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 Fiddled around with by: jaseg
   7 CAUTION! THIS FILE CURRENTLY ONLY WORKS WITH ATMega328p and similar devices because
   8 only for these I was keen to change the signal names to proper interrupt vectors
   9 File:     $Id: uart.h,v 1.8.2.1 2007/07/01 11:14:38 peter Exp $
  10 Software: AVR-GCC 4.1, AVR Libc 1.4
  11 Hardware: any AVR with built-in UART, tested on AT90S8515 & ATmega8 at 4 Mhz
  12 License:  GNU General Public License
  13 Usage:    see Doxygen manual
  14
  15 LICENSE:
  16     Copyright (C) 2006 Peter Fleury
  17
  18     This program is free software; you can redistribute it and/or modify
  19     it under the terms of the GNU General Public License as published by
  20     the Free Software Foundation; either version 2 of the License, or
  21     any later version.
  22
  23     This program is distributed in the hope that it will be useful,
  24     but WITHOUT ANY WARRANTY; without even the implied warranty of
  25     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  26     GNU General Public License for more details.
  27
  28 ************************************************************************/
  29
  30 /**
  31  *  @defgroup pfleury_uart UART Library
  32  *  @code #include <uart.h> @endcode
  33  *
  34  *  @brief Interrupt UART library using the built-in UART with transmit and receive circular buffers.
  35  *
  36  *  This library can be used to transmit and receive data through the built in UART.
  37  *
  38  *  An interrupt is generated when the UART has finished transmitting or
  39  *  receiving a byte. The interrupt handling routines use circular buffers
  40  *  for buffering received and transmitted data.
  41  *
  42  *  The UART_RX_BUFFER_SIZE and UART_TX_BUFFER_SIZE constants define
  43  *  the size of the circular buffers in bytes. Note that these constants must be a power of 2.
  44  *  You may need to adapt this constants to your target and your application by adding
  45  *  CDEFS += -DUART_RX_BUFFER_SIZE=nn -DUART_RX_BUFFER_SIZE=nn to your Makefile.
  46  *
  47  *  @note Based on Atmel Application Note AVR306
  48  *  @author Peter Fleury pfleury@gmx.ch  http://jump.to/fleury
  49  */
  50
  51 /**@{*/
  52
  53
  54 #if (__GNUC__ * 100 + __GNUC_MINOR__) < 304
  55 #error "This library requires AVR-GCC 3.4 or later, update to newer AVR-GCC compiler !"
  56 #endif
  57
  58
  59 /*
  60 ** constants and macros
  61 */
  62
  63 /** @brief  UART Baudrate Expression
  64  *  @param  xtalcpu  system clock in Mhz, e.g. 4000000L for 4Mhz
  65  *  @param  baudrate baudrate in bps, e.g. 1200, 2400, 9600
  66  */
  67 #define UART_BAUD_SELECT(baudRate,xtalCpu) ((xtalCpu)/((baudRate)*16l)-1)
  68
  69 /** @brief  UART Baudrate Expression for ATmega double speed mode
  70  *  @param  xtalcpu  system clock in Mhz, e.g. 4000000L for 4Mhz
  71  *  @param  baudrate baudrate in bps, e.g. 1200, 2400, 9600
  72  */
  73 #define UART_BAUD_SELECT_DOUBLE_SPEED(baudRate,xtalCpu) (((xtalCpu)/((baudRate)*8l)-1)|0x8000)
  74
  75
  76 /** Size of the circular receive buffer, must be power of 2 */
  77 #ifndef UART_RX_BUFFER_SIZE
  78 #define UART_RX_BUFFER_SIZE 32
  79 #endif
  80 /** Size of the circular transmit buffer, must be power of 2 */
  81 #ifndef UART_TX_BUFFER_SIZE
  82 #define UART_TX_BUFFER_SIZE 32
  83 #endif
  84
  85 /* test if the size of the circular buffers fits into SRAM */
  86 #if ( (UART_RX_BUFFER_SIZE+UART_TX_BUFFER_SIZE) >= (RAMEND-0x60 ) )
  87 #error "size of UART_RX_BUFFER_SIZE + UART_TX_BUFFER_SIZE larger than size of SRAM"
  88 #endif
  89
  90 /*
  91 ** high byte error return code of uart_getc()
  92 */
  93 #define UART_FRAME_ERROR      0x0800              /* Framing Error by UART       */
  94 #define UART_OVERRUN_ERROR    0x0400              /* Overrun condition by UART   */
  95 #define UART_BUFFER_OVERFLOW  0x0200              /* receive ringbuffer overflow */
  96 #define UART_NO_DATA          0x0100              /* no receive data available   */
  97
  98
  99 /*
 100 ** function prototypes
 101 */
 102
 103 /**
 104    @brief   Initialize UART and set baudrate
 105    @param   baudrate Specify baudrate using macro UART_BAUD_SELECT()
 106    @return  none
 107 */
 108 extern void uart_init(unsigned int baudrate);
 109
 110
 111 /**
 112  *  @brief   Get received byte from ringbuffer
 113  *
 114  * Returns in the lower byte the received character and in the
 115  * higher byte the last receive error.
