LUFA/Drivers/Peripheral/XMEGA/Serial_XMEGA.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2012.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2012  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 (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_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_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 uint8_t* Buffer, uint16_t Length) ATTR_NON_NULL_PTR_ARG(1);
 143
 144                         /** Creates a standard character stream from the USART so that it can be used with all the regular functions
 145                          *  in the avr-libc \c <stdio.h> library that accept a \c FILE stream as a destination (e.g. \c fprintf). The created
 146                          *  stream is bidirectional and can be used for both input and output functions.
 147                          *
 148                          *  Reading data from this stream is non-blocking, i.e. in most instances, complete strings cannot be read in by a single
 149                          *  fetch, as the endpoint will not be ready at some point in the transmission, aborting the transfer. However, this may
 150                          *  be used when the read data is processed byte-per-bye (via \c getc()) or when the user application will implement its own
 151                          *  line buffering.
 152                          *
 153                          *  \param[in,out] Stream  Pointer to a FILE structure where the created stream should be placed, if \c NULL, \c stdout
 154                          *                         and \c stdin will be configured to use the USART.
 155                          *
 156                          *  \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
 157                          */
 158                         void Serial_CreateStream(FILE* Stream);
 159
 160                         /** Identical to \ref Serial_CreateStream(), except that reads are blocking until the calling stream function terminates
 161                          *  the transfer.
 162                          *
 163                          *  \param[in,out] Stream  Pointer to a FILE structure where the created stream should be placed, if \c NULL, \c stdout
 164                          *                         and \c stdin will be configured to use the USART.
 165                          *
 166                          *  \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
 167                          */
 168                         void Serial_CreateBlockingStream(FILE* Stream);
 169
 170                 /* Inline Functions: */
 171                         /** Initializes the USART, ready for serial data transmission and reception. This initializes the interface to
 172                          *  standard 8-bit, no parity, 1 stop bit settings suitable for most applications.
 173                          *
 174                          *  \param[in,out] USART        Pointer to the base of the USART peripheral within the device.
 175                          *  \param[in]     BaudRate     Serial baud rate, in bits per second.
 176                          *  \param[in]     DoubleSpeed  Enables double speed mode when set, halving the sample time to double the baud rate.
 177                          */
 178                         static inline void Serial_Init(USART_t* const USART,
 179                                                        const uint32_t BaudRate,
 180                                                        const bool DoubleSpeed)
 181                         {
 182                                 uint16_t BaudValue = (DoubleSpeed ? SERIAL_2X_UBBRVAL(BaudRate) : SERIAL_UBBRVAL(BaudRate));
 183
 184                                 USART->BAUDCTRLB = (BaudValue >> 8);
 185                                 USART->BAUDCTRLA = (BaudValue & 0xFF);
 186
 187                                 USART->CTRLC = (USART_CMODE_ASYNCHRONOUS_gc | USART_PMODE_DISABLED_gc | USART_CHSIZE_8BIT_gc);
 188                                 USART->CTRLB = (USART_RXEN_bm | USART_TXEN_bm | (DoubleSpeed ? USART_CLK2X_bm : 0));
 189                         }
 190
 191                         /** Turns off the USART driver, disabling and returning used hardware to their default configuration.
 192                          *
 193                          *  \param[in,out] USART  Pointer to the base of the USART peripheral within the device.
 194                          */
 195                         static inline void Serial_Disable(USART_t* const USART)
 196                         {
 197                                 USART->CTRLA = 0;
 198                                 USART->CTRLB = 0;
 199                                 USART->CTRLC = 0;
 200                         }
 201
 202                         /** Indicates whether a character has been received through the USART.
 203                          *
 204                          *  \param[in,out] USART  Pointer to the base of the USART peripheral within the device.
 205                          *
 206                          *  \return Boolean \c true if a character has been received, \c false otherwise.
 207                          */
 208                         static inline bool Serial_IsCharReceived(USART_t* const USART) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
 209                         static inline bool Serial_IsCharReceived(USART_t* const USART)
 210                         {
 211                                 return ((USART->STATUS & USART_RXCIF_bm) ? true : false);
 212                         }
 213
 214                         /** Transmits a given byte through the USART.
 215                          *
 216                          *  \param[in,out] USART     Pointer to the base of the USART peripheral within the device.
 217                          *  \param[in]     DataByte  Byte to transmit through the USART.
 218                          */
 219                         static inline void Serial_SendByte(USART_t* const USART,
 220                                                            const char DataByte) ATTR_ALWAYS_INLINE;
 221                         static inline void Serial_SendByte(USART_t* const USART,
 222                                                            const char DataByte)
 223                         {
 224                                 while (!(USART->STATUS & USART_DREIF_bm));
 225                                 USART->DATA = DataByte;
 226                         }
 227
 228                         /** Receives the next byte from the USART.
 229                          *
 230                          *  \param[in,out] USART  Pointer to the base of the USART peripheral within the device.
 231                          *
 232                          *  \return Next byte received from the USART, or a negative value if no byte has been received.
 233                          */
 234                         static inline int16_t Serial_ReceiveByte(USART_t* const USART) ATTR_ALWAYS_INLINE;
 235                         static inline int16_t Serial_ReceiveByte(USART_t* const USART)
 236                         {
 237                                 if (!(Serial_IsCharReceived(USART)))
 238                                   return -1;
 239
 240                                 USART->STATUS = USART_RXCIF_bm;
 241                                 return USART->DATA;
 242                         }
 243
 244         /* Disable C linkage for C++ Compilers: */
 245                 #if defined(__cplusplus)
 246                         }
 247                 #endif
 248
 249 #endif
 250
 251 /** @} */
 252