LUFA/Drivers/Peripheral/AVR8/Serial_AVR8.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 Serial USART Peripheral Driver (AVR8)
  33  *
  34  *  On-chip serial USART driver for the 8-bit AVR microcontrollers.
  35  *
  36  *  \note This file should not be included directly. It is automatically included as needed by the USART driver
  37  *        dispatch header located in LUFA/Drivers/Peripheral/Serial.h.
  38  */
  39
  40 /** \ingroup Group_Serial
  41  *  \defgroup Group_Serial_AVR8 Serial USART Peripheral Driver (AVR8)
  42  *
  43  *  \section Sec_ModDescription Module Description
  44  *  On-chip serial USART driver for the 8-bit AVR microcontrollers.
  45  *
  46  *  \note This file should not be included directly. It is automatically included as needed by the ADC driver
  47  *        dispatch header located in LUFA/Drivers/Peripheral/Serial.h.
  48  *
  49  *  \section Sec_ExampleUsage Example Usage
  50  *  The following snippet is an example of how this module may be used within a typical
  51  *  application.
  52  *
  53  *  \code
  54  *      // Initialize the serial USART driver before first use, with 9600 baud (and no double-speed mode)
  55  *      Serial_Init(9600, false);
  56  *
  57  *      // Send a string through the USART
  58  *      Serial_TxString("Test String\r\n");
  59  *
  60  *      // Receive a byte through the USART
  61  *      uint8_t DataByte = Serial_RxByte();
  62  *  \endcode
  63  *
  64  *  @{
  65  */
  66
  67 #ifndef __SERIAL_AVR8_H__
  68 #define __SERIAL_AVR8_H__
  69
  70         /* Includes: */
  71                 #include "../../../Common/Common.h"
  72                 #include "../../Misc/TerminalCodes.h"
  73
  74                 #include <stdio.h>
  75
  76         /* Enable C linkage for C++ Compilers: */
  77                 #if defined(__cplusplus)
  78                         extern "C" {
  79                 #endif
  80
  81         /* Preprocessor Checks: */
  82                 #if !defined(__INCLUDE_FROM_SERIAL_H) && !defined(__INCLUDE_FROM_SERIAL_C)
  83                         #error Do not include this file directly. Include LUFA/Drivers/Peripheral/Serial.h instead.
  84                 #endif
  85
  86         /* Private Interface - For use in library only: */
  87         #if !defined(__DOXYGEN__)
  88                 /* External Variables: */
  89                         extern FILE USARTSerialStream;
  90
  91                 /* Function Prototypes: */
  92                         int Serial_putchar(char DataByte,
  93                                            FILE *Stream);
  94                         int Serial_getchar(FILE *Stream);
  95                         int Serial_getchar_Blocking(FILE *Stream);
  96         #endif
  97
  98         /* Public Interface - May be used in end-application: */
  99                 /* Macros: */
 100                         /** Macro for calculating the baud value from a given baud rate when the \c U2X (double speed) bit is
 101                          *  not set.
 102                          *
 103                          *  \param[in] Baud  Target serial UART baud rate.
 104                          *
 105                          *  \return Closest UBRR register value for the given UART frequency.
 106                          */
 107                         #define SERIAL_UBBRVAL(Baud)    ((((F_CPU / 16) + (Baud / 2)) / (Baud)) - 1)
 108
 109                         /** Macro for calculating the baud value from a given baud rate when the \c U2X (double speed) bit is
 110                          *  set.
 111                          *
 112                          *  \param[in] Baud  Target serial UART baud rate.
 113                          *
 114                          *  \return Closest UBRR register value for the given UART frequency.
 115                          */
 116                         #define SERIAL_2X_UBBRVAL(Baud) ((((F_CPU / 8) + (Baud / 2)) / (Baud)) - 1)
 117
 118                 /* Function Prototypes: */
 119                         /** Transmits a given string located in program space (FLASH) through the USART.
 120                          *
 121                          *  \param[in] FlashStringPtr  Pointer to a string located in program space.
 122                          */
 123                         void Serial_SendString_P(const char* FlashStringPtr) ATTR_NON_NULL_PTR_ARG(1);
 124
 125                         /** Transmits a given string located in SRAM memory through the USART.
 126                          *
 127                          *  \param[in] StringPtr  Pointer to a string located in SRAM space.
 128                          */
 129                         void Serial_SendString(const char* StringPtr) ATTR_NON_NULL_PTR_ARG(1);
 130
 131                         /** Transmits a given buffer located in SRAM memory through the USART.
 132                          *
 133                          *  \param[in] Buffer  Pointer to a buffer containing the data to send.
 134                          *  \param[in] Length  Length of the data to send, in bytes.
 135                          */
 136                         void Serial_SendData(const uint8_t* Buffer, uint16_t Length) ATTR_NON_NULL_PTR_ARG(1);
 137
 138                 /* Inline Functions: */
 139                         /** Initializes the USART, ready for serial data transmission and reception. This initializes the interface to
 140                          *  standard 8-bit, no parity, 1 stop bit settings suitable for most applications.
 141                          *
 142                          *  \param[in] BaudRate     Serial baud rate, in bits per second.
