protocol/lufa/LUFA-git/LUFA/Drivers/Peripheral/AVR8/Serial_AVR8.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2014.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2014  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 disclaims 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_Serial_AVR8_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 USART driver
  47  *        dispatch header located in LUFA/Drivers/Peripheral/Serial.h.
  48  *
  49  *  \section Sec_Serial_AVR8_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_SendString("Test String\r\n");
  59  *
  60  *      // Send a raw byte through the USART
  61  *      Serial_SendByte(0xDC);
  62  *
  63  *      // Receive a byte through the USART (or -1 if no data received)
  64  *      int16_t DataByte = Serial_ReceiveByte();
  65  *  \endcode
  66  *
  67  *  @{
  68  */
  69
  70 #ifndef __SERIAL_AVR8_H__
  71 #define __SERIAL_AVR8_H__
  72
  73         /* Includes: */
  74                 #include "../../../Common/Common.h"
  75                 #include "../../Misc/TerminalCodes.h"
  76
  77                 #include <stdio.h>
  78
  79         /* Enable C linkage for C++ Compilers: */
  80                 #if defined(__cplusplus)
  81                         extern "C" {
  82                 #endif
  83
  84         /* Preprocessor Checks: */
  85                 #if !defined(__INCLUDE_FROM_SERIAL_H) && !defined(__INCLUDE_FROM_SERIAL_C)
  86                         #error Do not include this file directly. Include LUFA/Drivers/Peripheral/Serial.h instead.
  87                 #endif
  88
  89         /* Private Interface - For use in library only: */
  90         #if !defined(__DOXYGEN__)
  91                 /* External Variables: */
  92                         extern FILE USARTSerialStream;
  93
  94                 /* Function Prototypes: */
  95                         int Serial_putchar(char DataByte,
  96                                            FILE *Stream);
  97                         int Serial_getchar(FILE *Stream);
  98                         int Serial_getchar_Blocking(FILE *Stream);
  99         #endif
 100
 101         /* Public Interface - May be used in end-application: */
 102                 /* Macros: */
 103                         /** Macro for calculating the baud value from a given baud rate when the \c U2X (double speed) bit is
 104                          *  not set.
 105                          *
 106                          *  \param[in] Baud  Target serial UART baud rate.
 107                          *
 108                          *  \return Closest UBRR register value for the given UART frequency.
 109                          */
 110                         #define SERIAL_UBBRVAL(Baud)    ((((F_CPU / 16) + (Baud / 2)) / (Baud)) - 1)
 111
 112                         /** Macro for calculating the baud value from a given baud rate when the \c U2X (double speed) bit is
 113                          *  set.
 114                          *
 115                          *  \param[in] Baud  Target serial UART baud rate.
 116                          *
 117                          *  \return Closest UBRR register value for the given UART frequency.
 118                          */
 119                         #define SERIAL_2X_UBBRVAL(Baud) ((((F_CPU / 8) + (Baud / 2)) / (Baud)) - 1)
 120
 121                 /* Function Prototypes: */
 122                         /** Transmits a given NUL terminated string located in program space (FLASH) through the USART.
 123                          *
 124                          *  \param[in] FlashStringPtr  Pointer to a string located in program space.
 125                          */
 126                         void Serial_SendString_P(const char* FlashStringPtr) ATTR_NON_NULL_PTR_ARG(1);
 127
 128                         /** Transmits a given NUL terminated string located in SRAM memory through the USART.
 129                          *
 130                          *  \param[in] StringPtr  Pointer to a string located in SRAM space.
 131                          */
 132                         void Serial_SendString(const char* StringPtr) ATTR_NON_NULL_PTR_ARG(1);
 133
 134                         /** Transmits a given buffer located in SRAM memory through the USART.
 135                          *
 136                          *  \param[in] Buffer  Pointer to a buffer containing the data to send.
 137                          *  \param[in] Length  Length of the data to send, in bytes.
 138                          */
 139                         void Serial_SendData(const void* Buffer, uint16_t Length) ATTR_NON_NULL_PTR_ARG(1);
 140
 141                         /** Creates a standard character stream from the USART so that it can be used with all the regular functions
 142                          *  in the avr-libc \c <stdio.h> library that accept a \c FILE stream as a destination (e.g. \c fprintf). The created
 143                          *  stream is bidirectional and can be used for both input and output functions.
 144                          *
 145                          *  Reading data from this stream is non-blocking, i.e. in most instances, complete strings cannot be read in by a single
 146                          *  fetch, as the endpoint will not be ready at some point in the transmission, aborting the transfer. However, this may
 147                          *  be used when the read data is processed byte-per-bye (via \c getc()) or when the user application will implement its own
 148                          *  line buffering.
 149                          *
 150                          *  \param[in,out] Stream  Pointer to a FILE structure where the created stream should be placed, if \c NULL, \c stdout
 151                          *                         and \c stdin will be configured to use the USART.
