LUFA/Drivers/Peripheral/Serial.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2011.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2011  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *  \brief Master include file for the USART peripheral driver.
  33  *
  34  *  Driver for the USART subsystem on supported USB AVRs.
  35  */
  36
  37 /** \ingroup Group_PeripheralDrivers
  38  *  @defgroup Group_Serial Serial USART Driver - LUFA/Drivers/Peripheral/Serial.h
  39  *
  40  *  \section Sec_Dependencies Module Source Dependencies
  41  *  The following files must be built with any user project that uses this module:
  42  *    - LUFA/Drivers/Peripheral/Serial.c <i>(Makefile source module name: LUFA_SRC_SERIAL)</i>
  43  *
  44  *  \section Sec_ModDescription Module Description
  45  *  Hardware serial USART driver. This module provides an easy to use driver for
  46  *  the setup of and transfer of data over the AVR's USART port.
  47  *
  48  *  \section Sec_ExampleUsage Example Usage
  49  *  The following snippet is an example of how this module may be used within a typical
  50  *  application.
  51  *
  52  *  \code
  53  *      // Initialise the serial USART driver before first use, with 9600 baud (and no double-speed mode)
  54  *      Serial_Init(9600, false);
  55  *
  56  *      // Send a string through the USART
  57  *      Serial_TxString("Test String\r\n");
  58  *
  59  *      // Receive a byte through the USART
  60  *      uint8_t DataByte = Serial_RxByte();
  61  *  \endcode
  62  *
  63  *  @{
  64  */
  65
  66 #ifndef __SERIAL_H__
  67 #define __SERIAL_H__
  68
  69         /* Includes: */
  70                 #include <avr/io.h>
  71                 #include <avr/pgmspace.h>
  72                 #include <stdbool.h>
  73                 #include <stdio.h>
  74
  75                 #include "../../Common/Common.h"
  76                 #include "../Misc/TerminalCodes.h"
  77
  78         /* Enable C linkage for C++ Compilers: */
  79                 #if defined(__cplusplus)
  80                         extern "C" {
  81                 #endif
  82
  83         /* Private Interface - For use in library only: */
  84         #if !defined(__DOXYGEN__)
  85                 /* External Variables: */
  86                         extern FILE USARTSerialStream;
  87
  88                 /* Function Prototypes: */
  89                         int Serial_putchar(char DataByte,
  90                                            FILE *Stream);
  91                         int Serial_getchar(FILE *Stream);
  92                         int Serial_getchar_Blocking(FILE *Stream);
  93         #endif
  94
  95         /* Public Interface - May be used in end-application: */
  96                 /* Macros: */
  97                         /** Macro for calculating the baud value from a given baud rate when the U2X (double speed) bit is
  98                          *  not set.
  99                          */
 100                         #define SERIAL_UBBRVAL(baud)    ((((F_CPU / 16) + (baud / 2)) / (baud)) - 1)
 101
 102                         /** Macro for calculating the baud value from a given baud rate when the U2X (double speed) bit is
 103                          *  set.
 104                          */
 105                         #define SERIAL_2X_UBBRVAL(baud) ((((F_CPU / 8) + (baud / 2)) / (baud)) - 1)
 106
 107                 /* Function Prototypes: */
 108                         /** Transmits a given string located in program space (FLASH) through the USART.
 109                          *
 110                          *  \param[in] FlashStringPtr  Pointer to a string located in program space.
 111                          */
 112                         void Serial_SendString_P(const char* FlashStringPtr) ATTR_NON_NULL_PTR_ARG(1);
 113
 114                         /** Transmits a given string located in SRAM memory through the USART.
 115                          *
 116                          *  \param[in] StringPtr  Pointer to a string located in SRAM space.
 117                          */
 118                         void Serial_SendString(const char* StringPtr) ATTR_NON_NULL_PTR_ARG(1);
 119
 120                 /* Inline Functions: */
 121                         /** Initializes the USART, ready for serial data transmission and reception. This initializes the interface to
 122                          *  standard 8-bit, no parity, 1 stop bit settings suitable for most applications.
 123                          *
 124                          *  \param[in] BaudRate     Serial baud rate, in bits per second.
 125                          *  \param[in] DoubleSpeed  Enables double speed mode when set, halving the sample time to double the baud rate.
