I want to log out from stm32f405 via usart. In my syscall.c file i realize function to print via usart:
int _write(int file, char *ptr, int len)
{
int todo;
for (todo = 0; todo < len; todo++)
{
usart_send_char( *ptr++ );
}
return len;
}
Function usart_send_char( *ptr++ ); work as expected. But when i call:
printf("%s, %d, %3.2f\r\n", "asd", 777, 13.2 );
I get:
asd, 777, 0.00
The float variable not printed correctly.
Makefile:
PROCESSOR = -mcpu=cortex-m4 -mthumb -mfloat-abi=softfp -mfpu=fpv4-sp-d16
CFLAGS += $(PROCESSOR) $(INCLUDES) $(STFLAGS) -Wall -fno-strict-aliasing $(C_PROFILE)
LDFLAGS = $(PROCESSOR) -Wl,-Map=$(PROG).map,--cref,--gc-sections
Used compilator:
Sourcery CodeBench Lite 2014.05-28
Where i am mistaken?
Answer
I haven't used Sourcery Codebench gcc for STM32F4, but with the GCC ARM Embedded toolchain, floating point support in printf isn't enabled by default. To enable, add -u _printf_float to your LDFLAGS.