/************************************************************************* Title: Interrupt UART library with receive/transmit circular buffers Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury File: $Id: uart.c,v 1.6.2.2 2009/11/29 08:56:12 Peter Exp $ Software: AVR-GCC 4.1, AVR Libc 1.4.6 or higher Hardware: any AVR with built-in UART, License: GNU General Public License DESCRIPTION: An interrupt is generated when the UART has finished transmitting or receiving a byte. The interrupt handling routines use circular buffers for buffering received and transmitted data. The UART_RX_BUFFER_SIZE and UART_TX_BUFFER_SIZE variables define the buffer size in bytes. Note that these variables must be a power of 2. USAGE: Refere to the header file uart.h for a description of the routines. See also example test_uart.c. NOTES: Based on Atmel Application Note AVR306 LICENSE: Copyright (C) 2006 Peter Fleury 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 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. *************************************************************************/ #include <avr/io.h> #include <avr/interrupt.h> #include <avr/pgmspace.h> #include "uart.h" /* * constants and macros */ /* size of RX/TX buffers */ #define UART_RX_BUFFER_MASK ( UART_RX_BUFFER_SIZE - 1) #define UART_TX_BUFFER_MASK ( UART_TX_BUFFER_SIZE - 1) #if ( UART_RX_BUFFER_SIZE & UART_RX_BUFFER_MASK ) #error RX buffer size is not a power of 2 #endif #if ( UART_TX_BUFFER_SIZE & UART_TX_BUFFER_MASK ) #error TX buffer size is not a power of 2 #endif #if defined(__AVR_AT90S2313__) \ || defined(__AVR_AT90S4414__) || defined(__AVR_AT90S4434__) \ || defined(__AVR_AT90S8515__) || defined(__AVR_AT90S8535__) \ || defined(__AVR_ATmega103__) /* old AVR classic or ATmega103 with one UART */ #define AT90_UART #define UART0_RECEIVE_INTERRUPT SIG_UART_RECV #define UART0_TRANSMIT_INTERRUPT SIG_UART_DATA #define UART0_STATUS USR #define UART0_CONTROL UCR #define UART0_DATA UDR #define UART0_UDRIE UDRIE #elif defined(__AVR_AT90S2333__) || defined(__AVR_AT90S4433__) /* old AVR classic with one UART */ #define AT90_UART #define UART0_RECEIVE_INTERRUPT SIG_UART_RECV #define UART0_TRANSMIT_INTERRUPT SIG_UART_DATA #define UART0_STATUS UCSRA #define UART0_CONTROL UCSRB #define UART0_DATA UDR #define UART0_UDRIE UDRIE #elif defined(__AVR_ATmega8__) || defined(__AVR_ATmega16__) || defined(__AVR_ATmega32__) \ || defined(__AVR_ATmega8515__) || defined(__AVR_ATmega8535__) \ || defined(__AVR_ATmega323__) /* ATmega with one USART */ #define ATMEGA_USART #define UART0_RECEIVE_INTERRUPT SIG_UART_RECV #define UART0_TRANSMIT_INTERRUPT SIG_UART_DATA #define UART0_STATUS UCSRA #define UART0_CONTROL UCSRB #define UART0_DATA UDR #define UART0_UDRIE UDRIE #elif defined(__AVR_ATmega163__) /* ATmega163 with one UART */ #define ATMEGA_UART #define UART0_RECEIVE_INTERRUPT SIG_UART_RECV #define UART0_TRANSMIT_INTERRUPT SIG_UART_DATA #define UART0_STATUS UCSRA #define UART0_CONTROL UCSRB #define UART0_DATA UDR #define UART0_UDRIE UDRIE #elif defined(__AVR_ATmega162__) /* ATmega with two USART */ #define ATMEGA_USART0 #define ATMEGA_USART1 #define UART0_RECEIVE_INTERRUPT SIG_USART0_RECV #define UART1_RECEIVE_INTERRUPT SIG_USART1_RECV #define UART0_TRANSMIT_INTERRUPT SIG_USART0_DATA #define UART1_TRANSMIT_INTERRUPT SIG_USART1_DATA #define UART0_STATUS UCSR0A #define UART0_CONTROL UCSR0B #define UART0_DATA UDR0 #define UART0_UDRIE UDRIE0 #define UART1_STATUS UCSR1A #define UART1_CONTROL UCSR1B #define UART1_DATA UDR1 #define UART1_UDRIE UDRIE1 #elif defined(__AVR_ATmega64__) || defined(__AVR_ATmega128__) /* ATmega with two USART */ #define ATMEGA_USART0 #define