Boot Assist Module (BAM)
MPC5606S Microcontroller Reference Manual, Rev. 7
170 Freescale Semiconductor
Then the device executes this startup code. A user application should have a valid instruction at the reset
boot vector address.
If a valid RCHW is not found, the BAM code is executed. In this case BAM moves the MPC5606S into
static mode.
6.5.3.1 Boot and alternate boot
Some applications require an alternate boot sector so that the main boot can be erased and reprogrammed
in the field.
When an alternate boot is needed, the user can create two bootable sectors. The lowest sector is the main
boot sector, and the highest is the alternate boot sector. The alternate boot sector does not need to be
consecutive to the main boot sector.
This scheme ensures that there is always one active boot sector by erasing one of the boot sectors only:
• Sector is activated (that is, program a valid BOOT_ID instead of 0xFF as initially programmed).
• Sector is deactivated writing to 0 some of the bits BOOT-ID bit field (bit 1 and/or bit 3, and/or bit
4, and/or bit 6).
6.5.4 Boot through BAM
6.5.4.1 Executing BAM
Single-chip mode is managed by hardware and BAM does not participate.
BAM is executed only in the following two cases:
• Serial boot mode has been selected by FAB pin
• Hardware has not found a valid Boot-ID in any flash boot locations
If one of these conditions is true, the device fetches code at location 0xFFFF_C000 and BAM application
starts.
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