How to set a function in a certain address? - Electronic Circuits Projects Diagrams Free

alphadog · 11th February 2009, 08:04 PM

I have a port that when any of its pin causes an interrupt, it vectors the MCU to address 0x7B.
I would like to create a new file, and write inside it a function, and have the function's address to be 0x7B.
I'd mention that i write the code in C language, not in assembly language.

How can i do that?

Thanks!

dknguyen · 11th February 2009, 08:58 PM

At least for PICs, there is a preset function name of some sorts that is at that memory address and gets called whenever the interrupt is triggered. You just declare the function using that name and type out your routine and it just runs whenever the interrupt fires. Check your compiler user manual about interrupts.

alphadog · 11th February 2009, 09:11 PM

Thanks for the answer.
You suggest a nice way how to bypass the setting of a function in a ceratin address.
I'd still like to know how you do that, becuase i assume its possible.

By the way, i use the CC2430 MCU.

dknguyen · 11th February 2009, 09:14 PM

I don't know anything about that processor.

alphadog · 11th February 2009, 09:50 PM

Alirght,
I know that if i used assembly language, i could use the command ' DSEG AT 0x7B '
and their i would be calling my function that serves interrupts.
I just dont know how to write it in C language.

dknguyen · 11th February 2009, 10:10 PM

YOu can write sections of assembly in C you know.

I think you use asm{...} or something like that.

alphadog · 11th February 2009, 10:22 PM

Yes but the whole other code is written in C, so implementing single asm file in the code wouldn't be a good idea.

colin mac · 11th February 2009, 11:18 PM

You don't need asm. What compiler and have you read the manual.?

Papabravo · 12th February 2009, 08:13 AM

The IAR Compiler for the 8051 has an interrupt keyword that is used to bind a function to an interrupt vector.

Code:

interrupt [0x0023] using [SP_BANK] void SERIALISR(void)
{
...SERIALISR Code
}

It is common to declare an interrupt function as having no return value and taking no arguments. So 0x0023 is the absolute address of the serial port ISR inb all the 8051s you will ever see besides all the ones that you won't. The using qualifier selects one of 4 register banks to be used by the interrupt procedure.

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11th February 2009, 08:04 PM	#1
alphadog	How to set a function in a certain address? I have a port that when any of its pin causes an interrupt, it vectors the MCU to address 0x7B. I would like to create a new file, and write inside it a function, and have the function's address to be 0x7B. I'd mention that i write the code in C language, not in assembly language. How can i do that? Thanks!

11th February 2009, 08:58 PM	#2
dknguyen	At least for PICs, there is a preset function name of some sorts that is at that memory address and gets called whenever the interrupt is triggered. You just declare the function using that name and type out your routine and it just runs whenever the interrupt fires. Check your compiler user manual about interrupts. Last edited by dknguyen; 11th February 2009 at 08:58 PM.

11th February 2009, 09:11 PM	#3
alphadog	Thanks for the answer. You suggest a nice way how to bypass the setting of a function in a ceratin address. I'd still like to know how you do that, becuase i assume its possible. By the way, i use the CC2430 MCU.

11th February 2009, 09:14 PM	#4
dknguyen	I don't know anything about that processor.

11th February 2009, 09:50 PM	#5
alphadog	Alirght, I know that if i used assembly language, i could use the command ' DSEG AT 0x7B ' and their i would be calling my function that serves interrupts. I just dont know how to write it in C language.

11th February 2009, 10:10 PM	#6
dknguyen	YOu can write sections of assembly in C you know. I think you use asm{...} or something like that.

11th February 2009, 10:22 PM	#7
alphadog	Yes but the whole other code is written in C, so implementing single asm file in the code wouldn't be a good idea.

11th February 2009, 11:18 PM	#8
colin mac	You don't need asm. What compiler and have you read the manual.?

12th February 2009, 08:13 AM	#9
Papabravo	The IAR Compiler for the 8051 has an interrupt keyword that is used to bind a function to an interrupt vector. Code: interrupt [0x0023] using [SP_BANK] void SERIALISR(void) { ...SERIALISR Code } It is common to declare an interrupt function as having no return value and taking no arguments. So 0x0023 is the absolute address of the serial port ISR inb all the 8051s you will ever see besides all the ones that you won't. The using qualifier selects one of 4 register banks to be used by the interrupt procedure. __________________ We never have time to do it right; but we always have time to do it over.