Hi,
"I do *not* want the ISR to be called". I guess you do not want the interrupt
to be enabled. If you do not start the timer (as the interrupt is timer
related) this interrupt will never occur. If you are using the timer for
something else and need the timer running, then you need not explicitly enable
timer overflow interrupt (see TIMSK register bits). In the while loop, you are
always setting the port bit which I guess is connected to the LED and the LED
will glow when this bit is 1. Suggest toggling the LED through a while loop
with delays (large enough to be able to see LED flashing) inserted. Regards,
Parthasaradhi
Hyderabad
On Sunday, May 8, 2016 3:06 PM, "a...@tuta.io" <a...@tuta.io> wrote:
Thank you for your instant response.
I am sorry if I was unclear about that: I do *not* want the ISR to be called.
The LED should turn on because I enable it in main(), however, the uC goes
straight to the ISR!
For example, if I set the LED to high in the ISR and set it to low in main(),
it will be set to high and the LED will turn on when I flash it. Even though I
used cli()!
This behavior appears to depend on -Os, so I guess I am either using the tools
incorrectly, or there is a bug in the optimization code.
8. Mai 2016 11:22 von partha_nay...@yahoo.com:
First off, you are disabling global interrupts (cli ()). You need to enable
them (sei ()). I presume you are toggling the LED in ISR, if so the LED will
not toggle as interrupts are disabled. Regards,
Parthasaradhi
Hyderabad
On Sunday, May 8, 2016 2:40 PM, "a...@tuta.io" <a...@tuta.io> wrote:
Hello,
I have been working on a project for some time and at some point, everything
just stopped working. It appears that as soon as I include an ISR in my C code,
the main function won't even be called anymore. I reduced my code to this:
#include <avr/io.h>
#include <avr/interrupt.h>
int main (void) {
cli();
DDRB = 0xff;
while(1) PORTB |= (1 << PB5);
return 0;
}
ISR(TIMER0_OVF_vect) {}
But the LED just won't turn on. The strange thing is: If I remove the ISR at
the bottom without changing anything else, even keeping the include, everything
works. If I remove the -Os option from gcc but keep the ISR, everything works.
I use these commands to compile, link and flash it:
F_CPU=16000000L
avr-gcc -Wall -DF_CPU=$F_CPU -c -mmcu=atmega168 -Os main.c -o main.o
avr-ld -mavr5 -o led-test.elf main.o
avr-objcopy -O ihex led-test.elf led-test.hex
sudo avrdude -c avrisp2 -p atmega168 -P usb -b 57600 -U flash:w:led-test.hex
I am quite new to the avr tools so I might just have made a silly mistake, so I
would appreciate any tips!
Thank you!
LSB:
Distributor ID: Ubuntu
Description: Ubuntu 16.04 LTS
Release: 16.04
Codename: xenial
Output of avr-gcc -v:
Using built-in specs.
Reading specs from /usr/lib/gcc/avr/4.9.2/device-specs/specs-avr2
COLLECT_GCC=avr-gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/avr/4.9.2/lto-wrapper
Target: avr
Configured with: ../src/configure -v --enable-languages=c,c++ --prefix=/usr/lib
--infodir=/usr/share/info --mandir=/usr/share/man --bindir=/usr/bin
--libexecdir=/usr/lib --libdir=/usr/lib --enable-shared --with-system-zlib
--enable-long-long --enable-nls --without-included-gettext --disable-libssp
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=avr CFLAGS='-g -O2
-fstack-protector-strong -Wformat ' CPPFLAGS=-D_FORTIFY_SOURCE=2 CXXFLAGS='-g
-O2 -fstack-protector-strong -Wformat ' FCFLAGS='-g -O2
-fstack-protector-strong' FFLAGS='-g -O2 -fstack-protector-strong' GCJFLAGS='-g
-O2 -fstack-protector-strong' LDFLAGS='-Wl,-Bsymbolic-functions -Wl,-z,relro'
OBJCFLAGS='-g -O2 -fstack-protector-strong -Wformat ' OBJCXXFLAGS='-g -O2
-fstack-protector-strong -Wformat '
Thread model: single
gcc version 4.9.2 (GCC)
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