Boot Assist Module (BAM)
MPC5566 Microcontroller Reference Manual, Rev. 2
16-2 Freescale Semiconductor
16.1.2 Features
The BAM program provides the following features:
• Initial e200z6 core MMU setup with minimum address translation for all internal MCU resources
and external memory address space
• Locate and detect application boot code
• Automatic switch to serial boot mode if internal or external flash is not initialized or invalid
• Programmable 64-bit password protection for serial boot mode
• Boot application code from:
— Internal flash module
— external memory without arbitration
— external memory with arbitration
• Serial boot loads the application boot code from a FlexCAN or eSCI bus into internal SRAM
• Censorship protection for internal flash module
• Enable the e200z6 core watchdog timer
• Configurable memory map for use with the classic PowerPC Book E code or Freescale VLE code
• Configurable external data bus for 16- or 32-bit wide (416 and 496 PBGA packages only)
16.1.3 Modes of Operation
16.1.3.1 Normal Mode
In normal operation, the BAM responds to all read requests within its address space. The BAM program
is executed following the negation of reset.
16.1.3.2 Debug Mode
The BAM program is not executed when the MCU comes out of reset in OnCE debug mode. Use the
development tool to configure and initialize the MCU before accessing the MCU resources.
16.1.3.3 Internal Boot Mode
Use internal boot mode to boot from internal flash memory. Configuration information, initialization, and
boot code are kept in internal flash. The BAM program must complete the boot process before application
code can enable the external bus interface.
16.1.3.4 External Boot Modes
Use external boot mode when the boot code and configuration information are located in external memory
that is connected to the EBI. Enable bus arbitration for multiprocessor systems to allow a boot option. Do
not select external boot mode for devices without an external bus.
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