LUFA/Drivers/Peripheral/XMEGA/Serial_XMEGA.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 (XMEGA)
  33  *
  34  *  On-chip serial USART driver for the XMEGA 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_XMEGA Serial USART Peripheral Driver (XMEGA)
  42  *
  43  *  \section Sec_Serial_XMEGA_ModDescription Module Description
  44  *  On-chip serial USART driver for the XMEGA 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_XMEGA_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(&USARTD0, 9600, false);
  56  *
  57  *      // Send a string through the USART
  58  *      Serial_TxString(&USARTD0, "Test String\r\n");
  59  *
  60  *      // Receive a byte through the USART
  61  *      uint8_t DataByte = Serial_RxByte(&USARTD0);
  62  *  \endcode
  63  *
  64  *  @{
  65  */
  66
  67 #ifndef __SERIAL_XMEGA_H__
  68 #define __SERIAL_XMEGA_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,out] USART           Pointer to the base of the USART peripheral within the device.
 122                          *  \param[in]     FlashStringPtr  Pointer to a string located in program space.
 123                          */
 124                         void Serial_SendString_P(USART_t* const USART,
 125                                                  const char* FlashStringPtr) ATTR_NON_NULL_PTR_ARG(1);
 126
 127                         /** Transmits a given string located in SRAM memory through the USART.
 128                          *
 129                          *  \param[in,out] USART      Pointer to the base of the USART peripheral within the device.
 130                          *  \param[in]     StringPtr  Pointer to a string located in SRAM space.
 131                          */
 132                         void Serial_SendString(USART_t* const USART,
 133                                                const char* StringPtr) ATTR_NON_NULL_PTR_ARG(1);
 134
 135                         /** Transmits a given buffer located in SRAM memory through the USART.
 136                          *
 137                          *  \param[in,out] USART   Pointer to the base of the USART peripheral within the device.
 138                          *  \param[in]     Buffer  Pointer to a buffer containing the data to send.
 139                          *  \param[in]     Length  Length of the data to send, in bytes.
 140                          */
 141                         void Serial_SendData(USART_t* const USART,
 142                                              const void* Buffer,
 143                                              uint16_t Length) ATTR_NON_NULL_PTR_ARG(1);
 144
 145                         /** Creates a standard character stream from the USART so that it can be used with all the regular functions
 146                          *  in the avr-libc \c <stdio.h> library that accept a \c FILE stream as a destination (e.g. \c fprintf). The created
 147                          *  stream is bidirectional and can be used for both input and output functions.
 148                          *
 149                          *  Reading data from this stream is non-blocking, i.e. in most instances, complete strings cannot be read in by a single
 150                          *  fetch, as the endpoint will not be ready at some point in the transmission, aborting the transfer. However, this may
 151                          *  be used when the read data is processed byte-per-bye (via \c getc()) or when the user application will implement its own
 152                          *  line buffering.
 153                          *
 154                          *  \param[in,out] Stream  Pointer to a FILE structure where the created stream should be placed, if \c NULL, \c stdout
 155                          *                         and \c stdin will be configured to use the USART.
 156                          *
 157                          *  \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
 158                          */
 159                         void Serial_CreateStream(FILE* Stream);
 160
 161                         /** Identical to \ref Serial_CreateStream(), except that reads are blocking until the calling stream function terminates
 162                          *  the transfer.
 163                          *
 164                          *  \param[in,out] Stream  Pointer to a FILE structure where the created stream should be placed, if \c NULL, \c stdout
 165                          *                         and \c stdin will be configured to use the USART.
 166                          *
 167                          *  \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
 168                          */
 169                         void Serial_CreateBlockingStream(FILE* Stream);
 170
 171                 /* Inline Functions: */
 172                         /** Initializes the USART, ready for serial data transmission and reception. This initializes the interface to
 173                          *  standard 8-bit, no parity, 1 stop bit settings suitable for most applications.
 174                          *
 175                          *  \param[in,out] USART        Pointer to the base of the USART peripheral within the device.
 176                          *  \param[in]     BaudRate     Serial baud rate, in bits per second. This should be the target baud rate regardless of
 177                          *                              the \c DoubleSpeed parameter's value.
 178                          *  \param[in]     DoubleSpeed  Enables double speed mode when set, halving the sample time to double the baud rate.
 179                          */
 180                         static inline void Serial_Init(USART_t* const USART,
 181                                                        const uint32_t BaudRate,
 182                                                        const bool DoubleSpeed) ATTR_NON_NULL_PTR_ARG(1);
 183                         static inline void Serial_Init(USART_t* const USART,
 184                                                        const uint32_t BaudRate,
 185                                                        const bool DoubleSpeed)
 186                         {
 187                                 uint16_t BaudValue = (DoubleSpeed ? SERIAL_2X_UBBRVAL(BaudRate) : SERIAL_UBBRVAL(BaudRate));
 188
 189                                 USART->BAUDCTRLB = (BaudValue >> 8);
 190                                 USART->BAUDCTRLA = (BaudValue & 0xFF);
 191
 192                                 USART->CTRLC = (USART_CMODE_ASYNCHRONOUS_gc | USART_PMODE_DISABLED_gc | USART_CHSIZE_8BIT_gc);
 193                                 USART->CTRLB = (USART_RXEN_bm | USART_TXEN_bm | (DoubleSpeed ? USART_CLK2X_bm : 0));
 194                         }
 195
 196                         /** Turns off the USART driver, disabling and returning used hardware to their default configuration.
