SPRUJ53B April 2024 – September 2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1
On this device, OTP as well as normal Flash, are secure resources. Each zone has a dedicated OTP, whereas normal Flash sectors can be allocated to any zone based on the value programmed in the GRABSECTx location in OTP. Each zone has a 128-bit CSM passwords. Read and write accesses are not allowed to resources assigned to Z1 by code running from memory allocated to Z2 and conversely. Before programming any secure Flash sector, either unlock the zone to which that particular sector belongs using PMF or execute the Flash programming code from secure memory that belongs to the same zone. The same is the case for erasing any secure Flash sector. To program the security settings in OTP Flash, unlock the CSM of the respective zone. Unless the zone is unlocked, security settings in OTP Flash can not be updated. The OTP content cannot be erased.
A semaphore mechanism is provided to avoid the program/erase conflict between Z1 and Z2. A zone needs to grab this semaphore to successfully complete the erase/program operation on the secure Flash sectors allocated to that zone. A semaphore can be grabbed by a zone by writing the appropriate value in the SEM field of the FLSEM register. For further details of this field, see the register description.