LUFA/Drivers/Peripheral/Serial.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2010  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 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  *  <b>Example Usage:</b>
  49  *  \code
  50  *      // Initialise the serial USART driver before first use, with 9600 baud (and no double-speed mode)
  51  *      Serial_Init(9600, false);
  52  *
  53  *      // Send a string through the USART
  54  *      Serial_TxString("Test String\r\n");
  55  *
  56  *      // Receive a byte through the USART
  57  *      uint8_t DataByte = Serial_RxByte();
  58  *  \endcode
  59  *
  60  *  @{
  61  */
  62
  63 #ifndef __SERIAL_H__
  64 #define __SERIAL_H__
  65
  66         /* Includes: */
  67                 #include <avr/io.h>
  68                 #include <avr/pgmspace.h>
  69                 #include <stdbool.h>
  70
  71                 #include "../../Common/Common.h"
  72                 #include "../Misc/TerminalCodes.h"
  73
  74         /* Enable C linkage for C++ Compilers: */
  75                 #if defined(__cplusplus)
  76                         extern "C" {
  77                 #endif
  78
  79         /* Public Interface - May be used in end-application: */
  80                 /* Macros: */
  81                         /** Macro for calculating the baud value from a given baud rate when the U2X (double speed) bit is
  82                          *  not set.
  83                          */
  84                         #define SERIAL_UBBRVAL(baud)    ((((F_CPU / 16) + (baud / 2)) / (baud)) - 1)
  85
  86                         /** Macro for calculating the baud value from a given baud rate when the U2X (double speed) bit is
  87                          *  set.
  88                          */
  89                         #define SERIAL_2X_UBBRVAL(baud) ((((F_CPU / 8) + (baud / 2)) / (baud)) - 1)
  90
  91                 /* Function Prototypes: */
  92                         /** Transmits a given string located in program space (FLASH) through the USART.
  93                          *
  94                          *  \param[in] FlashStringPtr  Pointer to a string located in program space.
  95                          */
  96                         void Serial_TxString_P(const char* FlashStringPtr) ATTR_NON_NULL_PTR_ARG(1);
  97
  98                         /** Transmits a given string located in SRAM memory through the USART.
  99                          *
 100                          *  \param[in] StringPtr  Pointer to a string located in SRAM space.
 101                          */
 102                         void Serial_TxString(const char* StringPtr) ATTR_NON_NULL_PTR_ARG(1);
 103
 104                 /* Inline Functions: */
 105                         /** Initializes the USART, ready for serial data transmission and reception. This initializes the interface to
 106                          *  standard 8-bit, no parity, 1 stop bit settings suitable for most applications.
 107                          *
 108                          *  \param[in] BaudRate     Serial baud rate, in bits per second.
 109                          *  \param[in] DoubleSpeed  Enables double speed mode when set, halving the sample time to double the baud rate.
 110                          */
 111                         static inline void Serial_Init(const uint32_t BaudRate,
 112                                                        const bool DoubleSpeed)
 113                         {
 114                                 UBRR1  = (DoubleSpeed ? SERIAL_2X_UBBRVAL(BaudRate) : SERIAL_UBBRVAL(BaudRate));
 115
 116                                 UCSR1C = ((1 << UCSZ11) | (1 << UCSZ10));
 117                                 UCSR1A = (DoubleSpeed ? (1 << U2X1) : 0);
 118                                 UCSR1B = ((1 << TXEN1)  | (1 << RXEN1));
 119
 120                                 DDRD  |= (1 << 3);
 121                                 PORTD |= (1 << 2);
 122                         }
 123
 124                         /** Turns off the USART driver, disabling and returning used hardware to their default configuration. */
 125                         static inline void Serial_ShutDown(void)
 126                         {
 127                                 UCSR1B = 0;
 128                                 UCSR1A = 0;
 129                                 UCSR1C = 0;
 130
 131                                 UBRR1  = 0;
 132
 133                                 DDRD  &= ~(1 << 3);
 134                                 PORTD &= ~(1 << 2);
 135                         }
 136
 137                         /** Indicates whether a character has been received through the USART.
 138                          *
 139                          *  \return Boolean true if a character has been received, false otherwise.
 140                          */
 141                         static inline bool Serial_IsCharReceived(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
 142                         static inline bool Serial_IsCharReceived(void)
 143                         {
 144                                 return ((UCSR1A & (1 << RXC1)) ? true : false);
 145                         }
 146
 147                         /** Transmits a given byte through the USART.
 148                          *
 149                          *  \param[in] DataByte  Byte to transmit through the USART.
 150                          */
 151                         static inline void Serial_TxByte(const char DataByte) ATTR_ALWAYS_INLINE;
 152                         static inline void Serial_TxByte(const char DataByte)
 153                         {
 154                                 while (!(UCSR1A & (1 << UDRE1)));
 155                                 UDR1 = DataByte;
 156                         }
 157
 158                         /** Receives a byte from the USART. This function blocks until a byte has been
 159                          *  received; if non-blocking behaviour is required, test for a received character
 160                          *  beforehand with \ref Serial_IsCharReceived().
 161                          *
 162                          *  \return Byte received from the USART.
 163                          */
 164                         static inline char Serial_RxByte(void) ATTR_ALWAYS_INLINE;
 165                         static inline char Serial_RxByte(void)
 166                         {
 167                                 while (!(UCSR1A & (1 << RXC1)));
 168                                 return UDR1;
 169                         }
 170
 171         /* Disable C linkage for C++ Compilers: */
 172                 #if defined(__cplusplus)
 173                         }
 174                 #endif
 175
 176 #endif
 177
 178 /** @} */
 179