 197                          *
 198                          *  \param[in,out] USART  Pointer to the base of the USART peripheral within the device.
 199                          */
 200                         static inline void Serial_Disable(USART_t* const USART) ATTR_ALWAYS_INLINE ATTR_NON_NULL_PTR_ARG(1);
 201                         static inline void Serial_Disable(USART_t* const USART)
 202                         {
 203                                 USART->CTRLA = 0;
 204                                 USART->CTRLB = 0;
 205                                 USART->CTRLC = 0;
 206                         }
 207
 208                         /** Indicates whether a character has been received through the USART.
 209                          *
 210                          *  \param[in,out] USART  Pointer to the base of the USART peripheral within the device.
 211                          *
 212                          *  \return Boolean \c true if a character has been received, \c false otherwise.
 213                          */
 214                         static inline bool Serial_IsCharReceived(USART_t* const USART) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT ATTR_NON_NULL_PTR_ARG(1);
 215                         static inline bool Serial_IsCharReceived(USART_t* const USART)
 216                         {
 217                                 return ((USART->STATUS & USART_RXCIF_bm) ? true : false);
 218                         }
 219
 220                         /** Indicates whether there is hardware buffer space for a new transmit on the USART. This
 221                          *  function can be used to determine if a call to \ref Serial_SendByte() will block in advance.
 222                          *
 223                          *  \param[in,out] USART  Pointer to the base of the USART peripheral within the device.
 224                          *
 225                          *  \return Boolean \c true if a character can be queued for transmission immediately, \c false otherwise.
 226                          */
 227                         static inline bool Serial_IsSendReady(USART_t* const USART) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT ATTR_NON_NULL_PTR_ARG(1);
 228                         static inline bool Serial_IsSendReady(USART_t* const USART)
 229                         {
 230                                 return (USART->STATUS & USART_DREIF_bm) ? true : false;
 231                         }
 232
 233                         /** Indicates whether the hardware USART transmit buffer is completely empty, indicating all
 234                          *  pending transmissions have completed.
 235                          *
 236                          *  \param[in,out] USART  Pointer to the base of the USART peripheral within the device.
 237                          *
 238                          *  \return Boolean \c true if no characters are buffered for transmission, \c false otherwise.
 239                          */
 240                         static inline bool Serial_IsSendComplete(USART_t* const USART) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT ATTR_NON_NULL_PTR_ARG(1);
 241                         static inline bool Serial_IsSendComplete(USART_t* const USART)
 242                         {
 243                                 return (USART->STATUS & USART_TXCIF_bm) ? true : false;
 244                         }
 245
 246                         /** Transmits a given byte through the USART.
 247                          *
 248                          *  \note If no buffer space is available in the hardware USART, this function will block. To check if
 249                          *        space is available before calling this function, see \ref Serial_IsSendReady().
 250                          *
 251                          *  \param[in,out] USART     Pointer to the base of the USART peripheral within the device.
 252                          *  \param[in]     DataByte  Byte to transmit through the USART.
 253                          */
 254                         static inline void Serial_SendByte(USART_t* const USART,
 255                                                            const char DataByte) ATTR_ALWAYS_INLINE ATTR_NON_NULL_PTR_ARG(1);
 256                         static inline void Serial_SendByte(USART_t* const USART,
 257                                                            const char DataByte)
 258                         {
 259                                 while (!(Serial_IsSendReady(USART)));
 260                                 USART->DATA = DataByte;
 261                         }
 262
 263                         /** Receives the next byte from the USART.
 264                          *
 265                          *  \param[in,out] USART  Pointer to the base of the USART peripheral within the device.
 266                          *
 267                          *  \return Next byte received from the USART, or a negative value if no byte has been received.
 268                          */
 269                         static inline int16_t Serial_ReceiveByte(USART_t* const USART) ATTR_ALWAYS_INLINE ATTR_NON_NULL_PTR_ARG(1);
 270                         static inline int16_t Serial_ReceiveByte(USART_t* const USART)
 271                         {
 272                                 if (!(Serial_IsCharReceived(USART)))
 273                                   return -1;
 274
 275                                 USART->STATUS = USART_RXCIF_bm;
 276                                 return USART->DATA;
 277                         }
 278
 279         /* Disable C linkage for C++ Compilers: */
 280                 #if defined(__cplusplus)
 281                         }
 282                 #endif
 283
 284 #endif
 285
 286 /** @} */
 287