//
// uart.h : UART driver with buffer support
//
//	This library provides both buffered and unbuffered transmit and receive
//	functions for the AVR processor UART.� Buffered access means that the
//	UART can transmit and receive data in the "background", while your code
//	continues executing.� Also included are functions to initialize the
//	UART, set the baud rate, flush the buffers, and check buffer status.
//
//	For full text output functionality, you may wish to use the rprintf
//	functions along with this driver.
//
//	Most Atmel AVR-series processors contain one or more hardware UARTs
//	(aka, serial ports).  UART serial ports can communicate with other 
//	serial ports of the same type, like those used on PCs.  In general,
//	UARTs are used to communicate with devices that are RS-232 compatible
//	(RS-232 is a certain kind of serial port).
//
//	By far, the most common use for serial communications on AVR processors
//	is for sending information and data to a PC running a terminal program.
//	Here is an exmaple:
// 	uartInit();					// initialize UART (serial port)
// 	uartSetBaudRate(9600);		// set UART speed to 9600 baud
// 	rprintfInit(uartSendByte);  // configure rprintf to use UART for output
// 	rprintf("Hello World\r\n");	// send "hello world" message via serial port
//
// 	The CPU frequency (F_CPU) must be set correctly in \c global.h
//	for the UART library to calculate correct baud rates.  Furthermore,
//	certain CPU frequencies will not produce exact baud rates due to
//	integer frequency division round-off.  See your AVR processor's
//	datasheet for full details.
//
// Copyright (c) 2000-2002 Pascal Stang
//
// 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 (at your option) 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.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
//
// $Id$


#ifndef UART_H
#define UART_H

#include "global.h"
#include "buffer.h"

//! Default uart baud rate.
/// This is the default speed after a uartInit() command,
/// and can be changed by using uartSetBaudRate().
#ifndef UART_DEFAULT_BAUD_RATE
#define UART_DEFAULT_BAUD_RATE	9600
#endif

// buffer memory allocation defines
// buffer sizes
#ifndef UART_TX_BUFFER_SIZE
//! Number of bytes for uart transmit buffer.
/// Do not change this value in uart.h, but rather override
/// it with the desired value defined in your project's global.h
#define UART_TX_BUFFER_SIZE		0x0040
#endif
#ifndef UART_RX_BUFFER_SIZE
//! Number of bytes for uart receive buffer.
/// Do not change this value in uart.h, but rather override
/// it with the desired value defined in your project's global.h
#define UART_RX_BUFFER_SIZE		0x0040
#endif

// define this key if you wish to use
// external RAM for the	UART buffers
//#define UART_BUFFER_EXTERNAL_RAM
#ifdef UART_BUFFER_EXTERNAL_RAM
	// absolute address of uart buffers
	#define UART_TX_BUFFER_ADDR	0x1000
	#define UART_RX_BUFFER_ADDR	0x1100
#endif

//! Type of interrupt handler to use for uart interrupts.
/// Value may be SIGNAL or INTERRUPT.
/// \warning Do not change unless you know what you're doing.
#ifndef UART_INTERRUPT_HANDLER
#define UART_INTERRUPT_HANDLER	SIGNAL
#endif