ATMEGA_USART1 #define UART0_RECEIVE_INTERRUPT SIG_UART0_RECV #define UART1_RECEIVE_INTERRUPT SIG_UART1_RECV #define UART0_TRANSMIT_INTERRUPT SIG_UART0_DATA #define UART1_TRANSMIT_INTERRUPT SIG_UART1_DATA #define UART0_STATUS UCSR0A #define UART0_CONTROL UCSR0B #define UART0_DATA UDR0 #define UART0_UDRIE UDRIE0 #define UART1_STATUS UCSR1A #define UART1_CONTROL UCSR1B #define UART1_DATA UDR1 #define UART1_UDRIE UDRIE1 #elif defined(__AVR_ATmega161__) /* ATmega with UART */ #error "AVR ATmega161 currently not supported by this libaray !" #elif defined(__AVR_ATmega169__) /* ATmega with one USART */ #define ATMEGA_USART #define UART0_RECEIVE_INTERRUPT SIG_USART_RECV #define UART0_TRANSMIT_INTERRUPT SIG_USART_DATA #define UART0_STATUS UCSRA #define UART0_CONTROL UCSRB #define UART0_DATA UDR #define UART0_UDRIE UDRIE #elif defined(__AVR_ATmega48__) ||defined(__AVR_ATmega88__) || defined(__AVR_ATmega168__) || defined(__AVR_ATmega48P__) || defined(__AVR_ATmega88P__) || defined(__AVR_ATmega168P__) || defined(__AVR_ATmega328P__) /* ATmega with one USART */ #define ATMEGA_USART0 #define UART0_RECEIVE_INTERRUPT SIG_USART_RECV #define UART0_TRANSMIT_INTERRUPT SIG_USART_DATA #define UART0_STATUS UCSR0A #define UART0_CONTROL UCSR0B #define UART0_DATA UDR0 #define UART0_UDRIE UDRIE0 #elif defined(__AVR_ATtiny2313__) #define ATMEGA_USART #define UART0_RECEIVE_INTERRUPT SIG_USART0_RX #define UART0_TRANSMIT_INTERRUPT SIG_USART0_UDRE #define UART0_STATUS UCSRA #define UART0_CONTROL UCSRB #define UART0_DATA UDR #define UART0_UDRIE UDRIE #elif defined(__AVR_ATmega329__) ||defined(__AVR_ATmega3290__) ||\ defined(__AVR_ATmega649__) ||defined(__AVR_ATmega6490__) ||\ defined(__AVR_ATmega325__) ||defined(__AVR_ATmega3250__) ||\ defined(__AVR_ATmega645__) ||defined(__AVR_ATmega6450__) /* ATmega with one USART */ #define ATMEGA_USART0 #define UART0_RECEIVE_INTERRUPT SIG_UART_RECV #define UART0_TRANSMIT_INTERRUPT SIG_UART_DATA #define UART0_STATUS UCSR0A #define UART0_CONTROL UCSR0B #define UART0_DATA UDR0 #define UART0_UDRIE UDRIE0 #elif defined(__AVR_ATmega2560__) || defined(__AVR_ATmega2561__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega1281__) || defined(__AVR_ATmega640__) /* ATmega with two USART */ #define ATMEGA_USART0 #define ATMEGA_USART1 #define UART0_RECEIVE_INTERRUPT SIG_USART0_RECV #define UART1_RECEIVE_INTERRUPT SIG_USART1_RECV #define UART0_TRANSMIT_INTERRUPT SIG_USART0_DATA #define UART1_TRANSMIT_INTERRUPT SIG_USART1_DATA #define UART0_STATUS UCSR0A #define UART0_CONTROL UCSR0B #define UART0_DATA UDR0 #define UART0_UDRIE UDRIE0 #define UART1_STATUS UCSR1A #define UART1_CONTROL UCSR1B #define UART1_DATA UDR1 #define UART1_UDRIE UDRIE1 #elif defined(__AVR_ATmega644__) /* ATmega with one USART */ #define ATMEGA_USART0 #define UART0_RECEIVE_INTERRUPT SIG_USART_RECV #define UART0_TRANSMIT_INTERRUPT SIG_USART_DATA #define UART0_STATUS UCSR0A #define UART0_CONTROL UCSR0B #define UART0_DATA UDR0 #define UART0_UDRIE UDRIE0 #elif defined(__AVR_ATmega164P__) || defined(__AVR_ATmega324P__) || defined(__AVR_ATmega644P__) /* ATmega with two USART */ #define ATMEGA_USART0 #define ATMEGA_USART1 #define UART0_RECEIVE_INTERRUPT SIG_USART_RECV #define UART1_RECEIVE_INTERRUPT SIG_USART1_RECV #define UART0_TRANSMIT_INTERRUPT SIG_USART_DATA #define UART1_TRANSMIT_INTERRUPT SIG_USART1_DATA #define UART0_STATUS UCSR0A #define UART0_CONTROL UCSR0B #define UART0_DATA UDR0 #define UART0_UDRIE UDRIE0 #define UART1_STATUS UCSR1A #define UART1_CONTROL UCSR1B #define UART1_DATA UDR1 #define UART1_UDRIE UDRIE1 #else #error "no UART definition for MCU available" #endif /* * module global variables */ static volatile unsigned char