> 1. Which script and config files (and makefile settings) are controlling
> flashing and debugging?
Eclise uses the Zylin Plugin to talk to a gdb-server via the gdb-client 
(arm-*-gdb). In your case it's the gdb-server from Segger. Did you 
configure TCP/IP port correctly (2331 for J-Link gdb-server IRC)?

For flashing the makefile might include calls to an external 
flash-programming software but this is not realy needed for debugging. 
Just an elf-file is needed.

If you can call a programming-software from Segger from the command line 
you can add this call to the makefile, in example in a programm target. 
But this is not related to debugging or Eclipse.

> 2. Is there tutorials/examples for the files?
I don't know if the J-Link gbd-server has a flash-programming interface. 
If yes, the gdb-command load can be used for flashing. There is no need 
for a special file.

> 3. Can I break something with wrong config files?
I don't think so.

> I'm already followed applicable parts of the following tutorials:
> http://developers.stf12.net/eclipse-demo
You are using the J-Link gdb-server instead of OpenOCD, but the basic 
concept is the same as shown in this tutorial.

> http://embeddedcraft.org/freearmtools2.html
This is not too helpful since Insight is used as debugging frontend, not 
the debugger in Eclipse.

> http://www.yagarto.de/howto.html
You may want to re-read http://www.yagarto.de/howto/yagarto2/index.html


Sorry, no real "fist hand" recommendations, maybe someone else can write 
a little bit more on this. I'm using another hardware-interface 
(FTDI2232-based), another gdb-server (OpenOCD) and another plugin 
("official" Eclipse/CDT gdb-hardware-debugging plugin).
You may also ask in Segger's support-forum or write an e-mail to the 
address mentioned in the imprint or yagarto.de

jera wrote:
>...
> Does that look like reasonable?
The monitor commands are J-Link gdb-server specific. List looks 
reasonable to me but as written, I'm using another gdb-server. Someone 
else needs to comment on this.

> How it is selected is the debugging performed from flash or RAM?
You already have "from Flash". For "from RAM" Link the application into 
addresses in the RAM's address-range (linker-script/setup)

At debugger-startup:
- set the Stack-pointer to first value in vector-table
- set PC to second value in vector-table-table
- make sure the NVIC-offset position is set to the start-address in RAM 
early (before an interrupt can occur).
The steps can be implemented as additional commands in you 
initialization list.

> In some gdb initialization examples there were commands for setting PLL.
> Is that needed?
Some targets start at a very slow coreclock (in example 32kHz). So the 
PLL gets initializes very early the achieve reasonable 
communication/transfer speeds.

> What clock frequency is selected without any commands?
Depends on target. Some targets offer external pins of non-volatile 
memory-sections to set this up. In your case: If /SRST is asserted and 
deasserted during "monitor reset" the clock will be the default clock 
after reset as mentioned see STM32 reference-guide.