3_0: Writing Flash @ Address 0x0020ffe0 of Length 0x00007ff0 Cortex_M3_0: Writing Flash @ Address 0x00217fd0 of Length 0x00002ebe Cortex_M3_0: Writing Flash @ Address 0x0021ae8e of Length 0x000004f0 Cortex_M3_0: Writing Flash @ Address 0x0021b380 of Length 0x00000008 Cortex_M3_0: Writing Flash @ Address 0x0021b388 of Length 0x00000060 Cortex_M3_0: Writing Flash @ Address 0x0027ffd4 of Length 0x0000002c Cortex_M3_0: GEL Output: CPU Reset.
