uart.h

#ifndef UART_H
#define UART_H
/************************************************************************
Title:    Interrupt UART library with receive/transmit circular buffers
Author:   Peter Fleury <pfleury@gmx.ch>   http://jump.to/fleury
File:     $Id: uart.h,v 1.7.2.2 2005/01/27 19:23:51 Peter Exp $
Software: AVR-GCC 3.3
Hardware: any AVR with built-in UART, tested on AT90S8515 at 4 Mhz
Usage:    see Doxygen manual
************************************************************************/

/** 
 *  @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 size to your target and your application.
 *
 *  @note Based on Atmel Application Note AVR306
 *  @author Peter Fleury pfleury@gmx.ch  http://jump.to/fleury
 */
 
/*@{*/


#if (__GNUC__ * 100 + __GNUC_MINOR__) < 303
#error "This library requires AVR-GCC 3.3 or later, update to newer AVR-GCC compiler !"
#endif


#define ENABLE_RX		// Empfangsroutinen verwenden
#define ENABLE_TX		// Senderoutinen verwenden
#define SIMPLE_UART		// nur einfache Sende und Empfangsroutinen verwenden
//#define DISABLE_TXBUF		// Sendepuffer abschalten
#define RX_COUNT		// Anzahl der Bytes im Empfangsbuffer zählen (z.B. für CTS)
//#define USE_CTS			// CTS Handshaking
//#define NO_UART_INT		// kein Interrupt, nur Polling

#define CTS		PORTD_2		// CTS Pin (muss per Hand auf Ausgang gesetzt werden !!!)


/*
** constants and macros
*/

/** @brief  UART Baudrate Expression
 *  @param  xtalcpu  system clock in Mhz           
 *  @param  baudrate baudrate in bps, e.g. 1200, 2400, 9600     
 */
#define UART_BAUD_SELECT(baudRate,xtalCpu) ((((xtalCpu)+(baudRate)*8UL))/((baudRate)*16UL)-1)


/** Size of the circular receive buffer, must be power of 2 */
#define UART_RX_BUFFER_SIZE 256
/** Size of the circular transmit buffer, must be power of 2 */
#define UART_TX_BUFFER_SIZE 128


/** Size of the circular receive buffer, must be power of 2 */
#define UART1_RX_BUFFER_SIZE 32
/** Size of the circular transmit buffer, must be power of 2 */
#define UART1_TX_BUFFER_SIZE 32


#ifndef P
#define P(s) ({static const char c[] __attribute__ ((progmem)) = s;c;})
#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
 */
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(P(__s))


/*@}*/

extern unsigned char uart_getchar(void);
#if ((defined RX_COUNT)&&(UART_RX_BUFFER_SIZE>=256))
extern unsigned short uart_data(void);
#else
extern unsigned char uart_data(void);
#endif

extern void uart1_init(unsigned int baudrate);
extern unsigned int uart1_getc(void);
extern void uart1_putc(unsigned char data);
extern void uart1_puts(const char *s );
extern void uart1_puts_p(const char *s );
#define uart1_puts_P(__s)       uart1_puts_p(P(__s))



#endif // UART_H