uart.h

   1 #ifndef UART_H
   2 #define UART_H
   3 /************************************************************************
   4 Title:    Interrupt UART library with receive/transmit circular buffers
   5 Author:   Peter Fleury <pfleury@gmx.ch>   http://jump.to/fleury
   6 File:     $Id: uart.h,v 1.8.2.1 2007/07/01 11:14:38 peter Exp $
   7 Software: AVR-GCC 4.1, AVR Libc 1.4
   8 Hardware: any AVR with built-in UART, tested on AT90S8515 & ATmega8 at 4 Mhz
   9 License:  GNU General Public License
  10 Usage:    see Doxygen manual
  11
  12 LICENSE:
  13     Copyright (C) 2006 Peter Fleury
  14
  15     This program is free software; you can redistribute it and/or modify
  16     it under the terms of the GNU General Public License as published by
  17     the Free Software Foundation; either version 2 of the License, or
  18     any later version.
  19
  20     This program is distributed in the hope that it will be useful,
  21     but WITHOUT ANY WARRANTY; without even the implied warranty of
  22     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23     GNU General Public License for more details.
  24
  25 ************************************************************************/
  26
  27 /**
  28  *  @defgroup pfleury_uart UART Library
  29  *  @code #include <uart.h> @endcode
  30  *
  31  *  @brief Interrupt UART library using the built-in UART with transmit and receive circular buffers.
  32  *
  33  *  This library can be used to transmit and receive data through the built in UART.
  34  *
  35  *  An interrupt is generated when the UART has finished transmitting or
  36  *  receiving a byte. The interrupt handling routines use circular buffers
  37  *  for buffering received and transmitted data.
  38  *
  39  *  The UART_RX_BUFFER_SIZE and UART_TX_BUFFER_SIZE constants define
  40  *  the size of the circular buffers in bytes. Note that these constants must be a power of 2.
  41  *  You may need to adapt this constants to your target and your application by adding
  42  *  CDEFS += -DUART_RX_BUFFER_SIZE=nn -DUART_RX_BUFFER_SIZE=nn to your Makefile.
  43  *
  44  *  @note Based on Atmel Application Note AVR306
  45  *  @author Peter Fleury pfleury@gmx.ch  http://jump.to/fleury
  46  */
  47
  48 /**@{*/
  49
  50
  51 #if (__GNUC__ * 100 + __GNUC_MINOR__) < 304
  52 #error "This library requires AVR-GCC 3.4 or later, update to newer AVR-GCC compiler !"
  53 #endif
  54
  55
  56 /*
  57 ** constants and macros
  58 */
  59
  60 /** @brief  UART Baudrate Expression
  61  *  @param  xtalcpu  system clock in Mhz, e.g. 4000000L for 4Mhz
  62  *  @param  baudrate baudrate in bps, e.g. 1200, 2400, 9600
  63  */
  64 #define UART_BAUD_SELECT(baudRate,xtalCpu) ((xtalCpu)/((baudRate)*16l)-1)
  65
  66 /** @brief  UART Baudrate Expression for ATmega double speed mode
  67  *  @param  xtalcpu  system clock in Mhz, e.g. 4000000L for 4Mhz
  68  *  @param  baudrate baudrate in bps, e.g. 1200, 2400, 9600
  69  */
  70 #define UART_BAUD_SELECT_DOUBLE_SPEED(baudRate,xtalCpu) (((xtalCpu)/((baudRate)*8l)-1)|0x8000)
  71
  72
  73 /** Size of the circular receive buffer, must be power of 2 */
  74 #ifndef UART_RX_BUFFER_SIZE
  75 #define UART_RX_BUFFER_SIZE 32
  76 #endif
  77 /** Size of the circular transmit buffer, must be power of 2 */
  78 #ifndef UART_TX_BUFFER_SIZE
  79 #define UART_TX_BUFFER_SIZE 32
  80 #endif
  81
  82 /* test if the size of the circular buffers fits into SRAM */
  83 #if ( (UART_RX_BUFFER_SIZE+UART_TX_BUFFER_SIZE) >= (RAMEND-0x60 ) )
  84 #error "size of UART_RX_BUFFER_SIZE + UART_TX_BUFFER_SIZE larger than size of SRAM"
  85 #endif
  86
  87 /*
  88 ** high byte error return code of uart_getc()
  89 */
  90 #define UART_FRAME_ERROR      0x0800              /* Framing Error by UART       */
  91 #define UART_OVERRUN_ERROR    0x0400              /* Overrun condition by UART   */
  92 #define UART_BUFFER_OVERFLOW  0x0200              /* receive ringbuffer overflow */
  93 #define UART_NO_DATA          0x0100              /* no receive data available   */
  94
  95
  96 /*
  97 ** function prototypes
  98 */
  99
 100 /**
 101    @brief   Initialize UART and set baudrate
 102    @param   baudrate Specify baudrate using macro UART_BAUD_SELECT()
 103    @return  none
 104 */
 105 extern void uart_init(unsigned int baudrate);
 106
 107
 108 /**
 109  *  @brief   Get received byte from ringbuffer
 110  *
 111  * Returns in the lower byte the received character and in the
 112  * higher byte the last receive error.
