Hi Yann,

the most used way:

insert in your boot EPROM the following assembler routine:

org 3
jmp 4003h
org 0bh
jmp 400bh
org 13h
jmp 4013h
...

Then write your application in the same way as starting at address 0000h.
On compiling you must set the directive: INTVECTOR(0x4000)
This tells the compiler, that the interrupts are redirected to 0x4003, 0x400b, ...
The startup.a51 must also be modified:
CSEG AT 4000h
Finally the linker must get the directive: CO (4000h)


To use interrupts also in the boot program, there are several ways.
E.g. you can reserve a single bit and on any interrupt this bit was tested and 2 different jumps can be done depending from the bit.
E.g. to 4003h, 400bh, ... for the application or 0083h, 008bh, ... for the boot program:

org 3
jnb 0, 0083h
jmp 4003h
org 0bh
jnb 0, 008bh
jmp 400bh
...

The more complicated way: Your application runs in a RAM and the boot program write a jump to its own interrupt routine into this RAM.


Peter