Re: [avr-gcc-list] Problem with interrupt handler?

[Lai Kang Tin]

Hi,

You didn't initialize the timer, and enable the CPU interrupt in
main function before the for loop.

Kang Tin LAI

On Fri, 19 Oct 2001, Chris Baugher wrote:

> 
> Hi everyone,
> 
> I recently decided to try building some projects using the AVR chips and
> have been trying to get some simple test code to run on an at90s2313. I'm
> using avr-gcc 3.0.1 and binutils 2.11.2. The problem comes when I try to
> compile a program that has an interrupt routine declared. When I try to
> run the code on the chip I get all kinds of eratic behaviour, meaning it
> doesn't do what it's supposed to.
> So after poking around here is what I think.
> 
> This is the program I'm trying to run:
> 
> 
> /* START */
> 
> #include <io.h>
> #include <interrupt.h>
> #include <sig-avr.h>
> #include <timer.h>
> 
> static unsigned char ix=0;
> 
> SIGNAL(SIG_OVERFLOW0)
> {
>       ++ix;
> }
> 
> void main(void)
> {     
>       outp(0xFF,DDRB);        /* set port B for output mode */
>       
>       outp(0xFF,DDRD);
>       
>       for(;;) {
>               outp(ix,PORTD);
>       }
> }
> /* END */
> 
> 
> NOTICE!! Interrupts are never enabled so the ISR should never execute, but
> I think it does! Below is the list file generated by the assembler. It
> sure looks to me like the ISR is the very first thing executed.
> 
> 
> 
> GAS LISTING dro.s                     page 1
> 
> 
>    1                          .file   "dro.c"
>    2                          .arch at90s2313
>    3                  __SREG__ = 0x3f
>    4                  __SP_H__ = 0x3e
>    5                  __SP_L__ = 0x3d
>    6                  __tmp_reg__ = 0
>    7                  __zero_reg__ = 1
>    8                  _PC_ = 2
>    9                          .data
>   10                          .type   ix,@object
>   11                          .size   ix,1
>   12                  ix:
>   13 0000 00                  .byte 0
>   14                          .text
>   15                  .global _overflow0_
>   16                          .type   _overflow0_,@function
>   17                  _overflow0_:
>   18                  /* prologue: frame size=0 */
>   19 0000 1F92                push __zero_reg__
>   20 0002 0F92                push __tmp_reg__
>   21 0004 0FB6                in __tmp_reg__,__SREG__
>   22 0006 0F92                push __tmp_reg__
>   23 0008 1124                clr __zero_reg__
>   24 000a 8F93                push r24
>   25                  /* prologue end (size=6) */
>   26 000c 8091 0000           lds r24,ix
>   27 0010 8F5F                subi r24,lo8(-(1))
>   28 0012 8093 0000           sts ix,r24
>   29                  /* epilogue: frame size=0 */
>   30 0016 8F91                pop r24
>   31 0018 0F90                pop __tmp_reg__
>   32 001a 0FBE                out __SREG__,__tmp_reg__
>   33 001c 0F90                pop __tmp_reg__
>   34 001e 1F90                pop __zero_reg__
>   35 0020 1895                reti
>   36                  /* epilogue end (size=6) */
>   37                  /* function _overflow0_ size 17 (5) */
>   38                  .Lfe1:
>   39                          .size   _overflow0_,.Lfe1-_overflow0_
>   40                  .global main
>   41                          .type   main,@function
>   42                  main:
>   43                  /* prologue: frame size=0 */
>   44 0022 C0E0                ldi r28,lo8(__stack - 0)
>   45 0024 D0E0                ldi r29,hi8(__stack - 0)
>   46 0026 DEBF                out __SP_H__,r29
>   47 0028 CDBF                out __SP_L__,r28
>   48                  /* prologue end (size=4) */
>   49 002a 8FEF                ldi r24,lo8(-1)
>   50                  /* #APP */
>   51 002c 87BB                out 23,r24
>   52 002e 81BB                out 17,r24
>   53                  /* #NOAPP */
>   54 0030 8091 0000           lds r24,ix
>   55                  .L43:
>   56                  /* #APP */
>   57 0034 82BB                out 18,r24
> GAS LISTING dro.s                    page 2
> 
> 
>   58                  /* #NOAPP */
>   59 0036 FECF                rjmp .L43
>   60                  /* epilogue: frame size=0 */
>   61                  __stop_progIi__:
>   62 0038 FFCF                rjmp __stop_progIi__
>   63                  /* epilogue end (size=1) */
>   64                  /* function main size 15 (10) */
>   65                  .Lfe2:
>   66                          .size   main,.Lfe2-main
>   67                  /* File dro.c: code   32 = 0x0020 (  15), prologues  
> 10, epilogues   7 */
> GAS LISTING dro.s                    page 3
> 
> 
> DEFINED SYMBOLS
>                             *ABS*:00000000 dro.c
>                             *ABS*:0000003f __SREG__
>                             *ABS*:0000003e __SP_H__
>                             *ABS*:0000003d __SP_L__
>                             *ABS*:00000000 __tmp_reg__
>                             *ABS*:00000001 __zero_reg__
>                             *ABS*:00000002 _PC_
>                dro.s:12     .data:00000000 ix
>                dro.s:17     .text:00000000 _overflow0_
>                dro.s:42     .text:00000022 main
>                dro.s:61     .text:00000038 __stop_progIi__
>                             *ABS*:00000000 *ABS*
> 
> UNDEFINED SYMBOLS
> __stack
> 
> 
> 
> Looking at this list file it sure looks like the program starts at line 19
> which is a push instruction. Isn't the first instruction supposed to be a
> jump to the main routine? Am I missing something? I can give more info if
> needed.
> 
> Thanks!
> 
> Chris|
> 
> 
> _______________________________________________
> avr-gcc-list mailing list
> address@hidden
> http://avr.jpk.co.nz/mailman/listinfo/avr-gcc-list
> 

K.T.LAI
address@hidden