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

Title:    Interrupt UART library with receive/transmit circular buffers

Author:   Peter Fleury <pfleury@gmx.ch>   http://jump.to/fleury

File:     $Id: uart.h,v 1.8.2.1 2007/07/01 11:14:38 peter Exp $

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 Doxygen manual

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.

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

//

//  @defgroup pfleury_uart UART Library

//  @code #include <uart.h> @endcode

//

//  @brief Interrupt UART library using the built-in UART with transmit and receive circular buffers.

//

//  This library can be used to transmit and receive data through the built in UART.

//

//  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 constants define

//  the size of the circular buffers in bytes. Note that these constants must be a power of 2.

//  You may need to adapt this constants to your target and your application by adding

//  CDEFS += -DUART_RX_BUFFER_SIZE=nn -DUART_RX_BUFFER_SIZE=nn to your Makefile.

//

//  @note Based on Atmel Application Note AVR306

//  @author Peter Fleury pfleury@gmx.ch  http://jump.to/fleury

//

#ifndef UART_H

#define UART_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

// @brief  UART Baudrate Expression

//  @param  xtalcpu  system clock in Mhz, e.g. 4000000L for 4Mhz

//  @param  baudrate baudrate in bps, e.g. 1200, 2400, 9600

//

#define UART_BAUD_SELECT(baudRate,xtalCpu) ((xtalCpu)/((baudRate)*16l)-1)

// @brief  UART Baudrate Expression for ATmega double speed mode

//  @param  xtalcpu  system clock in Mhz, e.g. 4000000L for 4Mhz

//  @param  baudrate baudrate in bps, e.g. 1200, 2400, 9600

//

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

// Size of the circular receive buffer, must be power of 2

#ifndef UART_RX_BUFFER_SIZE

#define UART_RX_BUFFER_SIZE 32

#endif

// Size of the circular transmit buffer, must be power of 2

#ifndef UART_TX_BUFFER_SIZE

#define UART_TX_BUFFER_SIZE 32

#endif

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

#if ( (UART_RX_BUFFER_SIZE+UART_TX_BUFFER_SIZE) >= (RAMEND-0x60 ) )

#error "size of UART_RX_BUFFER_SIZE + UART_TX_BUFFER_SIZE larger than size of SRAM"

#endif

// high byte error return code of uart_getc()

#define UART_FRAME_ERROR      0x0800              // Framing Error by UART

#define UART_OVERRUN_ERROR    0x0400              // Overrun condition by UART

#define UART_BUFFER_OVERFLOW  0x0200              // receive ringbuffer overflow

#define UART_NO_DATA          0x0100              // no receive data available

//

// function prototypes

//

//

//   @brief   Initialize UART and set baudrate

//   @param   baudrate Specify baudrate using macro UART_BAUD_SELECT()

//   @return  none

//

extern void uart_init(unsigned int baudrate);

//

//  @brief   Get received byte from ringbuffer

//

// Returns in the lower byte the received character and in the

// higher byte the last receive error.

// UART_NO_DATA is returned when no data is available.

//

//  @param   void

//  @return  lower byte:  received byte from ringbuffer

//  @return  higher byte: last receive status

//           - \b 0 successfully received data from UART

//           - \b UART_NO_DATA

//             <br>no receive data available

//           - \b UART_BUFFER_OVERFLOW

//             <br>Receive ringbuffer overflow.

//             We are not reading the receive buffer fast enough,

//             one or more received character have been dropped

//           - \b UART_OVERRUN_ERROR

//             <br>Overrun condition by UART.

//             A character already present in the UART UDR register was

//             not read by the interrupt handler before the next character arrived,

//             one or more received characters have been dropped.

//           - \b UART_FRAME_ERROR

//             <br>Framing Error by UART

//

extern unsigned int uart_getc(void);

//

//  @brief   Put byte to ringbuffer for transmitting via UART

//  @param   data byte to be transmitted

//  @return  none

//

// @brief  Initialize USART1 (only available on selected ATmegas) @see uart_init

extern void uart1_init(unsigned int baudrate);

// @brief  Get received byte of USART1 from ringbuffer. (only available on selected ATmega) @see uart_getc

extern unsigned int uart1_getc(void);

// @brief  Put byte to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_putc

//extern void uart1_putc(unsigned char data);

extern int uart1_putc(unsigned char data);

// @brief  Put string to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_puts

extern void uart1_puts(const char *s );

// @brief  Put string from program memory to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_puts_p

extern void uart1_puts_p(const char *s );

// @brief  Macro to automatically put a string constant into program memory

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

extern char *utoa1(char* buffer, const unsigned int size, unsigned int value);

#endif // UART_H