Memory Map on At91Samx256 in GDB

Development Boards MicroMod
1

Hello,

if i use the OpenOCD Feature to send the Memory-Map to my GDB the command “info mem” returns:

~“Using memory regions provided by the target.\n”

~“Num Enb Low Addr High Addr Attrs \n”

~“0 y \t0x00000000 0x00100000 rw nocache \n”

~“1 y \t0x00100000 0x00140000 flash blocksize 0x4000 nocache \n”

~“2 y \t0x00140000 0x100000000 rw nocache \n”

I use this standard cfg “openocd -f interface/olimex-jtag-tiny.cfg -f target/sam7x256.cfg”.

Where does OpenOCD get the MemoryMap from? I think this map is not correct because:

  1. region 0 could be flash before remap command, after it´s RAM!?

  2. region 1 seems to be ok, but what does the blocksize mean?

  3. region 2 is RAM, Abort and Internal Peripherals!? rw?

Could anyone please help me to understand where these values come from, and why.

For now i use the “gdb_memory_map disable” OpenOCD Command and with this the debugging gets nomore DataAborts…I just want to unterstand whats going on with this “auto memory map”…

Thank you!

2

The memory map is created from the flash config line, for example.

flash bank at91sam7 0 0 0 0 0 0 0 0 0 0 0 0 18432

In your case the values are probed from the actual target.

the only line of interest is the flash one - this helps gdb decide when to use hardware breakpoints and what addresses to program when a load cmd is given.

The blocksize is the smallest flash sector in the device.

This will be the size used when gdb tried to erase the target.

Cheers

Spen