Modify System init File

The system initialization file is usually located in your project'sProject_Settings > Startup_Code folder and named kinetis_sysinit.c. You can modify this file by following step.

Note: Refer to kinetis_sysinit.c from the newly created GCC project, for all the code that is added here.
  1. Add weak definitions of handlers point to UNASSIGNED_ISR.
    Figure 1. Add Weak Definition
    Add Weak Definition
  2. Define external variable _estack.
    Figure 2. Define External Variable
    Define External Variable
  3. Modify interrupt vector table.
    Figure 3. Interrupt Vector Table - Before
    Interrupt Vector Table - Before
    Figure 4. Interrupt Vector Table - After
    Interrupt Vector Table - After
  4. Provide Default interrupt handler. 
    void Default_Handler()

{

  __asm("bkpt");

}
  5. Remove the following pragmas to have clean build with no warnings.

    #pragma define_section vectortable ".vectortable" ".vectortable" ".vectortable" far_abs R

    and

    #pragma overload void __init_hardware();