Chapter 33 Boot Assist Module (BAM)
MPC5602P Microcontroller Reference Manual, Rev. 4
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Freescale Semiconductor
If a valid RCHW is not found, the BAM code is executed. In this case BAM moves the MPC5602P into
static mode.
33.5.4.1
Boot and alternate boot
Some applications require an alternate boot sector in the flash so that the main sector in flash can be erased
and reprogrammed in the field.
When an alternate boot is needed, the user can create two bootable sectors. The low sector is the main boot
sector and the high sector is the alternate boot sector. The alternate boot sector does not need to be
consecutive to the main boot sector.
This ensures that even if one boot sector is erased still there will always be another active boot sector:
•
Sector shall be activated (i.e., program a valid BOOT_ID instead of 0xFF as initially programmed).
•
Sector shall be deactivated writing to 0 some of the bits BOOT_ID bit field (bit1 and/or bit3, and/or
bit4, and/or bit6).
33.5.5
Boot through BAM
33.5.5.1
Executing BAM
Single chip boot mode is managed by hardware and BAM does not participate in it.
BAM is executed only on these two following 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.