nRF52 APPPROTECT

Question

Hi, 
 Is there a way on the nRF52 to clear the APPPROTECT bits once they have been set? 
 On the nRF51, it was still possible to erase the chip to clear the readback protection. However, on the nRF52, the APPPROTECT bits seem to fully disable the debugger. 
 Thanks, 
 Eric

David García Polo · Accepted Answer

The public documentation of the unprotection mechanism is missing, but you can either do: 
 
 Use nrfjprog.exe -f NRF52 --recover 
 Use nrfjprog.dll function recover() or use the pynrfjprog recover() 
 Manually, a) write 1 to register 0x4 of debug access port 1, b) read register 0x8 of debug access port until its value is 0, c) write 0 to register 0x4 of debug access port 1, d) write 1 to register 0x0 of debug access port 1, e) write 0 to register 0 of debug access port 1. 
 
 I understand that option 3 is the only option available if you do not use nrfjprog. What do you use?

nRF52 APPPROTECT

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