Flash Bootloader (FBL). The FBL is a PBL with the SBL pre-loaded to flash.
In a PBL+SBL solution the PBL downloads the SBL to RAM. The SBL is started in RAM and then down- loads and ﬂashes the application.
The ﬂash bootloader (FBL) is actually a PBL+SBL. This means that the FBL will have a larger ROM footprint but will not have to download the SBL, since it’s already there. When the bootloader needs to program, the entire SBL is copied from ROM to RAM and executes from RAM.
Features of the bootloader
The bootloader is responsible for a number of things such as verifying the application image, transfer application code from external source into internal memory.
It can be build as:
ISO15765 transport protocol over can
Example for MPC5606B (Diab, VLE, "-XO -Xsize-opt -g3")
PBL - 7.7 KByte Flash
SBL - 9.2 KByte RAM
FBL - 7.7 + 9.2 = ~17 KByte Flash
Supported addressing formats
Normal ﬁxed addressing
Message area for communication with application.
Additional features that must be implemented by customer:
Self update of PBL/FBL Normally done by the application not the bootloader.