LUFA/Drivers/Peripheral/AVR8/Serial_AVR8.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2019.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2019  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. This should be the target baud rate regardless of the
 172                          *                          \c DoubleSpeed parameter's value.
 173                          *  \param[in] DoubleSpeed  Enables double speed mode when set, halving the sample time to double the baud rate.
 174                          */
 175                         static inline void Serial_Init(const uint32_t BaudRate,
 176                                                        const bool DoubleSpeed);
 177                         static inline void Serial_Init(const uint32_t BaudRate,
 178                                                        const bool DoubleSpeed)
 179                         {
 180                                 UBRR1  = (DoubleSpeed ? SERIAL_2X_UBBRVAL(BaudRate) : SERIAL_UBBRVAL(BaudRate));
 181
 182                                 UCSR1C = ((1 << UCSZ11) | (1 << UCSZ10));
 183                                 UCSR1A = (DoubleSpeed ? (1 << U2X1) : 0);
 184                                 UCSR1B = ((1 << TXEN1)  | (1 << RXEN1));
 185
 186                                 DDRD  |= (1 << 3);
 187                                 PORTD |= (1 << 2);
 188                         }
 189
 190                         /** Turns off the USART driver, disabling and returning used hardware to their default configuration. */
 191                         static inline void Serial_Disable(void);
 192                         static inline void Serial_Disable(void)
 193                         {
 194                                 UCSR1B = 0;
 195                                 UCSR1A = 0;
 196                                 UCSR1C = 0;
 197
 198                                 UBRR1  = 0;
 199
 200                                 DDRD  &= ~(1 << 3);
 201                                 PORTD &= ~(1 << 2);
 202                         }
 203
 204                         /** Indicates whether a character has been received through the USART.
 205                          *
 206                          *  \return Boolean \c true if a character has been received, \c false otherwise.
 207                          */
 208                         static inline bool Serial_IsCharReceived(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
 209                         static inline bool Serial_IsCharReceived(void)
 210                         {
 211                                 return ((UCSR1A & (1 << RXC1)) ? true : false);
 212                         }
 213
 214                         /** Indicates whether there is hardware buffer space for a new transmit on the USART. This
 215                          *  function can be used to determine if a call to \ref Serial_SendByte() will block in advance.
 216                          *
 217                          *  \return Boolean \c true if a character can be queued for transmission immediately, \c false otherwise.
 218                          */
 219                         static inline bool Serial_IsSendReady(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
 220                         static inline bool Serial_IsSendReady(void)
 221                         {
 222                                 return ((UCSR1A & (1 << UDRE1)) ? true : false);
 223                         }
 224
 225                         /** Indicates whether the hardware USART transmit buffer is completely empty, indicating all
 226                          *  pending transmissions have completed.
 227                          *
 228                          *  \return Boolean \c true if no characters are buffered for transmission, \c false otherwise.
 229                          */
 230                         static inline bool Serial_IsSendComplete(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
 231                         static inline bool Serial_IsSendComplete(void)
 232                         {
 233                                 return ((UCSR1A & (1 << TXC1)) ? true : false);
 234                         }
 235
 236                         /** Transmits a given byte through the USART.
 237                          *
 238                          *  \note If no buffer space is available in the hardware USART, this function will block. To check if
 239                          *        space is available before calling this function, see \ref Serial_IsSendReady().
 240                          *
 241                          *  \param[in] DataByte  Byte to transmit through the USART.
 242                          */
 243                         static inline void Serial_SendByte(const char DataByte) ATTR_ALWAYS_INLINE;
 244                         static inline void Serial_SendByte(const char DataByte)
 245                         {
 246                                 while (!(Serial_IsSendReady()));
 247                                 UDR1 = DataByte;
 248                         }
 249
 250                         /** Receives the next byte from the USART.
 251                          *
 252                          *  \return Next byte received from the USART, or a negative value if no byte has been received.
 253                          */
 254                         static inline int16_t Serial_ReceiveByte(void) ATTR_ALWAYS_INLINE;
 255                         static inline int16_t Serial_ReceiveByte(void)
 256                         {
 257                                 if (!(Serial_IsCharReceived()))
 258                                   return -1;
 259
 260                                 return UDR1;
 261                         }
 262
 263         /* Disable C linkage for C++ Compilers: */
 264                 #if defined(__cplusplus)
 265                         }
 266                 #endif
 267
 268 #endif
 269
 270 /** @} */
 271