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#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 1.7.2.5 2005/08/14 11:25:41 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 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
*/
 
/**@{*/

#ifdef __cplusplus
extern "C" {
#endif

#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
*/
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))

/**@}*/

#ifdef __cplusplus
}
#endif

#endif // UART_H

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