Hello everyone,
I'm currently working on a bootloader (written in C) for a
MSP430F168-device. The bootloader should be placed in the two uppermost
segments of the flash memory (where also the interrupt vector table is
located). As the values stored in this table can therefore no longer be
changed, they should simply point to another "table" in a segment that
is not occupied by the BSL and can therefore be changed by the
bootloader.
I'm using Eclipse together with MSPGCC4 on Ubuntu 10.04.
My first approach to change the IVT was to add an assembler-file to my
project, containing the new values for this segment (.vectors is the
segment the IVT is stored in):
.section .vectors
InterruptVectors:
.word 0xFBE0
.word 0xFBE2
.word 0xFBE4
.word 0xFBE6
.word 0xFBE8
.word 0xFBEA
.word 0xFBEC
.word 0xFBEE
.word 0xFBF0
.word 0xFBF2
.word 0xFBF4
.word 0xFBF6
.word 0xFBF8
.word 0xFBFA
.word 0xFBFC
.word 0xFBFE
|
To make this have effect, I deactivated the use of the standard
startup-files by passing the -nostartfiles argument to the
compiler/linker.
When I look in the contents of the IVT by using
msp430-objdump -Dj .vectors BSL.elf |
I get the following (looks OK for me):
BSL.elf: file format elf32-msp430
Disassembly of section .vectors:
0000ffe0 <InterruptVectors>:
ffe0: e0 fb interrupt service routine at 0xfbe0
ffe2: e2 fb interrupt service routine at 0xfbe2
ffe4: e4 fb interrupt service routine at 0xfbe4
ffe6: e6 fb interrupt service routine at 0xfbe6
ffe8: e8 fb interrupt service routine at 0xfbe8
ffea: ea fb interrupt service routine at 0xfbea
ffec: ec fb interrupt service routine at 0xfbec
ffee: ee fb interrupt service routine at 0xfbee
fff0: f0 fb interrupt service routine at 0xfbf0
fff2: f2 fb interrupt service routine at 0xfbf2
fff4: f4 fb interrupt service routine at 0xfbf4
fff6: f6 fb interrupt service routine at 0xfbf6
fff8: f8 fb interrupt service routine at 0xfbf8
fffa: fa fb interrupt service routine at 0xfbfa
fffc: fc fb interrupt service routine at 0xfbfc
fffe: fe fb interrupt service routine at 0xfbfe
|
But when I now convert the created *.elf-file to *.hex for flashing
using
msp430-objcopy -O ihex -j .vectors BSL.elf out.hex |
(this should just put the contents of the IVT in the hex-file), I get
:0400000300004000B9
:00000001FF
|
For me, it looks like the IVT doesn't get copied to the hex-file. Is
this right?
Do you know any other approach how to change the IVT to support my
problem?
Best regards,
ikarus177
EDIT: I just tried to add the "a" attribute to the .section directive in
my assembler file. Now the IVT contents are also visible in the
hex-file:
:10FFE000E0FBE2FBE4FBE6FBE8FBEAFBECFBEEFB01
:10FFF000F0FBF2FBF4FBF6FBF8FBFAFBFCFB0090DA
:040000030000900069
:00000001FF
|
Can anybody explain this?
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