v1.0

Application settings

Enabling secure access port protection prevents the secure debugger from accessing the CPU and memories. This means that memory regions marked secure in the SPU and CPU while running secure code are inaccessible. Secure access port protection is enabled by writing the corresponding UICR register and issuing a system reset.

General access port protection can be enabled to prevent all debugger access to the CPU and memories. The protection is enabled by writing the corresponding UICR register and issuing a system reset.

After enabling access port protection, only a full erase through the control access port (CTRL-AP) allows debugging or flash access. This can be done by performing a CTRL-AP erase all.

Erase protection can be enabled to prevent a CTRL-AP erase all from lifting the access port protection. When this feature is enabled, a debugger must first authenticate with the firmware through the CTRL-AP MAILBOX and ERASEPROTECT.DISABLE registers before a CTRL-AP erase all is possible.

For more information, see nRF9160 CTRL-AP - Control access port in nRF9160 Product Specification.