+ * \defgroup uart_i
+ * \brief declaration for interrupt based uart
+ * \details
+ * This implementation of the uart-interface of AVR microcontrollers uses the
+ * interrup architecture and can be used to handle serial communication in the
+ * background.
+ * The uart is configured at compile-time by some special defines starting with
+ * \a UART0_ for configuring the first uart and \a UART1_ for the second.
+ * Some settings use symbolic values defined in uart_defs.h .
+ * The following options are available:
+ * - \a *_I enables the interrupt based driver for this uart
+ * - \a 0 disables driver
+ * - \a 1 enables driver
+ * - \a *_BAUD_RATE sets the baudrate for this uart (value is the baudrate)
+ * - \a *_STOPBITS sets the amount of stop bits for this uart
+ * - \a UART_STOPBITS_1 for one stop bit
+ * - \a UART_STOPBITS_2 for two stop bits
+ * - \a *_DATABITS sets the amount of data bits for this uart
+ * - \a UART_DATABITS_5 for five data bits
+ * - \a UART_DATABITS_6 for six data bits
+ * - \a UART_DATABITS_7 for seven data bits
+ * - \a UART_DATABITS_8 for eight data bits
+ * - \a *_PARATY sets the mode for paraty calculation for this uart
+ * - \a UART_PARATY_NONE ignore paraty
+ * - \a UART_PARATY_ODD odd paraty
+ * - \a UART_PARATY_EVEN even paraty
+ * - \a *_RXBUFFER_SIZE size of the recieve buffer in bytes
+ * - \a *_TXBUFFER_SIZE size of the transmitt buffer in bytes
+ * - \a *_SWFLOWCTRL enable/diasable software flow control (via XON & XOFF)
+ * - \a 0 disable software flow control
+ * - \a 1 enable software flow control
+ * - \a *_THRESH_HIGH set upper limit for the rx buffer, which causes an XOFF
+ * to be send when crossed (only relevant if software flow
+ * control is enabled)
+ * - \a *_THRESH_LOW set lower limit for the rx buffer, which causes an XON to
+ * be send when crossed and an XOFF has been send previously
+ * (only relevant if software flow control is enabled)
+ * - \a *_HOOK enable/disable implementation of the hook feature
+ * (\ref uart0_sethook())
+ * - \a 0 disable hook feature
+ * - \a 1 enable hook feature
+ *