Configuring an LPC43xx debug connection to use SWD

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Configuring an LPC43xx debug connection to use SWD

Senior Contributor I

NOTE : In LPCXpresso IDE v7.8.0 and later, when you first debug a project, you will be given the option to select SWD (enabling the use of SWO Trace) or JTAG (to support multicore debugging). This typically avoids the need to modify the launch configuration to swap to SWD. However if you initially selected JTAG and later want to swap to debugging over SWD, then the method below can be used.


In order to support multi-core debugging, when making debug connections to LPC43xx parts, LPCXpresso IDE will default to using the JTAG protocol rather than SWD (which is used by default for connections to other Cortex-M based MCUs).

Generally, the use of JTAG rather than SWD is not a problem. But in some circumstances, you may wish to change your LPC43xx debug configuration to use SWD. For example:

  • SWO Trace functionality is only available when connecting to the target MCU using SWD. If you try to start SWO Trace whilst connected over JTAG, you will see an error message.
  • Typically, debug connections made over SWD may be slighter faster than JTAG ones. This might be useful, for example, if programming very large images to SPIFI flash.

Switching to use SWD

Select your project in the Project Explorer view and use right click to display the context sensitive menu.Now select the Launch Configuration entry:


If you have previously debugged the selected project, then select "Edit current...".If you have not previously debugged the selected project, then select "Create and edit new..."You will then see a new dialog box pop up...


Ensure that the required project/build configuration is selected in the left hand column...

Then on the right hand side of the dialog, select the Debugger tab and then the Target configuration sub-tab (as shown in the above screenshot).

Then scroll to the bottom of the sub-tab, and change the "Debug options template" from the default "NXP LPC43xx (JTAG)" to "NXP LPC43xx (SWD)":


You can then click on the Debug button to save the change and start a new debug session using an SWD connection.

Note: You will need to repeat this for each project that you wish to debug using SWD, and also for each build configuration

For more general info on launch configurations, please see:

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