A *working* demo of Monitor Mode Debug (MMD) on SDK 15, please?

[awneil]

The zipped project attached to this blog doesn't say what SDK version it should work with - but it certainly doesn't work with v15.

https://devzone.nordicsemi.com/b/blog/posts/segger-embedded-studio-part-2-monitor-mode-debuggi

Having fixed the Include Paths (whose stupid idea was it to make them absolute?!), I can get the source to compile with SDK v15 - but the link fails:

cannot move location counter backwards (from fffffffffffffc00 to 0000000000000000)

The point at which this is flagged is:

__stack_load_start__ = __SRAM_segment_end__ - 1024;
.stack __SRAM_segment_end__ - 1024 (NOLOAD) : AT(__SRAM_segment_end__ - 1024)
{
__stack_start__ = .;
*(.stack .stack.*)
. = ALIGN(MAX(__stack_start__ + __STACKSIZE__ , .), 8);
}

What is wrong, and how to I fix it?

[haakonsh]

I've made a new tutorial for SDK14.2, and working on SDK15. 

See https://github.com/NordicPlayground/j-link-monitoring-mode-debugging and the SDK14.2 branch.

[awneil]

Thanks.

Could you clarify the question (above) about SetMonModeVTableAddr ?

(to be pedantic, note that it's usually called "monitor mode" - rather than "monitoring mode")

EDIT

The SES tutorial also doesn't mention the  mon exec SetMonModeDebug=1 command

[haakonsh]

I'm not familiar with GDB, but SetMonModeDebug=1 should be place in the projects j-link setting file. The j-link will read this file at the beginning of each j-link dll session and use those settings. I'm assuming that "mon exec" is some sort of keyword to include the following keywords to the j-link settings file. 

[awneil]

haakonsh said:

I'm not familiar with GDB

Neither am I!

I'm not asking about GDB - just SES.

[haakonsh]

Aah, I forgot to document it.

1. Open up the example project from the SDK14.2 branch.
2. Right-click 'Project ble_app_blinky...' and choose 'Edit Options'.
3. Select 'Debug' from the drop-down menu. (Common, Debug, Release).
4. Go to Debug -> J-Link -> Additional J-Link Options. Double click to view or edit.

[awneil]

You're missing the point!

The question was whether the option(s) are necessary - not how to specify them!

And, in the case of the SetMonModeVTableAddr option, what value, exactly, has to be specified?

[haakonsh]

The application's vector table is at the start of the application's starting address in flash. In a SES project you'll find it in:
Option for project -> Common -> Linker -> Section Placement Macros -> FLASH_START. 

[awneil]

and is the SetMonModeVTableAddr option actually necessary ?

[haakonsh]

Yes. 
When the J-link driver is configured for MMD mode it will convert a regular 'Halt CPU' command into an 'execute MMD ISR'. In order to execute the Monitor Mode ISR the J-link driver needs to know the vector table. 

This is described in the Segger J-Link/J-Trace User Guide chapter 9. Monitor Mode Debugging. 

[awneil]

It would be helpful if Your tutorial explained this!

As noted, the original missed it: https://devzone.nordicsemi.com/b/blog/posts/segger-embedded-studio-part-2-monitor-mode-debuggi

And the other tutorial included it, but with no clear explanation: https://devzone.nordicsemi.com/b/blog/posts/monitor-mode-debugging-with-j-link-and-gdbeclipse

Hence me banging on trying to get you to clarify it.

[haakonsh]

I appreciate the input, I've raised a couple of 'Issues' in the new repo and will get to it eventually. 
Don't hesitate to ask more :)

[awneil]

haakonsh said:

In order to execute the Monitor Mode ISR the J-link driver needs to know the vector table. 

Yes, that makes sense.

So the question is: why was this command not in the original article?

https://devzone.nordicsemi.com/b/blog/posts/segger-embedded-studio-part-2-monitor-mode-debuggi 

ie, how does that one get away without it?