 116  * UART_NO_DATA is returned when no data is available.
 117  *
 118  *  @param   void
 119  *  @return  lower byte:  received byte from ringbuffer
 120  *  @return  higher byte: last receive status
 121  *           - \b 0 successfully received data from UART
 122  *           - \b UART_NO_DATA
 123  *             <br>no receive data available
 124  *           - \b UART_BUFFER_OVERFLOW
 125  *             <br>Receive ringbuffer overflow.
 126  *             We are not reading the receive buffer fast enough,
 127  *             one or more received character have been dropped
 128  *           - \b UART_OVERRUN_ERROR
 129  *             <br>Overrun condition by UART.
 130  *             A character already present in the UART UDR register was
 131  *             not read by the interrupt handler before the next character arrived,
 132  *             one or more received characters have been dropped.
 133  *           - \b UART_FRAME_ERROR
 134  *             <br>Framing Error by UART
 135  */
 136 extern unsigned int uart_getc(void);
 137
 138
 139 /**
 140  *  @brief   Put byte to ringbuffer for transmitting via UART
 141  *  @param   data byte to be transmitted
 142  *  @return  none
 143  */
 144 extern void uart_putc(unsigned char data);
 145
 146
 147 /**
 148  *  @brief   Put string to ringbuffer for transmitting via UART
 149  *
 150  *  The string is buffered by the uart library in a circular buffer
 151  *  and one character at a time is transmitted to the UART using interrupts.
 152  *  Blocks if it can not write the whole string into the circular buffer.
 153  *
 154  *  @param   s string to be transmitted
 155  *  @return  none
 156  */
 157 extern void uart_puts(const char *s );
 158
 159
 160 /**
 161  * @brief    Put string from program memory to ringbuffer for transmitting via UART.
 162  *
 163  * The string is buffered by the uart library in a circular buffer
 164  * and one character at a time is transmitted to the UART using interrupts.
 165  * Blocks if it can not write the whole string into the circular buffer.
 166  *
 167  * @param    s program memory string to be transmitted
 168  * @return   none
 169  * @see      uart_puts_P
 170  */
 171 extern void uart_puts_p(const char *s );
 172
 173 /**
 174  * @brief    Macro to automatically put a string constant into program memory
 175  */
 176 #define uart_puts_P(__s)       uart_puts_p(PSTR(__s))
 177
 178
 179
 180 /** @brief  Initialize USART1 (only available on selected ATmegas) @see uart_init */
 181 extern void uart1_init(unsigned int baudrate);
 182 /** @brief  Get received byte of USART1 from ringbuffer. (only available on selected ATmega) @see uart_getc */
 183 extern unsigned int uart1_getc(void);
 184 /** @brief  Put byte to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_putc */
 185 extern void uart1_putc(unsigned char data);
 186 /** @brief  Put string to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_puts */
 187 extern void uart1_puts(const char *s );
 188 /** @brief  Put string from program memory to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_puts_p */
 189 extern void uart1_puts_p(const char *s );
 190 /** @brief  Macro to automatically put a string constant into program memory */
 191 #define uart1_puts_P(__s)       uart1_puts_p(PSTR(__s))
 192
 193 /**@}*/
 194
 195
 196 #endif // UART_H
 197