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3. The CCIF and ACCERR flags are set if a command is active when the MCU enters
stop mode.
The state of any longword(s) being programmed or any erase
pages/physical blocks being erased is not guaranteed if the
MCU enters stop mode with a command in progress.
Active commands are immediately aborted when the MCU
enters stop mode. Do not execute the STOP instruction during
program and erase operations.
6.4.5
Master Mode
If the MCU is booted in master mode with an external memory selected as the boot device,
the CFM will not respond to the first transfer request out of reset. This will allow the
external boot device to provide the reset vector and terminate the bus cycle.
6.5
Flash Security Operation
The CFM array provides security information to the integration module and the rest of the
MCU. A longword in the Flash configuration field stores this information. This longword
is read automatically after each reset and is stored in the CFMSEC register.
Enabling Flash security will disable BDM communications.
When Flash security is enabled, the chip will boot in single
chip mode regardless of the external reset configuration.
In user mode, security can be bypassed via a back door access scheme using an 8-byte long
key. Upon successful completion of the back door access sequence, the module output
signal and status bit indicating that the chip is secure are cleared.
The CFM may be unsecured via one of two methods:
1. Executing a back door access scheme.
2. Passing an erase verify check.
MOTOROLA
NOTE
WARNING
NOTE
NOTE
Chapter 6. ColdFire Flash Module (CFM)
Flash Security Operation
6-23
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