Freescale Semiconductor 802.15.4 - Manual (Page 40)

5-4 Embedded Bootloader Reference Manual, Rev 0.0 Freescale Semiconductor
NOTE
This file can also be used with the MC908HCS08GT60 MCU.
5.3.3 Crt0.c and Crt.h
These files contain the basic initialization code (basic system clock, memory and stack setup). The normal
basic init file(s) (like the start08.c from Metrowerks) is not needed when the Embedded Bootloader is
embedded.
In an 802.15.4/Zigbee application with Embedded Bootloader, these files only contain the _startupdata
structure. The Embedded Bootloader handles all the basic initialization (memory and stack setup) of the
application
. That is, the application’s main() function will be the first item called (entry point).
NOTE
Do not include basic initialization (memory and stack setup) when
building an application with the Embedded Bootloader. Place any
necessary initialization function calls in the main() function. Whatever,
the initialization function or only the _startupdata structure is included is
controlled by compiler #defines. See
Section 5.2.1, Compiler Defines
Application for more information.