I'm (at long last) trying to switch from using Windows to using Ubuntu for my AVR development. I'm using AVR-GCC 4.5.3 on Ubuntu 12.04. I'm using the Eclipse IDE with the AVR-GCC plugin. I'm getting the following error trace from the compiler:
In file included from ../soft_uart.c:16:0:
/usr/lib/gcc/avr/4.5.3/../../../avr/include/util/delay.h: In function ‘soft_uart_init’:
/usr/lib/gcc/avr/4.5.3/../../../avr/include/util/delay.h:153:28: error: __builtin_avr_delay_cycles expects an integer constant.
/usr/lib/gcc/avr/4.5.3/../../../avr/include/util/delay.h: In function ‘delay_bit_time’:
/usr/lib/gcc/avr/4.5.3/../../../avr/include/util/delay.h:230:28: error: __builtin_avr_delay_cycles expects an integer constant.
line 16 of soft_uart.c is just the #include <util/delay.h> line.
I use _delay_ms and _delay_us in exactly six lines of code. The first two are:
_delay_ms(BIT_TIME_US * 2);
_delay_us(BIT_TIME_US);
which both depend on the following definitions:
#define BAUD_RATE 2400
#define BIT_TIME_US (1000000.0 / BAUD_RATE)
and then also the following four lines:
_delay_ms(100);
_delay_ms(250);
_delay_ms(500);
_delay_ms(2000);
I've read
this thread on avr-freaks and also
this bug-report, but nothing jumps out at me as being relevant. Obviously, my arguments are all well defined constants at compile-time. The same error message shows up as long as at least one of those six lines is not commented out.
Every single avr-gcc call issued by Eclipse contains the argument -DF_CPU=3686400UL so F_CPU is also a well defined constant. What the heck is going on here?
Regards,
Vic