Problem using S32DS of debug and debug_ram

jerrytomlee — Thu, 15 Mar 2018 06:18:29 GMT

__attribute__ ((section(".text")))
int main(void)
{
int counter = 0;
short int your = 0;

I have add a declaration of "short int your = 0;" in the example "eTimer_MPC5744P" in S32DS.

I am using the newest S32DS 2017 R1 .

In debug model, it works well.

In debug_Ram model, it didn't work.

The Disassembly showed:

236 short int your = 0;
40002d00: se_li r7,0
40002d02: se_sth r7,12(r31)

And it failed at se_sth every time,and it show No source available kind of things.

So I wonder why?

Re: Problem using S32DS of debug and debug_ram

martin_kovar — Thu, 15 Mar 2018 14:01:38 GMT

Hello Jerry,

the problem is hidden in startup code. When you run example from flash, local DMEM is initialized by startup code. In this part of memory is placed stack, which is used for local variable storing.

But when you run example from RAM, this part of memory is not initialized because there is conditional compilation. When you try to write half word (short int) into uninitialized memory, ECC error is created.

Please use the following part of startup, instead of original one:

#ifdef START_FROM_FLASH

;#***************************** Initialise SRAM ECC ***************************/
;# Store number of 128Byte (32GPRs) segments in Counter
e_lis       r5, __SRAM_SIZE@h # Initialize r5 to size of SRAM (Bytes)
e_or2i      r5, __SRAM_SIZE@l
e_srwi      r5, r5, 0x7         # Divide SRAM size by 128
mtctr       r5                  # Move to counter for use with "bdnz"

;# Base Address of the internal SRAM
e_lis r5, __SRAM_BASE_ADDR@h
e_or2i r5, __SRAM_BASE_ADDR@l

;# Fill SRAM with writes of 32GPRs
sram_loop:
    e_stmw      r0,0(r5)            # Write all 32 registers to SRAM
    e_addi      r5,r5,128           # Increment the RAM pointer to next 128bytes
    e_bdnz      sram_loop           # Loop for all of SRAM

#endif

;#************************ Initialise Local Data SRAM ECC *********************/
;# Store number of 128Byte (32GPRs) segments in Counter
e_lis       r5, __LOCAL_DMEM_SIZE@h # Initialize r5 to size of SRAM (Bytes)
e_or2i      r5, __LOCAL_DMEM_SIZE@l
e_srwi      r5, r5, 0x7         # Divide SRAM size by 128
mtctr       r5                  # Move to counter for use with "bdnz"

;# Base Address of the Local SRAM
e_lis r5, __LOCAL_DMEM_BASE_ADDR@h
e_or2i r5, __LOCAL_DMEM_BASE_ADDR@l

;# Fill Local SRAM with writes of 32GPRs
ldmem_loop:
    e_stmw      r0,0(r5)            # Write all 32 registers to SRAM
    e_addi      r5,r5,128           # Increment the RAM pointer to next 128bytes
    e_bdnz      ldmem_loop          # Loop for all of SRAM

In original startup code, #endif is placed below ldmem_loop section.

Regards,

Martin

Re: Problem using S32DS of debug and debug_ram

jerrytomlee — Fri, 16 Mar 2018 01:56:47 GMT

Thanks a lot for your help!

topic Problem using S32DS of debug and debug_ram in S32 Design Studio

Problem using S32DS of debug and debug_ram

Re: Problem using S32DS of debug and debug_ram

Re: Problem using S32DS of debug and debug_ram