APPROTECT and DAP

Question

Hi, 
 I have a JLink script which sets APPROTECT in the UICR to enable readback protection and disable the debug interface. 
 For development purposes, I would like to be able to clear these. The process seems to be to write certain values to the CTRL-AP registers. However, I cannot find the base memory address for the DAP or CTRL-AP registers anywhere in the nRF52832 1. 0 data sheet. Does anyone know the base address for this register set? If not part of the memory space register, how would I command JLink to write data to the appropriate place to erase the chip after read back protection has been enabled? 
 Thanks, 
 Eric

Eric Stutzenberger · Accepted Answer

I figured out the solution: 
 You cannot ask JLink Commander to connect to the device after APPROTECT is set. This causes commander to switch to some state where SWDWriteDP/SWDReadDP always fails with an error. I don't fully understand what state the connect command causes in JLink Commander. Instead, after starting JLInk Commander send only the SWDSelect command. 
 
 
 Start JLink Commander 
 
 
 SWDSelect -> Selects SWD Interface 
 
 
 SWDWriteDP 1 0x50000000 -> Enable power (as suggested by Segger response) 
 
 
 SWDWriteDP 2 0x01000000 -> Seleect CTRL-AP Bank 0 
 
 
 SWDWriteAP 1 0x00000001 -> Full Chip Erase 
 
 
 SWDReadAP 2 -> Repeat until 0 
 
 
 SWDReadAP 3 -> Two reads show 0x00000001 meaning protection cleared 
 
 
 Thanks for the help.

APPROTECT and DAP

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