8.5.3.1 Exceptions

Not all bits are coded and thus the security access of some peripherals may not be controlled by the TZPM. These peripherals include:

• Always Secure IDs
• TrustZone Controller (TZC) protected IDs
• Secure DMA
• OTP Controller (OTPC)

In some cases, the bit index controlling the access permission differs from the peripheral ID. This is the case when several peripherals share a common security bit. These peripherals include:

• DDR3PHY and UDDRC permissions are controlled by the bit index ID_DDR3PHY

Some peripheral IDs do not correspond to a peripheral user interface but only to an interrupt (for example, ID_AES_SINT). In this case, the security bit is read-only and equals zero except when the associated interrupt targets only the Non-secure world. Note that the value of the security bit must be ignored for interrupt-only IDs.

Some peripheral IDs are not assigned to any functionality. The corresponding security bit is 0 and is read-only.

ID_TZAESB_NS is the only programmable-secure peripheral with value ‘1’ (not secure) after reset.

ID_UHPHS is the only programmable-secure peripheral for which the user interface security is controlled by the AHB matrix (MATRIX). The security bit only controls the security of USB host ports.