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SNVS tamper reset

Question asked by Stephan van Kampen on Jan 15, 2020
Latest reply on Jan 16, 2020 by Yuri Muhin

Hi all,


I try to create an example application to display the tamper status and a button to reinitialize the tamper.


The first part is working perfectly. On active tamper the snvs switches to softfail state and the correct tamper pins has fired.

The second part does not work:

Step 1: make use the active tamper pair / mesh is closed --> Check

Step 2: Try to change internal SSM state from softfail to non-secure by writing bit SSM_ST bit in HPCOMR --> HPSR register does not reflect the state I expected, HPSR SSM status is still Softfail.

Step 3: read and write LPSR / LPTDSR registers to clear tamper warning --> does not work, tamper value keeps 1.


I have already checked NPSWA_EN bit  == 1 and checked the HPLR and LPLR registers for any locks which prohibts to change the SSM state from softfail to non-secure.


Does some has an idea to reset snvs tamper status for debug purposes?