 152                          *
 153                          *  \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
 154                          */
 155                         void Serial_CreateStream(FILE* Stream);
 156
 157                         /** Identical to \ref Serial_CreateStream(), except that reads are blocking until the calling stream function terminates
 158                          *  the transfer.
 159                          *
 160                          *  \param[in,out] Stream  Pointer to a FILE structure where the created stream should be placed, if \c NULL, \c stdout
 161                          *                         and \c stdin will be configured to use the USART.
 162                          *
 163                          *  \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
 164                          */
 165                         void Serial_CreateBlockingStream(FILE* Stream);
 166
 167                 /* Inline Functions: */
 168                         /** Initializes the USART, ready for serial data transmission and reception. This initializes the interface to
 169                          *  standard 8-bit, no parity, 1 stop bit settings suitable for most applications.
 170                          *
 171                          *  \param[in] BaudRate     Serial baud rate, in bits per second.
 172                          *  \param[in] DoubleSpeed  Enables double speed mode when set, halving the sample time to double the baud rate.
 173                          */
 174                         static inline void Serial_Init(const uint32_t BaudRate,
 175                                                        const bool DoubleSpeed);
 176                         static inline void Serial_Init(const uint32_t BaudRate,
 177                                                        const bool DoubleSpeed)
 178                         {
 179                                 UBRR1  = (DoubleSpeed ? SERIAL_2X_UBBRVAL(BaudRate) : SERIAL_UBBRVAL(BaudRate));
 180
 181                                 UCSR1C = ((1 << UCSZ11) | (1 << UCSZ10));
 182                                 UCSR1A = (DoubleSpeed ? (1 << U2X1) : 0);
 183                                 UCSR1B = ((1 << TXEN1)  | (1 << RXEN1));
 184
 185                                 DDRD  |= (1 << 3);
 186                                 PORTD |= (1 << 2);
 187                         }
 188
 189                         /** Turns off the USART driver, disabling and returning used hardware to their default configuration. */
 190                         static inline void Serial_Disable(void);
 191                         static inline void Serial_Disable(void)
 192                         {
 193                                 UCSR1B = 0;
 194                                 UCSR1A = 0;
 195                                 UCSR1C = 0;
 196
 197                                 UBRR1  = 0;
 198
 199                                 DDRD  &= ~(1 << 3);
 200                                 PORTD &= ~(1 << 2);
 201                         }
 202
 203                         /** Indicates whether a character has been received through the USART.
 204                          *
 205                          *  \return Boolean \c true if a character has been received, \c false otherwise.
 206                          */
 207                         static inline bool Serial_IsCharReceived(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
 208                         static inline bool Serial_IsCharReceived(void)
 209                         {
 210                                 return ((UCSR1A & (1 << RXC1)) ? true : false);
 211                         }
 212
 213                         /** Indicates whether there is hardware buffer space for a new transmit on the USART. This
 214                          *  function can be used to determine if a call to \ref Serial_SendByte() will block in advance.
 215                          *
 216                          *  \return Boolean \c true if a character can be queued for transmission immediately, \c false otherwise.
 217                          */
 218                         static inline bool Serial_IsSendReady(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
 219                         static inline bool Serial_IsSendReady(void)
 220                         {
 221                                 return ((UCSR1A & (1 << UDRE1)) ? true : false);
 222                         }
 223
 224                         /** Indicates whether the hardware USART transmit buffer is completely empty, indicating all
 225                          *  pending transmissions have completed.
 226                          *
 227                          *  \return Boolean \c true if no characters are buffered for transmission, \c false otherwise.
 228                          */
 229                         static inline bool Serial_IsSendComplete(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
 230                         static inline bool Serial_IsSendComplete(void)
 231                         {
 232                                 return ((UCSR1A & (1 << TXC1)) ? true : false);
 233                         }
 234
 235                         /** Transmits a given byte through the USART.
 236                          *
 237                          *  \note If no buffer space is available in the hardware USART, this function will block. To check if
 238                          *        space is available before calling this function, see \ref Serial_IsSendReady().
 239                          *
 240                          *  \param[in] DataByte  Byte to transmit through the USART.
 241                          */
 242                         static inline void Serial_SendByte(const char DataByte) ATTR_ALWAYS_INLINE;
 243                         static inline void Serial_SendByte(const char DataByte)
 244                         {
 245                                 while (!(Serial_IsSendReady()));
 246                                 UDR1 = DataByte;
 247                         }
 248
 249                         /** Receives the next byte from the USART.
 250                          *
 251                          *  \return Next byte received from the USART, or a negative value if no byte has been received.
 252                          */
 253                         static inline int16_t Serial_ReceiveByte(void) ATTR_ALWAYS_INLINE;
 254                         static inline int16_t Serial_ReceiveByte(void)
 255                         {
 256                                 if (!(Serial_IsCharReceived()))
 257                                   return -1;
 258
 259                                 return UDR1;
 260                         }
 261
 262         /* Disable C linkage for C++ Compilers: */
 263                 #if defined(__cplusplus)
 264                         }
 265                 #endif
 266
 267 #endif
 268
 269 /** @} */
 270