 113  * UART_NO_DATA is returned when no data is available.
 114  *
 115  *  @param   void
 116  *  @return  lower byte:  received byte from ringbuffer
 117  *  @return  higher byte: last receive status
 118  *           - \b 0 successfully received data from UART
 119  *           - \b UART_NO_DATA
 120  *             <br>no receive data available
 121  *           - \b UART_BUFFER_OVERFLOW
 122  *             <br>Receive ringbuffer overflow.
 123  *             We are not reading the receive buffer fast enough,
 124  *             one or more received character have been dropped
 125  *           - \b UART_OVERRUN_ERROR
 126  *             <br>Overrun condition by UART.
 127  *             A character already present in the UART UDR register was
 128  *             not read by the interrupt handler before the next character arrived,
 129  *             one or more received characters have been dropped.
 130  *           - \b UART_FRAME_ERROR
 131  *             <br>Framing Error by UART
 132  */
 133 extern unsigned int uart_getc(void);
 134
 135
 136 /**
 137  *  @brief   Put byte to ringbuffer for transmitting via UART
 138  *  @param   data byte to be transmitted
 139  *  @return  none
 140  */
 141 extern void uart_putc(unsigned char data);
 142
 143
 144 /**
 145  *  @brief   Put string to ringbuffer for transmitting via UART
 146  *
 147  *  The string is buffered by the uart library in a circular buffer
 148  *  and one character at a time is transmitted to the UART using interrupts.
 149  *  Blocks if it can not write the whole string into the circular buffer.
 150  *
 151  *  @param   s string to be transmitted
 152  *  @return  none
 153  */
 154 extern void uart_puts(const char *s );
 155
 156
 157 /**
 158  * @brief    Put string from program memory to ringbuffer for transmitting via UART.
 159  *
 160  * The string is buffered by the uart library in a circular buffer
 161  * and one character at a time is transmitted to the UART using interrupts.
 162  * Blocks if it can not write the whole string into the circular buffer.
 163  *
 164  * @param    s program memory string to be transmitted
 165  * @return   none
 166  * @see      uart_puts_P
 167  */
 168 extern void uart_puts_p(const char *s );
 169
 170 /**
 171  * @brief    Macro to automatically put a string constant into program memory
 172  */
 173 #define uart_puts_P(__s)       uart_puts_p(PSTR(__s))
 174
 175
 176
 177 /** @brief  Initialize USART1 (only available on selected ATmegas) @see uart_init */
 178 extern void uart1_init(unsigned int baudrate);
 179 /** @brief  Get received byte of USART1 from ringbuffer. (only available on selected ATmega) @see uart_getc */
 180 extern unsigned int uart1_getc(void);
 181 /** @brief  Put byte to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_putc */
 182 extern void uart1_putc(unsigned char data);
 183 /** @brief  Put string to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_puts */
 184 extern void uart1_puts(const char *s );
 185 /** @brief  Put string from program memory to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_puts_p */
 186 extern void uart1_puts_p(const char *s );
 187 /** @brief  Macro to automatically put a string constant into program memory */
 188 #define uart1_puts_P(__s)       uart1_puts_p(PSTR(__s))
 189
 190 /**@}*/
 191
 192
 193 #endif // UART_H
 194