Flash Security Operation

3.The CCIF and ACCERR flags are set if a command is active when the MCU enters stop mode.

NOTE

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.

WARNING

Active commands are immediately aborted when the MCU enters stop mode. Do not execute the STOP instruction during program and erase operations.

6.4.5Master 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.

6.5Flash 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.

NOTE

Enabling Flash security will disable BDM communications.

NOTE

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

Chapter 6. ColdFire Flash Module (CFM)

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Motorola MCF5281, MCF5282 user manual Flash Security Operation, Master Mode