uart.h

#ifndef UART_H
#define UART_H

/************************************************************************
Title:    Interrupt UART library with receive/transmit circular buffers
Author:   Andy Gock
Software: AVR-GCC 4.1, AVR Libc 1.4
Hardware: any AVR with built-in UART, tested on AT90S8515 & ATmega8 at 4 Mhz
License:  GNU General Public License 
Usage:    see README.md and Doxygen manual

Based on original library by Peter Fluery, Tim Sharpe, Nicholas Zambetti.

https://github.com/andygock/avr-uart

LICENSE:

    Copyright (C) 2012 Andy Gock
    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.

************************************************************************/

/************************************************************************
uart_available, uart_flush, uart1_available, and uart1_flush functions
were adapted from the Arduino HardwareSerial.h library by Tim Sharpe on 
11 Jan 2009.  The license info for HardwareSerial.h is as follows:

  HardwareSerial.h - Hardware serial library for Wiring
  Copyright (c) 2006 Nicholas Zambetti.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
************************************************************************/

#include <stdint.h>
#include <avr/io.h>

#if (__GNUC__ * 100 + __GNUC_MINOR__) < 304
#error "This library requires AVR-GCC 3.4 or later, update to newer AVR-GCC compiler !"
#endif

/*
 * constants and macros
 */

/* Enable USART 1, 2, 3 as required */
/* Can be defined in compiler symbol setup with -D option (preferred) */
#ifndef USART0_ENABLED
    #define USART0_ENABLED 
#endif
//#define USART1_ENABLED
//#define USART2_ENABLED 
//#define USART3_ENABLED

/* Set size of receive and transmit buffers */

#ifndef UART_RX0_BUFFER_SIZE
    #define UART_RX0_BUFFER_SIZE 128 
#endif
#ifndef UART_RX1_BUFFER_SIZE
    #define UART_RX1_BUFFER_SIZE 128 
#endif
#ifndef UART_RX2_BUFFER_SIZE
    #define UART_RX2_BUFFER_SIZE 128 
#endif
#ifndef UART_RX3_BUFFER_SIZE
    #define UART_RX3_BUFFER_SIZE 128 
#endif

#ifndef UART_TX0_BUFFER_SIZE
    #define UART_TX0_BUFFER_SIZE 128 
#endif
#ifndef UART_TX1_BUFFER_SIZE
    #define UART_TX1_BUFFER_SIZE 128 
#endif
#ifndef UART_TX2_BUFFER_SIZE
    #define UART_TX2_BUFFER_SIZE 128 
#endif
#ifndef UART_TX3_BUFFER_SIZE
    #define UART_TX3_BUFFER_SIZE 128 
#endif

/* Check buffer sizes are not too large for 8-bit positioning */

#if (UART_RX0_BUFFER_SIZE > 256 & !defined(USART0_LARGE_BUFFER))
    #error "Buffer too large, please use -DUSART0_LARGE_BUFFER switch in compiler options"
#endif

#if (UART_RX1_BUFFER_SIZE > 256 & !defined(USART1_LARGE_BUFFER))
    #error "Buffer too large, please use -DUSART1_LARGE_BUFFER switch in compiler options"
#endif

#if (UART_RX2_BUFFER_SIZE > 256 & !defined(USART2_LARGE_BUFFER))
    #error "Buffer too large, please use -DUSART2_LARGE_BUFFER switch in compiler options"
#endif

#if (UART_RX3_BUFFER_SIZE > 256 & !defined(USART3_LARGE_BUFFER))
    #error "Buffer too large, please use -DUSART3_LARGE_BUFFER switch in compiler options"
#endif

/* Check buffer sizes are not too large for *_LARGE_BUFFER operation (16-bit positioning) */

#if (UART_RX0_BUFFER_SIZE > 32768)
    #error "Buffer too large, maximum allowed is 32768 bytes"
#endif

#if (UART_RX1_BUFFER_SIZE > 32768)
    #error "Buffer too large, maximum allowed is 32768 bytes"
#endif

#if (UART_RX2_BUFFER_SIZE > 32768)
    #error "Buffer too large, maximum allowed is 32768 bytes"
#endif

#if (UART_RX3_BUFFER_SIZE > 32768)
    #error "Buffer too large, maximum allowed is 32768 bytes"
#endif