UART_TxBuf[UART_TX_BUFFER_SIZE]; static volatile unsigned char UART_RxBuf[UART_RX_BUFFER_SIZE]; static volatile unsigned char UART_TxHead; static volatile unsigned char UART_TxTail; static volatile unsigned char UART_RxHead; static volatile unsigned char UART_RxTail; static volatile unsigned char UART_LastRxError; #if defined( ATMEGA_USART1 ) static volatile unsigned char UART1_TxBuf[UART_TX_BUFFER_SIZE]; static volatile unsigned char UART1_RxBuf[UART_RX_BUFFER_SIZE]; static volatile unsigned char UART1_TxHead; static volatile unsigned char UART1_TxTail; static volatile unsigned char UART1_RxHead; static volatile unsigned char UART1_RxTail; static volatile unsigned char UART1_LastRxError; #endif SIGNAL(UART0_RECEIVE_INTERRUPT) /************************************************************************* Function: UART Receive Complete interrupt Purpose: called when the UART has received a character **************************************************************************/ { unsigned char tmphead; unsigned char data; unsigned char usr; unsigned char lastRxError; /* read UART status register and UART data register */ usr = UART0_STATUS; data = UART0_DATA; /* */ #if defined( AT90_UART ) lastRxError = (usr & (_BV(FE)|_BV(DOR)) ); #elif defined( ATMEGA_USART ) lastRxError = (usr & (_BV(FE)|_BV(DOR)) ); #elif defined( ATMEGA_USART0 ) lastRxError = (usr & (_BV(FE0)|_BV(DOR0)) ); #elif defined ( ATMEGA_UART ) lastRxError = (usr & (_BV(FE)|_BV(DOR)) ); #endif /* calculate buffer index */ tmphead = ( UART_RxHead + 1) & UART_RX_BUFFER_MASK; if ( tmphead == UART_RxTail ) { /* error: receive buffer overflow */ lastRxError = UART_BUFFER_OVERFLOW >> 8; }else{ /* store new index */ UART_RxHead = tmphead; /* store received data in buffer */ UART_RxBuf[tmphead] = data; } UART_LastRxError = lastRxError; } SIGNAL(UART0_TRANSMIT_INTERRUPT) /************************************************************************* Function: UART Data Register Empty interrupt Purpose: called when the UART is ready to transmit the next byte **************************************************************************/ { unsigned char tmptail; if ( UART_TxHead != UART_TxTail) { /* calculate and store new buffer index */ tmptail = (UART_TxTail + 1) & UART_TX_BUFFER_MASK; UART_TxTail = tmptail; /* get one byte from buffer and write it to UART */ UART0_DATA = UART_TxBuf[tmptail]; /* start transmission */ }else{ /* tx buffer empty, disable UDRE interrupt */ UART0_CONTROL &= ~_BV(UART0_UDRIE); } } /************************************************************************* Function: uart_init() Purpose: initialize UART and set baudrate Input: baudrate using macro UART_BAUD_SELECT() Returns: none **************************************************************************/ void uart_init(unsigned int baudrate) { UART_TxHead = 0; UART_TxTail = 0; UART_RxHead = 0; UART_RxTail = 0; #if defined( AT90_UART ) /* set baud rate */ UBRR = (unsigned char)baudrate; /* enable UART receiver and transmmitter and receive complete interrupt */ UART0_CONTROL = _BV(RXCIE)|_BV(RXEN)|_BV(TXEN); #elif defined (ATMEGA_USART) /* Set baud rate */ if ( baudrate & 0x8000 ) { UART0_STATUS = (1<<U2X); //Enable 2x speed baudrate &= ~0x8000; } UBRRH = (unsigned char)(baudrate>>8); UBRRL = (unsigned char) baudrate; /* Enable USART receiver and transmitter and receive complete interrupt */ UART0_CONTROL = _BV(RXCIE)|(1<<RXEN)|(1<<TXEN); /* Set frame format: asynchronous, 8data, no parity, 1stop bit */ #ifdef URSEL UCSRC = (1<<URSEL)|(3<<UCSZ0); #else UCSRC = (3<<UCSZ0); #endif #elif defined (ATMEGA_USART0 ) /* Set baud rate */ if ( baudrate & 0x8000 ) { UART0_STATUS = (1<<U2X0); //Enable 2x