2.2. Tips¶

• set location of .mmcu without that, you get a avr-ld: section .mmcu loaded at [XXX,YYY] overlaps section .data loaded at [XXX,YYY]:

  -Wl,--undefined=_mmcu,--section-start=.mmcu=0x910000
  

• a printf-like function

  • add this function to your library:

    static int
    uart_putchar(char c, FILE *stream) {
      if (c == '\n')
      uart_putchar('\r', stream);
      loop_until_bit_is_set(UCSR0A, UDRE0);
      UDR0 = c;
      return 0;
    }
    

  • create a file descriptor:

    static FILE mystdout = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE);
    

  • and set the file descriptor for stdout to your previous generated file descriptor:

    stdout = &mystdout;