Q:

I accidentaly disabled the debug pins in the application code on my EFM32 and now I am unable to access the EFM32 device through the debug interface on my development kit. Is there any way to gain access again? Is there a mass erase function or similar?

A:

Yes, the energyAware Commander tool in Simplicity Studio includes an "Unlock debug access" feature which halts the EFM32 before it starts running code and erases the flash image. This feature requires you to use one of the Energy Micro EFM32 starter or development kits. 

Steps:

1) Install Simplicity Studio from http://www.energymicro.com/software/simplicity-studio

2) Go to Start-> Programs->Energy Micro and start  Simplicity Studio

3) Make sure the energyAware Commander package is installed in Simplicity Studio. Check this article for help on updating Simplicity Studio.

4) Connect the development kit or starter kit to your PC and power it on

5) Start energyAware Commander in Simplicity Studio and click "Connect" on the upper left corner of the energyAware Commander.

6) Make sure that "Debug Mode" in Board Information is set to correctly. If it is the EFM32 on the kit itself you want to unlock, then set it to "MCU".If you are using using the kit to unlock a device on a separate PCB, then set this mode to "OUT" To debug an external target you also need to connect the debug and reset lines as described in application note AN0002.

7) In eA Commander, Go to "Flash" on the left side section

8) Click on "Unlock debug access"

9) Press OK, when warned that this will erase all contents of the EFM32.

10) Wait at least 10 seconds while the unlock is ongoing before pressing OK in the second box.

 The device should now be unlocked and erased and you should be able to gain access through the debug interface again.