speed baudrate &= ~0x8000; } UBRR0H = (unsigned char)(baudrate>>8); UBRR0L = (unsigned char) baudrate; /* Enable USART receiver and transmitter and receive complete interrupt */ UART0_CONTROL = _BV(RXCIE0)|(1<<RXEN0)|(1<<TXEN0); /* Set frame format: asynchronous, 8data, no parity, 1stop bit */ #ifdef URSEL0 UCSR0C = (1<<URSEL0)|(3<<UCSZ00); #else UCSR0C = (3<<UCSZ00); #endif #elif defined ( ATMEGA_UART ) /* set baud rate */ if ( baudrate & 0x8000 ) { UART0_STATUS = (1<<U2X); //Enable 2x speed baudrate &= ~0x8000; } UBRRHI = (unsigned char)(baudrate>>8); UBRR = (unsigned char) baudrate; /* Enable UART receiver and transmitter and receive complete interrupt */ UART0_CONTROL = _BV(RXCIE)|(1<<RXEN)|(1<<TXEN); #endif }/* uart_init */ /************************************************************************* Function: uart_getc() Purpose: return byte from ringbuffer Returns: lower byte: received byte from ringbuffer higher byte: last receive error **************************************************************************/ unsigned int uart_getc(void) { unsigned char tmptail; unsigned char data; if ( UART_RxHead == UART_RxTail ) { return UART_NO_DATA; /* no data available */ } /* calculate /store buffer index */ tmptail = (UART_RxTail + 1) & UART_RX_BUFFER_MASK; UART_RxTail = tmptail; /* get data from receive buffer */ data = UART_RxBuf[tmptail]; return (UART_LastRxError << 8) + data; }/* uart_getc */ /************************************************************************* Function: uart_putc() Purpose: write byte to ringbuffer for transmitting via UART Input: byte to be transmitted Returns: none **************************************************************************/ void uart_putc(unsigned char data) { unsigned char tmphead; tmphead = (UART_TxHead + 1) & UART_TX_BUFFER_MASK; while ( tmphead == UART_TxTail ){ ;/* wait for free space in buffer */ } UART_TxBuf[tmphead] = data; UART_TxHead = tmphead; /* enable UDRE interrupt */ UART0_CONTROL |= _BV(UART0_UDRIE); }/* uart_putc */ /************************************************************************* Function: uart_puts() Purpose: transmit string to UART Input: string to be transmitted Returns: none **************************************************************************/ void uart_puts(const char *s ) { while (*s) uart_putc(*s++); }/* uart_puts */ /************************************************************************* Function: uart_puts_p() Purpose: transmit string from program memory to UART Input: program memory string to be transmitted Returns: none **************************************************************************/ void uart_puts_p(const char *progmem_s ) { register char c; while ( (c = pgm_read_byte(progmem_s++)) ) uart_putc(c); }/* uart_puts_p */ /* * these functions are only for ATmegas with two USART */ #if defined( ATMEGA_USART1 ) SIGNAL(UART1_RECEIVE_INTERRUPT) /************************************************************************* Function: UART1 Receive Complete interrupt Purpose: called when the UART1 has received a character **************************************************************************/ { unsigned char tmphead; unsigned char data; unsigned char usr; unsigned char lastRxError; /* read UART status register and UART data register */ usr = UART1_STATUS; data = UART1_DATA; /* */ lastRxError = (usr & (_BV(FE1)|_BV(DOR1)) ); /* calculate buffer index */ tmphead = ( UART1_RxHead + 1) & UART_RX_BUFFER_MASK; if ( tmphead == UART1_RxTail ) { /* error: receive buffer overflow */ lastRxError = UART_BUFFER_OVERFLOW >> 8; }else{ /* store new index */ UART1_RxHead = tmphead; /* store received data in buffer */ UART1_RxBuf[tmphead] = data; } UART1_LastRxError = lastRxError; } SIGNAL(UART1_TRANSMIT_INTERRUPT) /************************************************************************* Function: UART1 Data Register Empty interrupt Purpose: called when the UART1 is ready to transmit the next byte **************************************************************************/ { unsigned char tmptail; if ( UART1_TxHead != UART1_TxTail) { /* calculate and store new buffer index */ tmptail = (UART1_TxTail + 1) & UART_TX_BUFFER_MASK; UART1_TxTail = tmptail; /* get one byte from buffer and write it to UART */ UART1_DATA = UART1_TxBuf[tmptail]; /* start transmission */ }else{ /* tx buffer empty, disable UDRE interrupt */ UART1_CONTROL &= ~_BV(UART1_UDRIE); } } /************************************************************************* Function: uart1_init() Purpose: initialize UART1 and set baudrate Input: baudrate using macro UART_BAUD_SELECT() Returns: none **************************************************************************/ void uart1_init(unsigned int baudrate) { UART1_TxHead = 0; UART1_TxTail = 0; UART1_RxHead = 0; UART1_RxTail = 0; /* Set baud rate */ if ( baudrate & 0x8000 ) { UART1_STATUS = (1<<U2X1); //Enable 2x speed baudrate &= ~0x8000; } UBRR1H = (unsigned char)(baudrate>>8); UBRR1L = (unsigned char) baudrate; /* Enable USART receiver and transmitter and receive complete interrupt */ UART1_CONTROL = _BV(RXCIE1)|(1<<RXEN1)|(1<<TXEN1); /* Set frame format: asynchronous, 8data, no parity, 1stop bit */ #ifdef URSEL1 UCSR1C = (1<<URSEL1)|(3<<UCSZ10); #else UCSR1C = (3<<UCSZ10); #endif }/* uart_init */ /************************************************************************* Function: uart1_getc() Purpose: return byte from ringbuffer Returns: lower byte: received byte from ringbuffer higher byte: last receive error **************************************************************************/ unsigned int uart1_getc(void) { unsigned char tmptail; unsigned char data; if ( UART1_RxHead == UART1_RxTail ) { return UART_NO_DATA; /* no data available */ } /* calculate /store buffer index */ tmptail = (UART1_RxTail + 1) & UART_RX_BUFFER_MASK; UART1_RxTail = tmptail; /* get data from receive buffer */ data = UART1_RxBuf[tmptail]; return (UART1_LastRxError << 8) + data; }/* uart1_getc */ /************************************************************************* Function: uart1_putc() Purpose: write byte to ringbuffer for transmitting via UART Input: byte to be transmitted Returns: none **************************************************************************/ void uart1_putc(unsigned char data) { unsigned char tmphead; tmphead = (UART1_TxHead + 1) & UART_TX_BUFFER_MASK; while ( tmphead == UART1_TxTail ){ ;/* wait for free space in buffer */ } UART1_TxBuf[tmphead] = data; UART1_TxHead = tmphead; /* enable UDRE interrupt */ UART1_CONTROL |= _BV(UART1_UDRIE); }/* uart1_putc */ /************************************************************************* Function: uart1_puts() Purpose: transmit string to UART1 Input: string to be transmitted Returns: none **************************************************************************/ void uart1_puts(const char *s ) { while (*s) uart1_putc(*s++); }/* uart1_puts */ /************************************************************************* Function: uart1_puts_p() Purpose: transmit string from program memory to UART1 Input: program memory string to be transmitted Returns: none **************************************************************************/ void uart1_puts_p(const char *progmem_s ) { register char c; while ( (c = pgm_read_byte(progmem_s++)) ) uart1_putc(c); }/* uart1_puts_p */ #endif