async.h

Go to the documentation of this file.
00001 /*
00002  * SpanDSP - a series of DSP components for telephony
00003  *
00004  * async.h - Asynchronous serial bit stream encoding and decoding
00005  *
00006  * Written by Steve Underwood <steveu@coppice.org>
00007  *
00008  * Copyright (C) 2003 Steve Underwood
00009  *
00010  * All rights reserved.
00011  *
00012  * This program is free software; you can redistribute it and/or modify
00013  * it under the terms of the GNU Lesser General Public License version 2.1,
00014  * as published by the Free Software Foundation.
00015  *
00016  * This program is distributed in the hope that it will be useful,
00017  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00019  * GNU Lesser General Public License for more details.
00020  *
00021  * You should have received a copy of the GNU Lesser General Public
00022  * License along with this program; if not, write to the Free Software
00023  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00024  *
00025  * $Id: async.h,v 1.25 2009/04/23 14:12:34 steveu Exp $
00026  */
00027 
00028 /*! \file */
00029 
00030 /*! \page async_page Asynchronous bit stream processing
00031 \section async_page_sec_1 What does it do?
00032 The asynchronous serial bit stream processing module provides
00033 generation and decoding facilities for most asynchronous data
00034 formats. It supports:
00035  - 1 or 2 stop bits.
00036  - Odd, even or no parity.
00037  - 5, 6, 7, or 8 bit characters.
00038  - V.14 rate adaption.
00039 The input to this module is a bit stream. This means any symbol synchronisation
00040 and decoding must occur before data is fed to this module.
00041 
00042 \section async_page_sec_2 The transmitter
00043 ???.
00044 
00045 \section async_page_sec_3 The receiver
00046 ???.
00047 */
00048 
00049 #if !defined(_SPANDSP_ASYNC_H_)
00050 #define _SPANDSP_ASYNC_H_
00051 
00052 /*! Special "bit" values for the bitstream put and get functions, and the signal status functions. */
00053 enum
00054 {
00055     /*! \brief The carrier signal has dropped. */
00056     SIG_STATUS_CARRIER_DOWN = -1,
00057     /*! \brief The carrier signal is up. This merely indicates that carrier
00058          energy has been seen. It is not an indication that the carrier is either
00059          valid, or of the expected type. */
00060     SIG_STATUS_CARRIER_UP = -2,
00061     /*! \brief The modem is training. This is an early indication that the
00062         signal seems to be of the right type. This may be needed in time critical
00063         applications, like T.38, to forward an early indication of what is happening
00064         on the wire. */
00065     SIG_STATUS_TRAINING_IN_PROGRESS = -3,
00066     /*! \brief The modem has trained, and is ready for data exchange. */
00067     SIG_STATUS_TRAINING_SUCCEEDED = -4,
00068     /*! \brief The modem has failed to train. */
00069     SIG_STATUS_TRAINING_FAILED = -5,
00070     /*! \brief Packet framing (e.g. HDLC framing) is OK. */
00071     SIG_STATUS_FRAMING_OK = -6,
00072     /*! \brief The data stream has ended. */
00073     SIG_STATUS_END_OF_DATA = -7,
00074     /*! \brief An abort signal (e.g. an HDLC abort) has been received. */
00075     SIG_STATUS_ABORT = -8,
00076     /*! \brief A break signal (e.g. an async break) has been received. */
00077     SIG_STATUS_BREAK = -9,
00078     /*! \brief A modem has completed its task, and shut down. */
00079     SIG_STATUS_SHUTDOWN_COMPLETE = -10,
00080     /*! \brief Regular octet report for things like HDLC to the MTP standards. */
00081     SIG_STATUS_OCTET_REPORT = -11,
00082     /*! \brief Notification that a modem has detected signal quality degradation. */
00083     SIG_STATUS_POOR_SIGNAL_QUALITY = -12,
00084     /*! \brief Notification that a modem retrain has occurred. */
00085     SIG_STATUS_MODEM_RETRAIN_OCCURRED = -13
00086 };
00087 
00088 /*! Message put function for data pumps */
00089 typedef void (*put_msg_func_t)(void *user_data, const uint8_t *msg, int len);
00090 
00091 /*! Message get function for data pumps */
00092 typedef int (*get_msg_func_t)(void *user_data, uint8_t *msg, int max_len);
00093 
00094 /*! Byte put function for data pumps */
00095 typedef void (*put_byte_func_t)(void *user_data, int byte);
00096 
00097 /*! Byte get function for data pumps */
00098 typedef int (*get_byte_func_t)(void *user_data);
00099 
00100 /*! Bit put function for data pumps */
00101 typedef void (*put_bit_func_t)(void *user_data, int bit);
00102 
00103 /*! Bit get function for data pumps */
00104 typedef int (*get_bit_func_t)(void *user_data);
00105 
00106 /*! Completion callback function for tx data pumps */
00107 typedef void (*modem_tx_status_func_t)(void *user_data, int status);
00108 
00109 /*! Completion callback function for rx data pumps */
00110 typedef void (*modem_rx_status_func_t)(void *user_data, int status);
00111 
00112 enum
00113 {
00114     /*! No parity bit should be used */
00115     ASYNC_PARITY_NONE = 0,
00116     /*! An even parity bit will exist, after the data bits */
00117     ASYNC_PARITY_EVEN,
00118     /*! An odd parity bit will exist, after the data bits */
00119     ASYNC_PARITY_ODD
00120 };
00121 
00122 /*!
