9.4.10.3 IRT Partition

A designated portion of the user program memory may be used for the IRT partitions. IRT partitions are specified using Flash protection regions (refer to section Flash Protection Regions). One or more permanent IRT regions may be created for firmware, data, and cryptographic keys. Once IRT is enabled, IRT regions are only accessible during IRT execution, except for debug access when authorized by the IRT firmware. An IRT region may have write permissions disabled, making it immutable (generally for firmware) or have write permissions enabled (generally for configuration data and keys), allowing it to be updated.

Permission to access the IRT partition is indicated by the partition lock PLCK (IRTCTRL[4]) bit. Partition access is allowed (PLCK bit = ‘0’) when IRT is disabled, during IRT execution, and for debug access when the DBG (IRTCTRL[1]) bit is set. Otherwise, partition access is disabled (PLCK bit = ‘1’).