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Thank you for the input, Peter and Cory.
Peter: The 3 chips I tried, were ordered at the same time, so if there
would be a manufacturing error the risk that all 3 are affected are
still there, I guess. I'm using a stabilized DC power supply which is
connected to Vcc and Gnd supplying 5 volts. I do not have a
possibility to try another chip except these 3 I have. But I am going
to order some and test, if we can't find anything wrong with the
disassembly.
Cory: No, setting PB0 to 1 in DDRB two times in main doesn't change
anything. Doing "DDRB = 0xFF;" doesn't change anything. However, if I
put that line of code inside the "turn_on_pb" function it works as
expected.
I have attatched two first code examples with dumping done on the
elf-file with the sections included aswell:
=== // Bare minimum start (faulty behavior) ===
#include <avr/io.h>
void turn_on_pb(void);
int main(void)
{
DDRB |= (1 << PB0);
turn_on_pb();
for (;;) {
}
return 0;
}
void turn_on_pb(void)
{
PORTB |= (1 << PB0);
}
- --- --- Disassembly start --- ---
example.elf: file format elf32-avr
Sections:
Idx Name Size VMA LMA File off Algn
0 .text 00000008 00000000 00000000 00000054 2**1
Disassembly of section .text:
00000000 <main>:
#include <avr/io.h>
int main(void)
{
PORTB = 0xFF;
0: 8f ef ldi r24, 0xFF ; 255
2: 85 b9 out 0x05, r24 ; 5
DDRB = 0xFF;
4: 84 b9 out 0x04, r24 ; 4
6: ff cf rjmp .-2 ; 0x6 <__zero_reg__+0x5>
- --- --- Disassembly end --- ---
=== \\ Bare minimum end ===
=== // Static bare minimum start (expected behavior) ===
#include <avr/io.h>
static void turn_on_pb(void);
int main(void)
{
DDRB |= (1 << PB0);
turn_on_pb();
for (;;) {
}
return 0;
}
static void turn_on_pb(void)
{
PORTB |= (1 << PB0);
}
- --- --- Disassembly start --- ---
example.elf: file format elf32-avr
Sections:
Idx Name Size VMA LMA File off Algn
0 .text 00000006 00000000 00000000 00000054 2**1
Disassembly of section .text:
00000000 <main>:
static void turn_on_pb(void);
int main(void)
{
DDRB |= (1 << PB0);
0: 20 9a sbi 0x04, 0 ; 4
return 0;
}
static void turn_on_pb(void)
{
PORTB |= (1 << PB0);
2: 28 9a sbi 0x05, 0 ; 5
4: ff cf rjmp .-2 ; 0x4 <__zero_reg__+0x3>
- --- --- Disassembly end --- ---
=== \\ Static bare minimum end ===
On 3/1/12 2:15 PM, Peter Fuhrmann wrote:
>
> The assembly looks correct. This should work. Maybe the RAM of your
> AVR is faulty so function return doesn't work, or the powersupply
> is unstable. I think this is most likely to be a hardware problem.
> Another possibilitty ist that the Stack Pointer isn't set up
> properly in the startup code, so the function can not return.
>
> Could you try another chip or another Board ?
>
> Best Regards, Peter
>
> _______________________________________________ AVR-GCC-list
> mailing list AVR-GCC-list@nongnu.org
> https://lists.nongnu.org/mailman/listinfo/avr-gcc-list
>
On 3/1/12 2:17 PM, Cory Cross wrote:
> You should dump example.elf not example.o, could identify linking
problem.
> Does it work if you double the DDRB |=... command so it runs
> twice?
>
> Cory
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