To use J-Link debugger

Make sure you have J-Link software version 8.12 or newer.
Select the
Debug
tab in the Options for Target dialog, select
J-LINK / J-TRACE Cortex
as debug adapter, and click
Settings
:
If you see the following message, click
OK
in the Device selection message box:
Select the appropriate device in the Target device settings and click
OK
.
Go to the
Debug
tab in Target Driver Setup dialog and select:
- set
  Port
  to "SW"
- set
  Max Clock
  to "1 MHz"
- set
  Connect
  to "Normal"
- set
  Reset
  to "Normal"
- enable
  Reset after Connect
  option
Select the
Flash Download
tab in Target Driver Setup dialog and select
Reset and Run
option after download if needed: