/* rs232.c */ /* n.avr.rs232 - AVR RS232 Module. {{{ * * Copyright (C) 2004 Nicolas Schodet * * 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 2 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, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * Contact : * Web: http://perso.efrei.fr/~schodet/ * Email: * }}} */ #include "rs232.h" #include /* Tested AVR check. */ #if defined (__AVR_ATmega8__) # define SELECTOR _BV (URSEL) #elif defined (__AVR_ATmega8535__) # define SELECTOR _BV (URSEL) #elif defined (__AVR_ATmega128__) # define UBRRH UBRR0H # define UBRRL UBRR0L # define UCSRA UCSR0A # define UCSRB UCSR0B # define UCSRC UCSR0C # define UDR UDR0 # define SELECTOR 0 #else # warning "rs232: not tested on this chip." #endif /* Unimplemented features. */ #if AC_RS232_INTERRUPT # error "rs232: interrupts to be implemented." #endif #if AC_RS232_CHAR_SIZE != 8 # error "rs232: char size != 8 not implemented." #endif /* Baud rate error check. */ #define UBRR_VAL (AC_FREQ / 16 / AC_RS232_BAUDRATE - 1) #define BAUDRATE (AC_FREQ / 16 / (UBRR_VAL + 1)) #if BAUDRATE - AC_RS232_BAUDRATE > 2 #warning "rs232: baud rate error > 2." #elif BAUDRATE - AC_RS232_BAUDRATE > 1 #warning "rs232: baud rate error > 1." #elif BAUDRATE - AC_RS232_BAUDRATE > 0 #warning "rs232: baud rate error > 0." #endif /* Parity. */ #define ODD (_BV (UPM1) | _BV (UPM0)) #define EVEN _BV (UPM1) #define NONE 0 #define PARITY AC_RS232_PARITY /* Stop bits. */ #if AC_RS232_STOP_BITS == 1 #define STOP_BITS 0 #elif AC_RS232_STOP_BITS == 2 #define STOP_BITS _BV (USBS) #else #error "rs232: bad stop bits value." #endif /* Character size. */ #define CHAR_SIZE (_BV (UCSZ1) | _BV (UCSZ0)) /* +AutoDec */ /* -AutoDec */ /** Initialise rs232. */ void rs232_init (void) { /* Set baud rate. */ UBRRH = UBRR_VAL >> 8; UBRRL = UBRR_VAL & 0xff; UCSRA = 0; /* Set format and enable rs232. */ UCSRC = SELECTOR | PARITY | STOP_BITS | CHAR_SIZE; UCSRB = _BV (RXEN) | _BV (TXEN); } /** Read a char. */ unsigned char rs232_getc (void) { loop_until_bit_is_set (UCSRA, RXC); return UDR; } /** Write a char. */ void rs232_putc (unsigned char c) { loop_until_bit_is_set (UCSRA, UDRE); UDR = c; }