232 lines
7.7 KiB
C
232 lines
7.7 KiB
C
//
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// uart.h : UART driver with buffer support
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//
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// This library provides both buffered and unbuffered transmit and receive
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// functions for the AVR processor UART.<2E> Buffered access means that the
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// UART can transmit and receive data in the "background", while your code
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// continues executing.<2E> Also included are functions to initialize the
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// UART, set the baud rate, flush the buffers, and check buffer status.
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//
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// For full text output functionality, you may wish to use the rprintf
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// functions along with this driver.
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//
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// Most Atmel AVR-series processors contain one or more hardware UARTs
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// (aka, serial ports). UART serial ports can communicate with other
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// serial ports of the same type, like those used on PCs. In general,
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// UARTs are used to communicate with devices that are RS-232 compatible
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// (RS-232 is a certain kind of serial port).
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//
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// By far, the most common use for serial communications on AVR processors
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// is for sending information and data to a PC running a terminal program.
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// Here is an exmaple:
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// uartInit(); // initialize UART (serial port)
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// uartSetBaudRate(9600); // set UART speed to 9600 baud
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// rprintfInit(uartSendByte); // configure rprintf to use UART for output
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// rprintf("Hello World\r\n"); // send "hello world" message via serial port
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//
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// The CPU frequency (F_CPU) must be set correctly in \c global.h
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// for the UART library to calculate correct baud rates. Furthermore,
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// certain CPU frequencies will not produce exact baud rates due to
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// integer frequency division round-off. See your AVR processor's
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// datasheet for full details.
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//
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// Copyright (c) 2000-2002 Pascal Stang
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation; either version 2
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// of the License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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//
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// $Id$
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#ifndef UART_H
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#define UART_H
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#include "global.h"
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#include "buffer.h"
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//! Default uart baud rate.
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/// This is the default speed after a uartInit() command,
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/// and can be changed by using uartSetBaudRate().
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#ifndef UART_DEFAULT_BAUD_RATE
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#define UART_DEFAULT_BAUD_RATE 9600
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#endif
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// buffer memory allocation defines
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// buffer sizes
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#ifndef UART_TX_BUFFER_SIZE
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//! Number of bytes for uart transmit buffer.
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/// Do not change this value in uart.h, but rather override
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/// it with the desired value defined in your project's global.h
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#define UART_TX_BUFFER_SIZE 0x0040
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#endif
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#ifndef UART_RX_BUFFER_SIZE
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//! Number of bytes for uart receive buffer.
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/// Do not change this value in uart.h, but rather override
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/// it with the desired value defined in your project's global.h
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#define UART_RX_BUFFER_SIZE 0x0040
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#endif
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// define this key if you wish to use
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// external RAM for the UART buffers
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//#define UART_BUFFER_EXTERNAL_RAM
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#ifdef UART_BUFFER_EXTERNAL_RAM
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// absolute address of uart buffers
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#define UART_TX_BUFFER_ADDR 0x1000
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#define UART_RX_BUFFER_ADDR 0x1100
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#endif
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//! Type of interrupt handler to use for uart interrupts.
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/// Value may be SIGNAL or INTERRUPT.
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/// \warning Do not change unless you know what you're doing.