00123     Asynchronous data transmit descriptor. This defines the state of a single
00124     working instance of a byte to asynchronous serial converter, for use
00125     in FSK modems.
00126 */
00127 typedef struct async_tx_state_s async_tx_state_t;
00128 
00129 /*!
00130     Asynchronous data receive descriptor. This defines the state of a single
00131     working instance of an asynchronous serial to byte converter, for use
00132     in FSK modems.
00133 */
00134 typedef struct async_rx_state_s async_rx_state_t;
00135 
00136 #if defined(__cplusplus)
00137 extern "C"
00138 {
00139 #endif
00140 
00141 /*! Convert a signal status to a short text description.
00142     \brief Convert a signal status to a short text description.
00143     \param status The modem signal status.
00144     \return A pointer to the description. */
00145 SPAN_DECLARE(const char *) signal_status_to_str(int status);
00146 
00147 /*! Initialise an asynchronous data transmit context.
00148     \brief Initialise an asynchronous data transmit context.
00149     \param s The transmitter context.
00150     \param data_bits The number of data bit.
00151     \param parity_bits The type of parity.
00152     \param stop_bits The number of stop bits.
00153     \param use_v14 TRUE if V.14 rate adaption processing should be used.
00154     \param get_byte The callback routine used to get the data to be transmitted.
00155     \param user_data An opaque pointer.
00156     \return A pointer to the initialised context, or NULL if there was a problem. */
00157 SPAN_DECLARE(async_tx_state_t *) async_tx_init(async_tx_state_t *s,
00158                                                int data_bits,
00159                                                int parity_bits,
00160                                                int stop_bits,
00161                                                int use_v14,
00162                                                get_byte_func_t get_byte,
00163                                                void *user_data);
00164 
00165 SPAN_DECLARE(int) async_tx_release(async_tx_state_t *s);
00166 
00167 SPAN_DECLARE(int) async_tx_free(async_tx_state_t *s);
00168 
00169 /*! Get the next bit of a transmitted serial bit stream.
00170     \brief Get the next bit of a transmitted serial bit stream.
00171     \param user_data An opaque point which must point to a transmitter context.
00172     \return the next bit, or PUTBIT_END_OF_DATA to indicate the data stream has ended. */
00173 SPAN_DECLARE_NONSTD(int) async_tx_get_bit(void *user_data);
00174 
00175 /*! Initialise an asynchronous data receiver context.
00176     \brief Initialise an asynchronous data receiver context.
00177     \param s The receiver context.
00178     \param data_bits The number of data bits.
00179     \param parity_bits The type of parity.
00180     \param stop_bits The number of stop bits.
00181     \param use_v14 TRUE if V.14 rate adaption processing should be used.
00182     \param put_byte The callback routine used to put the received data.
00183     \param user_data An opaque pointer.
00184     \return A pointer to the initialised context, or NULL if there was a problem. */
00185 SPAN_DECLARE(async_rx_state_t *) async_rx_init(async_rx_state_t *s,
00186                                                int data_bits,
00187                                                int parity_bits,
00188                                                int stop_bits,
00189                                                int use_v14,
00190                                                put_byte_func_t put_byte,
00191                                                void *user_data);
00192 
00193 SPAN_DECLARE(int) async_rx_release(async_rx_state_t *s);
00194 
00195 SPAN_DECLARE(int) async_rx_free(async_rx_state_t *s);
00196 
00197 /*! Accept a bit from a received serial bit stream
00198     \brief Accept a bit from a received serial bit stream
00199     \param user_data An opaque point which must point to a receiver context.
00200     \param bit The new bit. Some special values are supported for this field.
00201         - SIG_STATUS_CARRIER_UP
00202         - SIG_STATUS_CARRIER_DOWN
00203         - SIG_STATUS_TRAINING_SUCCEEDED
00204         - SIG_STATUS_TRAINING_FAILED
00205         - SIG_STATUS_END_OF_DATA */
00206 SPAN_DECLARE_NONSTD(void) async_rx_put_bit(void *user_data, int bit);
00207 
00208 #if defined(__cplusplus)
00209 }
00210 #endif
00211 
00212 #endif
00213 /*- End of file ------------------------------------------------------------*/

Generated by  doxygen 1.6.2