// compatibility with most newer processors
#ifdef UCSRB
	#define UCR					UCSRB
#endif
// compatibility with old Mega processors
#if defined(UBRR) && !defined(UBRRL)
	#define	UBRRL				UBRR
#endif
// compatibility with megaXX8 processors
#if	defined(__AVR_ATmega48__)	|| \
	defined(__AVR_ATmega88__)	|| \
	defined(__AVR_ATmega168__)	|| \
	defined(__AVR_ATmega644__)
	#define UDR			UDR0
	#define UCR			UCSR0B
	#define RXCIE			RXCIE0
	#define TXCIE			TXCIE0
	#define RXC			RXC0
	#define TXC			TXC0
	#define RXEN			RXEN0
	#define TXEN			TXEN0
	#define UBRRL			UBRR0L
	#define UBRRH			UBRR0H
	#define SIG_UART_TRANS		SIG_USART_TRANS
	#define SIG_UART_RECV		SIG_USART_RECV
	#define SIG_UART_DATA		SIG_USART_DATA
#endif
// compatibility with mega169 processors
#if	defined(__AVR_ATmega169__)
	#define SIG_UART_TRANS		SIG_USART_TRANS
	#define SIG_UART_RECV		SIG_USART_RECV
	#define SIG_UART_DATA		SIG_USART_DATA
#endif
// compatibility with dual-uart processors
// (if you need to use both uarts, please use the uart2 library)
#if defined(__AVR_ATmega161__)
	#define UDR					UDR0
	#define UCR					UCSR0B
	#define UBRRL				UBRR0
	#define SIG_UART_TRANS		SIG_UART0_TRANS
	#define SIG_UART_RECV		SIG_UART0_RECV
	#define SIG_UART_DATA		SIG_UART0_DATA
#endif
#if defined(__AVR_ATmega128__)
#ifdef UART_USE_UART1
	#define UDR					UDR1
	#define UCR					UCSR1B
	#define UBRRL				UBRR1L
	#define UBRRH				UBRR1H
	#define SIG_UART_TRANS		SIG_UART1_TRANS
	#define SIG_UART_RECV		SIG_UART1_RECV
	#define SIG_UART_DATA		SIG_UART1_DATA
#else
	#define UDR					UDR0
	#define UCR					UCSR0B
	#define UBRRL				UBRR0L
	#define UBRRH				UBRR0H
	#define SIG_UART_TRANS		SIG_UART0_TRANS
	#define SIG_UART_RECV		SIG_UART0_RECV
	#define SIG_UART_DATA		SIG_UART0_DATA
#endif
#endif

// functions

//! Initializes uart.
/// \note	After running this init function, the processor
/// I/O pins that used for uart communications (RXD, TXD)
/// are no long available for general purpose I/O.
void uartInit(void);

//! Initializes transmit and receive buffers.
/// Automatically called from uartInit()
void uartInitBuffers(void);

//! Redirects received data to a user function.
///
void uartSetRxHandler(void (*rx_func)(unsigned char c));

//! Sets the uart baud rate.
/// Argument should be in bits-per-second, like \c uartSetBaudRate(9600);
void uartSetBaudRate(u32 baudrate);

//! Returns pointer to the receive buffer structure.
///
cBuffer* uartGetRxBuffer(void);

//! Returns pointer to the transmit buffer structure.
///
cBuffer* uartGetTxBuffer(void);

//! Sends a single byte over the uart.
/// \note This function waits for the uart to be ready,
/// therefore, consecutive calls to uartSendByte() will
/// go only as fast as the data can be sent over the
/// serial port.
void uartSendByte(u08 data);

//! Gets a single byte from the uart receive buffer.
/// Returns the byte, or -1 if no byte is available (getchar-style).
int uartGetByte(void);

//! Gets a single byte from the uart receive buffer.
/// Function returns TRUE if data was available, FALSE if not.
/// Actual data is returned in variable pointed to by "data".
/// Example usage:
/// \code
/// char myReceivedByte;
/// uartReceiveByte( &myReceivedByte );
/// \endcode
u08 uartReceiveByte(u08* data);

//! Returns TRUE/FALSE if receive buffer is empty/not-empty.
///
u08 uartReceiveBufferIsEmpty(void);

//! Flushes (deletes) all data from receive buffer.
///
void uartFlushReceiveBuffer(void);

//! Add byte to end of uart Tx buffer.
///	Returns TRUE if successful, FALSE if failed (no room left in buffer).
u08 uartAddToTxBuffer(u08 data);

//! Begins transmission of the transmit buffer under interrupt control.
///
void uartSendTxBuffer(void);

//! Sends a block of data via the uart using interrupt control.
/// \param buffer	pointer to data to be sent
///	\param nBytes	length of data (number of bytes to sent)
u08  uartSendBuffer(char *buffer, u16 nBytes);

#endif