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#ifndef UART_INTERRUPT_HANDLER
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#define UART_INTERRUPT_HANDLER SIGNAL
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#endif
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// compatibility with most newer processors
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#ifdef UCSRB
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#define UCR UCSRB
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#endif
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// compatibility with old Mega processors
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#if defined(UBRR) && !defined(UBRRL)
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#define UBRRL UBRR
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#endif
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// compatibility with megaXX8 processors
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#if defined(__AVR_ATmega48__) || \
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defined(__AVR_ATmega88__) || \
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defined(__AVR_ATmega168__) || \
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defined(__AVR_ATmega644__)
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#define UDR UDR0
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#define UCR UCSR0B
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#define RXCIE RXCIE0
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#define TXCIE TXCIE0
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#define RXC RXC0
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#define TXC TXC0
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#define RXEN RXEN0
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#define TXEN TXEN0
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#define UBRRL UBRR0L
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#define UBRRH UBRR0H
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#define SIG_UART_TRANS SIG_USART_TRANS
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#define SIG_UART_RECV SIG_USART_RECV
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#define SIG_UART_DATA SIG_USART_DATA
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#endif
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// compatibility with mega169 processors
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#if defined(__AVR_ATmega169__)
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#define SIG_UART_TRANS SIG_USART_TRANS
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#define SIG_UART_RECV SIG_USART_RECV
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#define SIG_UART_DATA SIG_USART_DATA
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#endif
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// compatibility with dual-uart processors
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// (if you need to use both uarts, please use the uart2 library)
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#if defined(__AVR_ATmega161__)
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#define UDR UDR0
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#define UCR UCSR0B
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#define UBRRL UBRR0
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#define SIG_UART_TRANS SIG_UART0_TRANS
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#define SIG_UART_RECV SIG_UART0_RECV
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#define SIG_UART_DATA SIG_UART0_DATA
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#endif
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#if defined(__AVR_ATmega128__)
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#ifdef UART_USE_UART1
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#define UDR UDR1
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#define UCR UCSR1B
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#define UBRRL UBRR1L
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#define UBRRH UBRR1H
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#define SIG_UART_TRANS SIG_UART1_TRANS
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#define SIG_UART_RECV SIG_UART1_RECV
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#define SIG_UART_DATA SIG_UART1_DATA
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#else
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#define UDR UDR0
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#define UCR UCSR0B
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#define UBRRL UBRR0L
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#define UBRRH UBRR0H
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#define SIG_UART_TRANS SIG_UART0_TRANS
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#define SIG_UART_RECV SIG_UART0_RECV
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#define SIG_UART_DATA SIG_UART0_DATA
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#endif
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#endif
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// functions
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//! Initializes uart.
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/// \note After running this init function, the processor
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/// I/O pins that used for uart communications (RXD, TXD)
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/// are no long available for general purpose I/O.
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void uartInit(void);
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//! Initializes transmit and receive buffers.
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/// Automatically called from uartInit()
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void uartInitBuffers(void);
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//! Redirects received data to a user function.
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///
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void uartSetRxHandler(void (*rx_func)(unsigned char c));
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//! Sets the uart baud rate.
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/// Argument should be in bits-per-second, like \c uartSetBaudRate(9600);
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void uartSetBaudRate(u32 baudrate);
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//! Returns pointer to the receive buffer structure.
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///
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cBuffer* uartGetRxBuffer(void);
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//! Returns pointer to the transmit buffer structure.
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///
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cBuffer* uartGetTxBuffer(void);
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//! Sends a single byte over the uart.
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/// \note This function waits for the uart to be ready,
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/// therefore, consecutive calls to uartSendByte() will
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/// go only as fast as the data can be sent over the
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/// serial port.
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void uartSendByte(u08 data);
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//! Gets a single byte from the uart receive buffer.
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/// Returns the byte, or -1 if no byte is available (getchar-style).
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int uartGetByte(void);
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//! Gets a single byte from the uart receive buffer.
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/// Function returns TRUE if data was available, FALSE if not.
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/// Actual data is returned in variable pointed to by "data".
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/// Example usage:
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/// \code
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/// char myReceivedByte;
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/// uartReceiveByte( &myReceivedByte );
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/// \endcode
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u08 uartReceiveByte(u08* data);
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//! Returns TRUE/FALSE if receive buffer is empty/not-empty.
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///
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u08 uartReceiveBufferIsEmpty(void);
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//! Flushes (deletes) all data from receive buffer.
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///
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void uartFlushReceiveBuffer(void);
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//! Add byte to end of uart Tx buffer.
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/// Returns TRUE if successful, FALSE if failed (no room left in buffer).
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u08 uartAddToTxBuffer(u08 data);
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//! Begins transmission of the transmit buffer under interrupt control.
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///
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void uartSendTxBuffer(void);
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//! Sends a block of data via the uart using interrupt control.
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/// \param buffer pointer to data to be sent
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/// \param nBytes length of data (number of bytes to sent)
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u08 uartSendBuffer(char *buffer, u16 nBytes);
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#endif
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