Security Interactions With Other Modules; Security Interactions With Debug - NXP Semiconductors freescale KV4 Series Reference Manual

Security Interactions with other Modules

8.3 Security Interactions with other Modules
The flash security settings are used by the SoC to determine what resources are available.
The following sections describe the interactions between modules and the flash security
settings or the impact that the flash security has on non-flash modules.

8.3.1 Security Interactions with Debug

When flash security is active the JTAG port cannot access the memory resources of the
MCU. Boundary scan chain operations work, but debugging capabilities are disabled so
that the debug port cannot read flash contents.
Although most debug functions are disabled, the debugger can write to the Flash Mass
Erase in Progress bit in the MDM-AP Control register to trigger a mass erase (Erase All
Blocks) command. A mass erase via the debugger is allowed even when some memory
locations are protected.
When mass erase is disabled, mass erase via the debugger is blocked.
KV4x Reference Manual, Rev. 2, 02/2015
Preliminary
116 Freescale Semiconductor, Inc.