Nucleo-L496ZG-P Issue flashing board

[cbarb2747]

For the first week of having the board, I was able to load different programs with no problem. Somehow, it seems that I got the board into a bad state.  Now, most of the times when I try to flash a program to the board I get the infamous:

Waiting for debugger connection...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Debugger connected

Waiting for debugger connection...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Target is not responding, retrying...

Shutting down...

Exit.

Sometimes, I can get a program to flash if I, hit the reset button a bunch, unplug and plug back in the board, clean the workspace,

rebuild the workspace, then load the program. This is very annoying and frustrating when trying to

program and then debug a program. I have also tried different chords.
Any help would be greatly appreciated. I am not sure how this happened. Everything was run super smoothly at first with the board.

[Peter BENSCH]

Welcome @cbarb2747, to the community!

You have probably programmed something with an ultra-low power mode, so that the IDE can no longer access the target without the debugger option ‘Connect under Reset’.

Regards
/Peter

[cbarb2747]

Thank you for the warm welcome and the reply.  So I just need to go to the settings and check the debugger option 'Connect Under Reset'?  I am learning barre metal programming and manipulating the registers for my board and am writing some simple programs to work with uart and i2c.  It is weird cause I was programming some simple gpio programs with leds and push buttons last week and had no issue.  Is it just the programs I am writing now that are causing the low power mode or is there a way to get the board out of this state? 

[Peter BENSCH]

Well, there are several modes in which your STM32L496 can work, including the ultra-low power modes, in which access via SWD is only possible via hardware reset. If this has been set with the current programme, the STM32 will remain in this state until you programme it differently.

Nevertheless you can access the target by setting the following path (with STM32CubeIDE):

Run > Debug Configurations... > [make sure that your application on the left is selected] > tab Debugger > Reset behaviour: set Type = Connect under reset

Regards
/Peter