181 lines
6.2 KiB
C
181 lines
6.2 KiB
C
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#ifndef UART_H
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#define UART_H
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/************************************************************************
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Title: Interrupt UART library with receive/transmit circular buffers
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Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
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File: $Id: uart.h,v 1.12 2012/11/19 19:52:27 peter Exp $
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Software: AVR-GCC 4.1, AVR Libc 1.4
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Hardware: any AVR with built-in UART, tested on AT90S8515 & ATmega8 at 4 Mhz
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License: GNU General Public License
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Usage: see Doxygen manual
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LICENSE:
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Copyright (C) 2006 Peter Fleury
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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any later version.
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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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/**
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* @defgroup pfleury_uart UART Library
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* @code #include <uart.h> @endcode
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*
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* @brief Interrupt UART library using the built-in UART with transmit and receive circular buffers.
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*
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* This library can be used to transmit and receive data through the built in UART.
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*
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* An interrupt is generated when the UART has finished transmitting or
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* receiving a byte. The interrupt handling routines use circular buffers
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* for buffering received and transmitted data.
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*
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* The UART_RX_BUFFER_SIZE and UART_TX_BUFFER_SIZE constants define
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* the size of the circular buffers in bytes. Note that these constants must be a power of 2.
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* You may need to adapt this constants to your target and your application by adding
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* CDEFS += -DUART_RX_BUFFER_SIZE=nn -DUART_RX_BUFFER_SIZE=nn to your Makefile.
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*
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* @note Based on Atmel Application Note AVR306
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* @author Peter Fleury pfleury@gmx.ch http://jump.to/fleury
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*/
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/**@{*/
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#if (__GNUC__ * 100 + __GNUC_MINOR__) < 304
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#error "This library requires AVR-GCC 3.4 or later, update to newer AVR-GCC compiler !"
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#endif
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/*
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** constants and macros
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*/
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/** @brief UART Baudrate Expression
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* @param xtalcpu system clock in Mhz, e.g. 4000000UL for 4Mhz
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* @param baudrate baudrate in bps, e.g. 1200, 2400, 9600
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*/
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#define UART_BAUD_SELECT(baudRate,xtalCpu) (((xtalCpu) + 8UL * (baudRate)) / (16UL * (baudRate)) -1UL)
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/** @brief UART Baudrate Expression for ATmega double speed mode
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* @param xtalcpu system clock in Mhz, e.g. 4000000UL for 4Mhz
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* @param baudrate baudrate in bps, e.g. 1200, 2400, 9600
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*/
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#define UART_BAUD_SELECT_DOUBLE_SPEED(baudRate,xtalCpu) ( ((((xtalCpu) + 4UL * (baudRate)) / (8UL * (baudRate)) -1UL)) | 0x8000)
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/** Size of the circular receive buffer, must be power of 2 */
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#ifndef UART_RX_BUFFER_SIZE
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#define UART_RX_BUFFER_SIZE 32
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#endif
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/** Size of the circular transmit buffer, must be power of 2 */
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#ifndef UART_TX_BUFFER_SIZE
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#define UART_TX_BUFFER_SIZE 32
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#endif
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/* test if the size of the circular buffers fits into SRAM */
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#if ( (UART_RX_BUFFER_SIZE+UART_TX_BUFFER_SIZE) >= (RAMEND-0x60 ) )
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#error "size of UART_RX_BUFFER_SIZE + UART_TX_BUFFER_SIZE larger than size of SRAM"
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#endif
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/*
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** high byte error return code of uart_getc()
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*/
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#define UART_FRAME_ERROR 0x1000 /* Framing Error by UART */
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#define UART_OVERRUN_ERROR 0x0800 /* Overrun condition by UART */
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#define UART_PARITY_ERROR 0x0400 /* Parity Error by UART */
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#define UART_BUFFER_OVERFLOW 0x0200 /* receive ringbuffer overflow */
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#define UART_NO_DATA 0x0100 /* no receive data available */
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/*
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** function prototypes
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*/
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/**
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@brief Initialize UART and set baudrate
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@param baudrate Specify baudrate using macro UART_BAUD_SELECT()
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@return none
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*/
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extern void uart_init(unsigned int baudrate);
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/**
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* @brief Get received byte from ringbuffer
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*
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* Returns in the lower byte the received character and in the
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* higher byte the last receive error.
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* UART_NO_DATA is returned when no data is available.
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*
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* @param void
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* @return lower byte: received byte from ringbuffer
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* @return higher byte: last receive status
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* - \b 0 successfully received data from UART
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* - \b UART_NO_DATA
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* <br>no receive data available
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* - \b UART_BUFFER_OVERFLOW
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* <br>Receive ringbuffer overflow.
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* We are not reading the receive buffer fast enough,
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* one or more received character have been dropped
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* - \b UART_OVERRUN_ERROR
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* <br>Overrun condition by UART.
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* A character already present in the UART UDR register was
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* not read by the interrupt handler before the next character arrived,
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* one or more received characters have been dropped.
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* - \b UART_FRAME_ERROR
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* <br>Framing Error by UART
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*/
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extern unsigned int uart_getc(void);
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/**
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* @brief Put byte to ringbuffer for transmitting via UART
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* @param data byte to be transmitted
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* @return none
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*/
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extern void uart_putc(unsigned char data);
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/**
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* @brief Put string to ringbuffer for transmitting via UART
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*
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* The string is buffered by the uart library in a circular buffer
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* and one character at a time is transmitted to the UART using interrupts.
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* Blocks if it can not write the whole string into the circular buffer.
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*
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* @param s string to be transmitted
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* @return none
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*/
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extern void uart_puts(const char *s );
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/**
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* @brief Put string from program memory to ringbuffer for transmitting via UART.
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*
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* The string is buffered by the uart library in a circular buffer
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* and one character at a time is transmitted to the UART using interrupts.
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* Blocks if it can not write the whole string into the circular buffer.
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*
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* @param s program memory string to be transmitted
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* @return none
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* @see uart_puts_P
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*/
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extern void uart_puts_p(const char *s );
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/**
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* @brief Macro to automatically put a string constant into program memory
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*/
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#define uart_puts_P(__s) uart_puts_p(PSTR(__s))
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#endif // UART_H
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