Hello,
I'm tring to build the TIVA Bootloader for the above processor. The loader is built but the code is not copied from the FLASH to the SRAM. I've a project very similar to the bootloader of the TivaWare 2.1.4.178 .
I'm using CCS Version: 10.3.1.00003 and the compiler version is TI v20.2.4.LTS.
After I've programmed the processor, I can find in the FLASH the vector table, but the following data does not look like the assembly code. The reset vector point to uninitialized FLASH. I suspect that part of the code to copy is not present in the FLASH.
If I take this part of the bl_startup_ccs.s :
;;*****************************************************************************
;;
;; This portion of the file goes into the text section.
;;
;;*****************************************************************************
.word 0x12345678
.text
;;*****************************************************************************
;;
;; Initialize the processor by copying the boot loader from flash to SRAM, zero
;; filling the .bss section, and moving the vector table to the beginning of
;; SRAM. The return address is modified to point to the SRAM copy of the boot
;; loader instead of the flash copy, resulting in a branch to the copy now in
;; SRAM.
;;
;;*****************************************************************************
.ref bss_run
bss_start .word bss_run
.ref __STACK_TOP
bss_end .word __STACK_TOP
.thumbfunc ProcessorInit
ProcessorInit: .asmfunc
;;
;; Copy the code image from flash to SRAM.
;;
movs r0, #0x0000
movs r1, #0x0000
movt r1, #0x2000
ldr r2, bss_start
And I compare with a dump of the FLASH :
0000003a: 2000 movs r0, #0
0000003c: 06A3 lsls r3, r4, #0x1a
0000003e: 2000 movs r0, #0
00000040: 06A3 lsls r3, r4, #0x1a
00000042: 2000 movs r0, #0
00000044: 5678 ldrsb r0, [r7, r1]
00000046: 1234 asrs r4, r6, #8
00000048: F1AD0D08 sub.w r13, r13, #8
0000004c: 9000 str r0, [r13]
0000004e: BA00 rev r0, r0
00000050: 4770 bx r14
00000052: 9800 ldr r0, [r13]
00000054: 1C40 adds r0, r0, #1
00000056: B002 add r13, #8
00000058: 4770 bx r14
0000005a: B508 push {r3, r14}
One can see my ".word" with the value 12345678 (in bold), but the following code should be "movs..."
The compiler issue warnings regarding this initialization :
warning #10278-D: LOAD placement specified for section
".text:rtsv7M4_T_le_v4SPD16_eabi.lib<memset_t2.asm.obj>". This section
contains decompression routines required for linker generated copy tables
and C/C++ auto-initialization. Must ensure that this section is copied to
run address before the C/C++ boot code is executed or is placed with single
allocation specifier (ex. "> MEMORY").
But I don't how to fix this. Is there something to change to the cmd file ? (I use the original file)
MEMORY
{
FLASH (RX) : origin = 0x00000000, length = 0x00010000
SRAM (RWX) : origin = 0x20000000, length = 0x00010000
}
/* Section allocation in memory */
SECTIONS
{
GROUP
{
.intvecs
.text
.const
.data
} load = FLASH, run = 0x20000000, LOAD_START(init_load), RUN_START(init_run), SIZE(init_size)
GROUP
{
.bss
.stack
} run = SRAM, RUN_START(bss_run), RUN_END(bss_end), SIZE(bss_size), RUN_END(__STACK_TOP)
}
