Question about #build (reset=0X200, interrupt=0X208)

[Hans Wedemeyer]

I'm trying to move the application reset vector and interrupt vectors out of the boot block.

#build(reset=0x200,interrupt=0X208)
#org 0X0, 0X1FF {} // don't use boot block

This compiles, but the interrupts are not working !

I just called CCS help and was told to use jump_to_isr() !
The latest help file has very little information on how to use this here is all it says: (with my comments:

int_global // what is this and where does it go ?

void global_isr(void) // does this replace the CCS generated isr handling ?
{
jump_to_isr(isr_address); // do I need to add a statement for every ISR ?
}

Lastly how do I get the address of the ISR ? is this done dynamically or at compile time ?

[PCM programmer]

There's an example of its use in Ex_Bootloader.c.
It's in this location:

[Hans Wedemeyer]

The example is not clear about what happens to the original isr dispatcher.

Does this new isr() replace the isr dispatcher ?

The value LOADER_END+5 seems to be specific to the ex_loader example.
But what address do I need to use ?

Is it 00208: GOTO 02CE // the isr dispatcher (from lst file)

This is not clear at all.

#int_global
void isr(void)
{
jump_to_isr(LOADER_END+5*(getenv("BITS_PER_INSTRUCTION")/8));
}

I'm lost ...

[Ttelmah]

The compiler generates the normal dispatcher at the 0x208 address (this is what the 'build' statement tells it to do). You need to jump the physical interrupt, to this address, with the routine placed in the bootloader code.

Best Wishes

[Hans Wedemeyer]

[Ttelmah]

It doesn't.
To use interrupts, the bootloader, _must_ vector the interrupt jump, 'into' the real code. The following assumes only low priority interrupts are being used - otherwise two vectors come into play.
If you generate a program, with the build statement given, the compiler generates:
0x200 GOTO main_program_entry
0x208 The ISR handler

The hardware still generates a call to address 8 (this cannot be changed), so the bootloader needs to itself contain an 'int_global' handler, which just comprises a jump to address 0x208.
The bootloader code, must provide this relocation.

Best Wishes

[Hans Wedemeyer]

[Ttelmah]

Only if you are using both.
If interrupt priority is disabled, the 08 address is used.

Best Wishes

[Hans Wedemeyer]

[Guest]

Yes.
The 'jump_to_isr' instruction will automatically handle both. This is the difference between using this, and a manual 'goto'.
What else are you going to put in the space between the jumps?. There is not enough space for any useable code, and nop is safe.
It doesn't "retfie back to the NOP's". When 'retfie' is executed at the end f the handler in the main code, the handler returns to where the interrupt occured. The address is on the stack.
The NOP's should never be executed.

Best Wishes

[Hans Wedemeyer]