About S12 interrupt routine

There are two main ways to program interrupts for the MC9SDG128B:
      The first is to use the symbol "TRAP_PROC". TRAP_PROC tells the compiler that the following function is an interrupt service routine. The compiler will end this function with a special interrupt return instruction (for most processors, this is usually the RTI instruction).

     The second is to use the "interrupt" keyword. The "interrupt" keyword is a non-standard ANSI-C keyword, so it is not supported by all ANSI-C compiler vendors. Similarly, the usage of the "interrupt" keyword may change for different compilers. The "interrupt" keyword also prompts the compiler that the following function is an interrupt service routine.

     Once the interrupt service function is written, you must associate the interrupt service routine with the interrupt vector table. This is done by initializing the interrupt vector table. You can initialize the interrupt vector table in two ways:
     The first is in the PRM file, using the "VECTOR ADDRESS" or "VECTOR" command. The connector provides two commands to initialize the interrupt vector table: VECTOR ADDRESS or VECTOR. You use the VECTOR ADDRESS command to write the address of the interrupt service routine into the interrupt vector table.

    The second is to use the "interrupt" keyword. When you write an interrupt service routine, you can directly associate the interrupt service routine with a specific interrupt number in the ANSI-C source file.

    The following is the 16-bit free timer overflow interrupt handler for MC9SDG128B that I wrote, which has been debugged:
#include /* common defines and macros */
#include /* derivative information */
#pragma LINK_INFO DERIVATIVE "mc9s12dg128b"

int intcount = 0;

void timer_init(void)

{

TSCR2_PR0 = 1; //prescale factor is 128

TSCR2_PR1 = 1;

TSCR2_PR2 = 1;

TSCR2_TOI = 1; //overflow enable

TFLG2_TOF = 1;

TSCR1_TEN = 1; //timer enable
}

#pragma CODE_SEG NON_BANKED
interrupt 16 void timer_interrupt_handle(void)
{

intcount++;

TFLG2_TOF = 1; //clear interrupt flag
};
#pragma CODE_SEG DEFAULT

void main(void)
{

EnableInterrupts;

timer_init();

for(;;) {}
}

The following is an interrupt service routine written using the TRAP_PROC symbol:
#include /* common defines and macros */
#include /* derivative information */
#pragma LINK_INFO DERIVATIVE "mc9s12dg128b"
int intcount = 0;
void timer_init(void)
{

TSCR2_PR0 = 1; //prescale factor is 128

TSCR2_PR1 = 1;

TSCR2_PR2 = 1;

TSCR2_TOI = 1; //overflow enable

TFLG2_TOF = 1;

TSCR1_TEN = 1; //timer enable
}

#pragma CODE_SEG NON_BANKED
#pragma TRAP_PROC
void timer_interrupt_handle(void)
{

intcount++;

TFLG2_TOF = 1;
};
#pragma CODE_SEG DEFAULT

void main(void)
{

EnableInterrupts;

timer_init();

for(;;) {}
}

After the interrupt service program is written, you need to add the following sentence in the .prm file:
VECTOR 16 timer_interrupt_handle
so that the interrupt service program is associated with the corresponding interrupt number. This program has also been debugged.

The interrupt service routine must be located in the non-banked area. You can use "#pragma CODE_SEG NON_BANKED" to locate the interrupt routine in the non-banked area. At the same time, you must ensure that "sectionNON_BANKED" does not appear in the .prm file. At the end of the interrupt service routine, you need to add "#pragma CODE_SEG DEFAULT", otherwise, the following functions will also be located in the "non-banked" area.

So our interrupt service routine must be surrounded by "#pragma CODE_SEG NON_BANKED" and "#pragma CODE_SEG DEFAULT".