#define UART_BAUD_SELECT(baudRate,xtalCpu) (((xtalCpu)+8UL*(baudRate))/(16UL*(baudRate))-1UL)

#define UART_BAUD_SELECT_DOUBLE_SPEED(baudRate,xtalCpu) ((((xtalCpu)+4UL*(baudRate))/(8UL*(baudRate))-1)|0x8000)

/* test if the size of the circular buffers fits into SRAM */

#if defined(USART0_ENABLED) && ( (UART_RX0_BUFFER_SIZE+UART_TX0_BUFFER_SIZE) >= (RAMEND-0x60))
    #error "size of UART_RX0_BUFFER_SIZE + UART_TX0_BUFFER_SIZE larger than size of SRAM"
#endif

#if defined(USART1_ENABLED) && ( (UART_RX1_BUFFER_SIZE+UART_TX1_BUFFER_SIZE) >= (RAMEND-0x60))
    #error "size of UART_RX1_BUFFER_SIZE + UART_TX1_BUFFER_SIZE larger than size of SRAM"
#endif

#if defined(USART2_ENABLED) && ( (UART_RX2_BUFFER_SIZE+UART_RX2_BUFFER_SIZE) >= (RAMEND-0x60))
    #error "size of UART_RX2_BUFFER_SIZE + UART_TX2_BUFFER_SIZE larger than size of SRAM"
#endif

#if defined(USART3_ENABLED) && ( (UART_RX3_BUFFER_SIZE+UART_RX3_BUFFER_SIZE) >= (RAMEND-0x60))
    #error "size of UART_RX3_BUFFER_SIZE + UART_TX3_BUFFER_SIZE larger than size of SRAM"
#endif

/* 
** high byte error return code of uart_getc()
*/
#define UART_FRAME_ERROR      0x0800              
#define UART_OVERRUN_ERROR    0x0400              
#define UART_BUFFER_OVERFLOW  0x0200              
#define UART_NO_DATA          0x0100              
/* Macros, to allow use of legacy names */

#define uart_init(b)      uart0_init(b)

#define uart_getc()       uart0_getc()

#define uart_peek()       uart0_peek()

#define uart_putc(d)      uart0_putc(d)

#define uart_puts(s)      uart0_puts(s)

#define uart_puts_p(s)    uart0_puts_p(s)

#define uart_available()  uart0_available()

#define uart_flush()      uart0_flush()

/*
** function prototypes
*/

extern void uart0_init(uint16_t baudrate);


extern uint16_t uart0_getc(void);

extern uint16_t uart0_peek(void);

extern void uart0_putc(uint8_t data);


extern void uart0_puts(const char *s);


extern void uart0_puts_p(const char *s);

#define uart_puts_P(__s)       uart0_puts_p(PSTR(__s))

#define uart0_puts_P(__s)      uart0_puts_p(PSTR(__s))

extern uint16_t uart0_available(void);

extern void uart0_flush(void);


extern void uart1_init(uint16_t baudrate);

extern uint16_t uart1_getc(void);

extern uint16_t uart1_peek(void);

extern void uart1_putc(uint8_t data);

extern void uart1_puts(const char *s);

extern void uart1_puts_p(const char *s);

#define uart1_puts_P(__s)       uart1_puts_p(PSTR(__s))

extern uint16_t uart1_available(void);

extern void uart1_flush(void);


extern void uart2_init(uint16_t baudrate);

extern uint16_t uart2_getc(void);

extern uint16_t uart2_peek(void);

extern void uart2_putc(uint8_t data);

extern void uart2_puts(const char *s);

extern void uart2_puts_p(const char *s);

#define uart2_puts_P(__s)       uart2_puts_p(PSTR(__s))

extern uint16_t uart2_available(void);

extern void uart2_flush(void);


extern void uart3_init(uint16_t baudrate);

extern uint16_t uart3_getc(void);

extern uint16_t uart3_peek(void);

extern void uart3_putc(uint8_t data);

extern void uart3_puts(const char *s);

extern void uart3_puts_p(const char *s);

#define uart3_puts_P(__s)       uart3_puts_p(PSTR(__s))

extern uint16_t uart3_available(void);

extern void uart3_flush(void);

#endif // UART_H