 126                          */
 127                         static inline void Serial_Init(const uint32_t BaudRate,
 128                                                        const bool DoubleSpeed)
 129                         {
 130                                 UBRR1  = (DoubleSpeed ? SERIAL_2X_UBBRVAL(BaudRate) : SERIAL_UBBRVAL(BaudRate));
 131
 132                                 UCSR1C = ((1 << UCSZ11) | (1 << UCSZ10));
 133                                 UCSR1A = (DoubleSpeed ? (1 << U2X1) : 0);
 134                                 UCSR1B = ((1 << TXEN1)  | (1 << RXEN1));
 135
 136                                 DDRD  |= (1 << 3);
 137                                 PORTD |= (1 << 2);
 138                         }
 139
 140                         /** Turns off the USART driver, disabling and returning used hardware to their default configuration. */
 141                         static inline void Serial_ShutDown(void)
 142                         {
 143                                 UCSR1B = 0;
 144                                 UCSR1A = 0;
 145                                 UCSR1C = 0;
 146
 147                                 UBRR1  = 0;
 148
 149                                 DDRD  &= ~(1 << 3);
 150                                 PORTD &= ~(1 << 2);
 151                         }
 152
 153                         /** Creates a standard character stream from the USART so that it can be used with all the regular functions
 154                          *  in the avr-libc \c <stdio.h> library that accept a \c FILE stream as a destination (e.g. \c fprintf). The created
 155                          *  stream is bidirectional and can be used for both input and output functions.
 156                          *
 157                          *  Reading data from this stream is non-blocking, i.e. in most instances, complete strings cannot be read in by a single
 158                          *  fetch, as the endpoint will not be ready at some point in the transmission, aborting the transfer. However, this may
 159                          *  be used when the read data is processed byte-per-bye (via \c getc()) or when the user application will implement its own
 160                          *  line buffering.
 161                          *
 162                          *  \param[in,out] Stream  Pointer to a FILE structure where the created stream should be placed, if \c NULL stdio
 163                          *                         and stdin will be configured to use the USART.
 164                          *
 165                          *  \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
 166                          */
 167                         static inline void Serial_CreateStream(FILE* Stream)
 168                         {
 169                                 if (!(Stream))
 170                                 {
 171                                         Stream = &USARTSerialStream;
 172                                         stdin  = Stream;
 173                                         stdout = Stream;
 174                                 }
 175
 176                                 *Stream = (FILE)FDEV_SETUP_STREAM(Serial_putchar, Serial_getchar, _FDEV_SETUP_RW);
 177                         }
 178
 179                         /** Identical to \ref Serial_CreateStream(), except that reads are blocking until the calling stream function terminates
 180                          *  the transfer.
 181                          *
 182                          *  \param[in,out] Stream  Pointer to a FILE structure where the created stream should be placed, if \c NULL stdio
 183                          *                         and stdin will be configured to use the USART.
 184                          *
 185                          *  \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
 186                          */
 187                         static inline void Serial_CreateBlockingStream(FILE* Stream)
 188                         {
 189                                 if (!(Stream))
 190                                 {
 191                                         Stream = &USARTSerialStream;
 192                                         stdin  = Stream;
 193                                         stdout = Stream;
 194                                 }
 195
 196                                 *Stream = (FILE)FDEV_SETUP_STREAM(Serial_putchar, Serial_getchar_Blocking, _FDEV_SETUP_RW);
 197                         }
 198
 199                         /** Indicates whether a character has been received through the USART.
 200                          *
 201                          *  \return Boolean \c true if a character has been received, \c false otherwise.
 202                          */
 203                         static inline bool Serial_IsCharReceived(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
 204                         static inline bool Serial_IsCharReceived(void)
 205                         {
 206                                 return ((UCSR1A & (1 << RXC1)) ? true : false);
 207                         }
 208
 209                         /** Transmits a given byte through the USART.
 210                          *
 211                          *  \param[in] DataByte  Byte to transmit through the USART.
 212                          */
 213                         static inline void Serial_SendByte(const char DataByte) ATTR_ALWAYS_INLINE;
 214                         static inline void Serial_SendByte(const char DataByte)
 215                         {
 216                                 while (!(UCSR1A & (1 << UDRE1)));
 217                                 UDR1 = DataByte;
 218                         }
 219
 220                         /** Receives the next byte from the USART.
 221                          *
 222                          *  \return Next byte received from the USART, or a negative value if no byte has been received.
 223                          */
 224                         static inline int16_t Serial_ReceiveByte(void) ATTR_ALWAYS_INLINE;
 225                         static inline int16_t Serial_ReceiveByte(void)
 226                         {
 227                                 if (!(Serial_IsCharReceived()))
 228                                   return -1;
 229
 230                                 return UDR1;
 231                         }
 232
 233         /* Disable C linkage for C++ Compilers: */
 234                 #if defined(__cplusplus)
 235                         }
 236                 #endif
 237
 238 #endif
 239
 240 /** @} */
 241