Preston Wilson wrote: > "Robert L Cochran" wrote: > > >> [EMAIL PROTECTED] butterfly]$ avr-gcc -I. -I/usr/avr/include -std=c99 -g >> -mmcu=atmega169 -Os -fpack-struct -fshort-enums -funsigned-bitfields >> -funsigned-char -Wall -Wstrict-prototypes -Wa,-ahlms=blinky.lst -c >> blinky.c -o blinky.o >> In file included from blinky.c:4: >> /usr/lib/gcc/avr/4.1.2/../../../../avr/include/util/delay.h:84:3: >> warning: #warning "F_CPU not defined for <util/delay.h>" >> >> What values for F_CPU do I need? >> > > The Butterfly is setup to run on the internal oscillator, which can run up > to 8MHz (depends upon the voltage supplied to the part), and the way it is > shipped, it is configured with the clock prescale set to 8, so that results > in a 1MHz clock. If you have not modified the CKSEL and CKDIV8 fuses, and > you do not mess with the clock prescaler register(s) in your code, then that > is what you are working with, and you need to set F_CPU to 1000000 (or > 1MHz). > > Look at the section on system clock source in the datasheet for the > ATmega169 where it describes all of the fuse and register settings that > impact the part. > > -Preston > > > Thank you! This is the first time I've really tried programming the Butterfly outside of WinAVR. I need to spend some time with the datasheet. I've also learned to add -std=c99 to my avr-gcc incantation or it will complain about (for int i = 1...) loops.
Bob Cochran > > _______________________________________________ AVR-chat mailing list AVR-chat@nongnu.org http://lists.nongnu.org/mailman/listinfo/avr-chat