 143                          *  \param[in] DoubleSpeed  Enables double speed mode when set, halving the sample time to double the baud rate.
 144                          */
 145                         static inline void Serial_Init(const uint32_t BaudRate,
 146                                                        const bool DoubleSpeed)
 147                         {
 148                                 UBRR1  = (DoubleSpeed ? SERIAL_2X_UBBRVAL(BaudRate) : SERIAL_UBBRVAL(BaudRate));
 149
 150                                 UCSR1C = ((1 << UCSZ11) | (1 << UCSZ10));
 151                                 UCSR1A = (DoubleSpeed ? (1 << U2X1) : 0);
 152                                 UCSR1B = ((1 << TXEN1)  | (1 << RXEN1));
 153
 154                                 DDRD  |= (1 << 3);
 155                                 PORTD |= (1 << 2);
 156                         }
 157
 158                         /** Turns off the USART driver, disabling and returning used hardware to their default configuration. */
 159                         static inline void Serial_Disable(void)
 160                         {
 161                                 UCSR1B = 0;
 162                                 UCSR1A = 0;
 163                                 UCSR1C = 0;
 164
 165                                 UBRR1  = 0;
 166
 167                                 DDRD  &= ~(1 << 3);
 168                                 PORTD &= ~(1 << 2);
 169                         }
 170
 171                         /** Creates a standard character stream from the USART so that it can be used with all the regular functions
 172                          *  in the avr-libc \c <stdio.h> library that accept a \c FILE stream as a destination (e.g. \c fprintf). The created
 173                          *  stream is bidirectional and can be used for both input and output functions.
 174                          *
 175                          *  Reading data from this stream is non-blocking, i.e. in most instances, complete strings cannot be read in by a single
 176                          *  fetch, as the endpoint will not be ready at some point in the transmission, aborting the transfer. However, this may
 177                          *  be used when the read data is processed byte-per-bye (via \c getc()) or when the user application will implement its own
 178                          *  line buffering.
 179                          *
 180                          *  \param[in,out] Stream  Pointer to a FILE structure where the created stream should be placed, if \c NULL, \c stdout
 181                          *                         and \c stdin will be configured to use the USART.
 182                          *
 183                          *  \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
 184                          */
 185                         static inline void Serial_CreateStream(FILE* Stream)
 186                         {
 187                                 if (!(Stream))
 188                                 {
 189                                         Stream = &USARTSerialStream;
 190                                         stdin  = Stream;
 191                                         stdout = Stream;
 192                                 }
 193
 194                                 *Stream = (FILE)FDEV_SETUP_STREAM(Serial_putchar, Serial_getchar, _FDEV_SETUP_RW);
 195                         }
 196
 197                         /** Identical to \ref Serial_CreateStream(), except that reads are blocking until the calling stream function terminates
 198                          *  the transfer.
 199                          *
 200                          *  \param[in,out] Stream  Pointer to a FILE structure where the created stream should be placed, if \c NULL, \c stdout
 201                          *                         and \c stdin will be configured to use the USART.
 202                          *
 203                          *  \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
 204                          */
 205                         static inline void Serial_CreateBlockingStream(FILE* Stream)
 206                         {
 207                                 if (!(Stream))
 208                                 {
 209                                         Stream = &USARTSerialStream;
 210                                         stdin  = Stream;
 211                                         stdout = Stream;
 212                                 }
 213
 214                                 *Stream = (FILE)FDEV_SETUP_STREAM(Serial_putchar, Serial_getchar_Blocking, _FDEV_SETUP_RW);
 215                         }
 216
 217                         /** Indicates whether a character has been received through the USART.
 218                          *
 219                          *  \return Boolean \c true if a character has been received, \c false otherwise.
 220                          */
 221                         static inline bool Serial_IsCharReceived(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
 222                         static inline bool Serial_IsCharReceived(void)
 223                         {
 224                                 return ((UCSR1A & (1 << RXC1)) ? true : false);
 225                         }
 226
 227                         /** Transmits a given byte through the USART.
 228                          *
 229                          *  \param[in] DataByte  Byte to transmit through the USART.
 230                          */
 231                         static inline void Serial_SendByte(const char DataByte) ATTR_ALWAYS_INLINE;
 232                         static inline void Serial_SendByte(const char DataByte)
 233                         {
 234                                 while (!(UCSR1A & (1 << UDRE1)));
 235                                 UDR1 = DataByte;
 236                         }
 237
 238                         /** Receives the next byte from the USART.
 239                          *
 240                          *  \return Next byte received from the USART, or a negative value if no byte has been received.
 241                          */
 242                         static inline int16_t Serial_ReceiveByte(void) ATTR_ALWAYS_INLINE;
 243                         static inline int16_t Serial_ReceiveByte(void)
 244                         {
 245                                 if (!(Serial_IsCharReceived()))
 246                                   return -1;
 247
 248                                 return UDR1;
 249                         }
 250
 251         /* Disable C linkage for C++ Compilers: */
 252                 #if defined(__cplusplus)
 253                         }
 254                 #endif
 255
 256 #endif
 257
 258 /** @} */
 259