Can't connect with arm-elf-gdb

Development Boards MicroMod
1

Hello!

I’m trying to connect to the Olimex’s SAM7-EX256 board using OpenOCD and ARM-USB-OCD but I’m having no luck. This is the configuration script (it’s the same that you can find in OpenOCD scripts page).

#daemon configuration
telnet_port 4444
gdb_port 3333 

#interface
interface ft2232
ft2232_device_desc "Olimex OpenOCD JTAG A"
ft2232_layout olimex-jtag
ft2232_vid_pid 0x15BA 0x0003
jtag_speed 0
jtag_nsrst_delay 200
jtag_ntrst_delay 200

#use combined on interfaces or targets that can't set TRST/SRST separately
reset_config srst_only srst_pulls_trst 

#jtag scan chain
#format L IRC IRCM IDCODE (Length, IR Capture, IR Capture Mask, IDCODE)
jtag_device 4 0x1 0xf 0xe 

#target configuration
daemon_startup reset 

#target <type> <startup mode>
#target arm7tdmi <endianness> <reset mode> <chainpos> <variant>
#target arm7tdmi little reset_init 0 arm7tdmi
target arm7tdmi little run_and_halt 0 arm7tdmi
#target arm7tdmi little reset_halt 0 arm7tdmi
target_script 0 reset at91sam7_ecr.script
#run_and_halt_time 0 30

# flash-options AT91
working_area 0 0x00200000 0x4000 nobackup
flash bank at91sam7 0 0 0 0 0


# Information: 
# erase command (telnet-interface) for complete flash:
# flash erase <num> 0 numlockbits-1 (can be seen from output of flash info 0)
# SAM7S64 with 16 lockbits and bank 0: flash erase 0 0 15
# set/clear NVM-Bits:
# at91sam7 gpnvm <num> <bit> <set|clear>
# disable locking from SAM-BA:
# flash protect 0 0 1 off



# For more information about the configuration files, take a look at:
# http://openfacts.berlios.de/index-en.phtml?title=Open+On-Chip+Debugger

I’m using arm-elf-gdb to connect as you can see:

D:\>arm-elf-gdb
GNU gdb 6.0
Copyright 2003 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
This GDB was configured as "--host=i686-pc-cygwin --target=arm-elf".
(gdb) target remote localhost:3333
Remote debugging using localhost:3333
Cannot access memory at address 0x20000000
0x000001f0 in ?? ()
(gdb)

My questions are:

Why does try to connect to 0x20000000?

What can I do to correct this?

The plan is to use this system to debug applications in RAM and Flash.

Thanks,

Luís M. Costa

2

Hello Luís,

as far as I can tell from the information you’ve pasted the arm-elf-gdb connected to the OpenOCD without problems.

(gdb) target remote localhost:3333

Remote debugging using localhost:3333

Cannot access memory at address 0x20000000

GDB tried to read from 0x20000000 which failed as expected, as there’s no memory at that address on the SAM7X as far as I can tell. It’s likely that GDB tried to trace the stack frames when there wasn’t one. This isn’t a problem.

0x000001f0 in ?? ()

The target was halted at address 0x1f0, and as you don’t have a symbol file loaded it can’t tell you what there is at that address.

(gdb)

GDB is waiting for your commands.

Regards,

Dominic