Debugging/Running program in internal Flash.

[Claude Sylvain]

Hello,

I finally get the M52235 MCU internal FLASH programmed, using Flash 
Programmer tool.

Before programming the FLASH, I checked that the program was running 
well in the M52235 MCU internal SRAM.

I compiled again the same program using "m52235evb-rom.ld" instead of
"m52235evb-ram.ld" as the linker script file.  This is the only
change I made to the make file.

I called GDB using the same command sequence, except for the "load"
command that is no more necessary (I think).

 From that point, the program fail to start, and GDB display the following
message:


				   ----------

..
m68k-elf-sprite:Opening P&E USBMultilink port 1 (USB1 : USB-ML-CF Rev 
C (PE60123
45))
m68k-elf-sprite:Target reset
0x00000000 in __interrupt_vector ()
Breakpoint 1 at 0x512: file ./src/main.c, line 172.
Note: automatically using hardware breakpoints for read-only addresses.
Program received signal SIGTRAP, Trace/breakpoint trap.
0x00000004 in __interrupt_vector ()
(gdb)

				   ----------

Later, I unplugged the USB Multilink from the target, and try to start it
without the debugger by doing a POR (Power On Reset), without success.

Since the program is running well in internal SRAM, it seems to me that
something is wrong in the startup code.

Furthermore ...

Using the disassemble command of GDB, I take a look at the reset 
entry point (defined as __reset) and found something that looks like 
an endless loop.  See the GDB output below:


				   ----------

(gdb) disassemble 0xcf0
Dump of assembler code for function __reset:
0x00000cf0 <__reset+0>: linkw %fp,#0
0x00000cf4 <__reset+4>: halt
0x00000cf6 <__reset+6>: halt
0x00000cf8 <__reset+8>: bras 0xcf4 <__reset+4>
End of assembler dump.
(gdb)

				   ----------

Am I missing something, or there is really something wrong in the 
startup code ?


Claude Sylvain
Electro-Technica inc.