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uart.h
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#ifndef UART_H
#define UART_H
/************************************************************************
Title: Interrupt UART library with receive/transmit circular buffers
Author: Peter Fleury <[email protected]> http://jump.to/fleury
File: $Id: uart.h,v 1.12 2012/11/19 19:52:27 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 [email protected] http://jump.to/fleury
*/
/**@{*/
#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. 4000000UL for 4Mhz
* @param baudrate baudrate in bps, e.g. 1200, 2400, 9600
*/
#define UART_BAUD_SELECT(baudRate,xtalCpu) (((xtalCpu) + 8UL * (baudRate)) / (16UL * (baudRate)) -1UL)
/** @brief UART Baudrate Expression for ATmega double speed mode
* @param xtalcpu system clock in Mhz, e.g. 4000000UL for 4Mhz
* @param baudrate baudrate in bps, e.g. 1200, 2400, 9600
*/
#define UART_BAUD_SELECT_DOUBLE_SPEED(baudRate,xtalCpu) ( ((((xtalCpu) + 4UL * (baudRate)) / (8UL * (baudRate)) -1UL)) | 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 0x1000 /* Framing Error by UART */
#define UART_OVERRUN_ERROR 0x0800 /* Overrun condition by UART */
#define UART_PARITY_ERROR 0x0400 /* Parity Error 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
*/
extern void uart_putc(unsigned char data);
/**
* @brief Put string to ringbuffer for transmitting via UART
*
* The string is buffered by the uart library in a circular buffer
* and one character at a time is transmitted to the UART using interrupts.
* Blocks if it can not write the whole string into the circular buffer.
*
* @param s string to be transmitted
* @return none
*/
extern void uart_puts(const char *s );
/**
* @brief Put string from program memory to ringbuffer for transmitting via UART.
*
* The string is buffered by the uart library in a circular buffer
* and one character at a time is transmitted to the UART using interrupts.
* Blocks if it can not write the whole string into the circular buffer.
*
* @param s program memory string to be transmitted
* @return none
* @see uart_puts_P
*/
extern void uart_puts_p(const char *s );
/**
* @brief Macro to automatically put a string constant into program memory
*/
#define uart_puts_P(__s) uart_puts_p(PSTR(__s))
/** @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);
/** @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))
/**@}*/
#endif // UART_H