Chapter 33 Boot Assist Module (BAM)
MPC5602P Microcontroller Reference Manual, Rev. 4
Freescale Semiconductor
823
33.5.5.2
BAM software flow
illustrates the BAM logic flow.
Figure 33-4. BAM logic flow
The first action is to save the initial device configuration. In this way is possible to restore the initial
configuration after downloading the new code but before executing it. This allows the new code being
executed as the device was just coming out of reset.
The BMODE and ABD fields of SSCM_STATUS register (see
Section 10.2.2.1, “System Status register
) indicate which boot has to be executed (see
If the BMODE field shows either a single chip value (011) or a reserved value, the boot mode is not
considered valid and the BAM pushes the device into static mode.
In all other cases the code of the relative boot is called. Data is downloaded and saved into proper SRAM
location.
BAM entry
0xFFFF_C000
Save default
configuration
Check
boot mode
The selected boot mode is verified
by reading the SSCM_STATUS register
(bits BMODE and ABD)
Boot mode
valid?
Download new
and save to
SRAM
Restore
default
configuration
Restore
default
configuration
NO
YES
STATIC mode
Execute
new code