/* 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 #include /* Tested AVR check. */ #if defined (__AVR_ATmega8__) #elif defined (__AVR_ATmega8535__) #elif defined (__AVR_ATmega128__) #else # warning "rs232: not tested on this chip." #endif /* UART number. */ #if !defined (UBRRH) # if defined (UBRR0H) # if AC_RS232_PORT == 1 # define UBRRH UBRR1H # define UBRRL UBRR1L # define UCSRA UCSR1A # define UCSRB UCSR1B # define UCSRC UCSR1C # define UDR UDR1 # define SIG_UART_RECV SIG_UART1_RECV # define SIG_UART_DATA SIG_UART1_DATA # else # define UBRRH UBRR0H # define UBRRL UBRR0L # define UCSRA UCSR0A # define UCSRB UCSR0B # define UCSRC UCSR0C # define UDR UDR0 # define SIG_UART_RECV SIG_UART0_RECV # define SIG_UART_DATA SIG_UART0_DATA # endif # define PE UPE # else # error "rs232: canot find UBRR." # endif #endif /* UR selector. */ #if defined (URSEL) # define SELECTOR _BV (URSEL) #else # define SELECTOR 0 #endif /* Unimplemented features. */ #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 /* Mode. */ #define POLLING 0 #define RING 1 #define SEND_MODE AC_RS232_SEND_MODE #define RECV_MODE AC_RS232_RECV_MODE #if RECV_MODE == POLLING # define RECV_IE 0 #else # define RECV_IE _BV (RXCIE) #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)) /* Buffers. */ #if SEND_MODE == RING # define SEND_BUFFER_SIZE AC_RS232_SEND_BUFFER_SIZE # define SEND_BUFFER_MASK (SEND_BUFFER_SIZE - 1) # if SEND_BUFFER_SIZE & SEND_BUFFER_MASK # error "rs232: send buffer size must be a power of 2." # endif #endif #if RECV_MODE == RING # define RECV_BUFFER_SIZE AC_RS232_RECV_BUFFER_SIZE # define RECV_BUFFER_MASK (RECV_BUFFER_SIZE - 1) # if RECV_BUFFER_SIZE & RECV_BUFFER_MASK # error "rs232: recv buffer size must be a power of 2." # endif #endif /* Send buffer. */ #if SEND_MODE == RING uint8_t rs232_send_buffer[SEND_BUFFER_SIZE]; volatile uint8_t rs232_send_head, rs232_send_tail; #endif /* Recv buffer. */ #if RECV_MODE == RING uint8_t rs232_recv_buffer[RECV_BUFFER_SIZE]; volatile uint8_t rs232_recv_head, rs232_recv_tail; #endif /* Last error code. */ #define ERROR_BITS (_BV (FE) | _BV (DOR) | _BV (PE)) volatile uint8_t rs232_error_code; /* +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 = RECV_IE | _BV (RXEN) | _BV (TXEN); #if RECV_MODE == RING rs232_recv_head = 0; rs232_recv_tail = 0; #endif #if SEND_MODE == RING rs232_send_head = 0; rs232_send_tail = 0; #endif rs232_error_code = 0; } /** Read a char. */ uint8_t rs232_getc (void) { #if RECV_MODE == POLLING uint8_t tmperr; loop_until_bit_is_set (UCSRA, RXC); tmperr = UCSRA & ERROR_BITS; if (tmperr) rs232_error_code = tmperr; return UDR; #elif RECV_MODE == RING uint8_t tmptail = rs232_recv_tail; while (rs232_recv_head == tmptail) ; tmptail = (tmptail + 1) & RECV_BUFFER_MASK; rs232_recv_tail = tmptail; return rs232_recv_buffer[tmptail]; #endif } /** Write a char. */ void rs232_putc (uint8_t c) { #if SEND_MODE == POLLING loop_until_bit_is_set (UCSRA, UDRE); UDR = c; #elif SEND_MODE == RING uint8_t tmphead; tmphead = (rs232_send_head + 1) & SEND_BUFFER_MASK; while (tmphead == rs232_send_tail) ; rs232_send_buffer[tmphead] = c; rs232_send_head = tmphead; UCSRB |= _BV (UDRIE); #endif } /** Retrieve error condition, 0 if no error. */ uint8_t rs232_error (void) { return rs232_error_code; } /** Retrieve availlable chars. */ uint8_t rs232_poll (void) { #if RECV_MODE == POLLING return UCSRA & _BV (RXC); #elif RECV_MODE == RING return (rs232_recv_head - rs232_recv_tail) & RECV_BUFFER_MASK; #endif } #if RECV_MODE == RING /* Handle received char for ring buffer. */ INTERRUPT (SIG_UART_RECV) { uint8_t c; uint8_t tmphead; uint8_t tmperr; tmperr = UCSRA & ERROR_BITS; if (tmperr) rs232_error_code = tmperr; c = UDR; tmphead = (rs232_recv_head + 1) & RECV_BUFFER_MASK; rs232_recv_head = tmphead; /* If overflowed, clear the receive buffer. */ if (tmphead == rs232_recv_tail) rs232_error_code = 0xff; rs232_recv_buffer[tmphead] = c; } #endif /* RECV_MODE == RING */ #if SEND_MODE == RING /** Handle data register empty for ring buffer. */ INTERRUPT (SIG_UART_DATA) { uint8_t tmptail; if (rs232_send_head != rs232_send_tail) { tmptail = (rs232_send_tail + 1) & SEND_BUFFER_MASK; rs232_send_tail = tmptail; UDR = rs232_send_buffer[tmptail]; } else { UCSRB &= ~_BV (UDRIE); } } #endif /* SEND_MODE == RING */