/*
    This file is part of the AVR-uart_ni.
    Copyright (C) 2009 Daniel Otte (daniel.otte@rub.de)

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/* #include <util/setbaud.h> */
/* we use a modifyed version of util/setbaud where the UL suffix is removed
 * since the preprocessor can not handle that.
 */

#ifndef F_CPU
#  error "uart_i requires F_CPU to be defined"
#endif

#ifndef BAUD
#  error "uart_i requires UART0_BAUD_RATE to be defined"
#endif

#if !(F_CPU)
#  error "F_CPU must be a constant value"
#endif

#if !(BAUD)
#  error "UART0_BAUD_RATE must be a constant value"
#endif

#undef USE_2X

/* Baud rate tolerance is 2 % unless previously defined */
#ifndef BAUD_TOL
#  define BAUD_TOL 2
#endif

#define UBRR_VALUE (((F_CPU) + 8 * (BAUD)) / (16 * (BAUD)) -1)

#if 100 * (F_CPU) > \
  (16 * ((UBRR_VALUE) + 1)) * (100 * (BAUD) + (BAUD) * (BAUD_TOL))
#  define USE_2X 1
#elif 100 * (F_CPU) < \
  (16 * ((UBRR_VALUE) + 1)) * (100 * (BAUD) - (BAUD) * (BAUD_TOL))
#  define USE_2X 1
#else
#  define USE_2X 0
#endif

#if USE_2X
/* U2X required, recalculate */
#undef UBRR_VALUE
#define UBRR_VALUE (((F_CPU) + 4 * (BAUD)) / (8 * (BAUD)) -1)

#if 100 * (F_CPU) > \
  (8 * ((UBRR_VALUE) + 1)) * (100 * (BAUD) + (BAUD) * (BAUD_TOL))
#  warning "Baud rate achieved is higher than allowed"
#endif

#if 100 * (F_CPU) < \
  (8 * ((UBRR_VALUE) + 1)) * (100 * (BAUD) - (BAUD) * (BAUD_TOL))
#  warning "Baud rate achieved is lower than allowed"
#endif

#endif /* USE_U2X */

#ifdef UBRR_VALUE
#  define UBRRL_VALUE ((UBRR_VALUE) & 0xff)
#  define UBRRH_VALUE ((UBRR_VALUE) >> 8)
#endif