async.h

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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 1.19 2008/11/30 10:17:31 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 };
00083 
00084 /*! Message put function for data pumps */
00085 typedef void (*put_msg_func_t)(void *user_data, const uint8_t *msg, int len);
00086 
00087 /*! Message get function for data pumps */
00088 typedef int (*get_msg_func_t)(void *user_data, uint8_t *msg, int max_len);
00089 
00090 /*! Byte put function for data pumps */
00091 typedef void (*put_byte_func_t)(void *user_data, int byte);
00092 
00093 /*! Byte get function for data pumps */
00094 typedef int (*get_byte_func_t)(void *user_data);
00095 
00096 /*! Bit put function for data pumps */
00097 typedef void (*put_bit_func_t)(void *user_data, int bit);
00098 
00099 /*! Bit get function for data pumps */
00100 typedef int (*get_bit_func_t)(void *user_data);
00101 
00102 /*! Completion callback function for tx data pumps */
00103 typedef int (*modem_tx_status_func_t)(void *user_data, int status);
00104 
00105 /*! Completion callback function for rx data pumps */
00106 typedef int (*modem_rx_status_func_t)(void *user_data, int status);
00107 
00108 enum
00109 {
00110     /*! No parity bit should be used */
00111     ASYNC_PARITY_NONE = 0,
00112     /*! An even parity bit will exist, after the data bits */
00113     ASYNC_PARITY_EVEN,
00114     /*! An odd parity bit will exist, after the data bits */
00115     ASYNC_PARITY_ODD
00116 };
00117 
00118 /*!
00119     Asynchronous data transmit descriptor. This defines the state of a single
00120     working instance of a byte to asynchronous serial converter, for use
00121     in FSK modems.
00122 */
00123 typedef struct async_tx_state_s async_tx_state_t;
00124 
00125 /*!
00126     Asynchronous data receive descriptor. This defines the state of a single
00127     working instance of an asynchronous serial to byte converter, for use
00128     in FSK modems.
00129 */
00130 typedef struct async_rx_state_s async_rx_state_t;
00131 
00132 #if defined(__cplusplus)
00133 extern "C"
00134 {
00135 #endif
00136 
00137 /*! Convert a signal status to a short text description.
00138     \brief Convert a signal status to a short text description.
00139     \param status The modem signal status.
00140     \return A pointer to the description. */
00141 const char *signal_status_to_str(int status);
00142 
00143 /*! Initialise an asynchronous data transmit context.
00144     \brief Initialise an asynchronous data transmit context.
00145     \param s The transmitter context.
00146     \param data_bits The number of data bit.
00147     \param parity_bits The type of parity.
00148     \param stop_bits The number of stop bits.
00149     \param use_v14 TRUE if V.14 rate adaption processing should be used.
00150     \param get_byte The callback routine used to get the data to be transmitted.
00151     \param user_data An opaque pointer.
00152     \return A pointer to the initialised context, or NULL if there was a problem. */
00153 async_tx_state_t *async_tx_init(async_tx_state_t *s,
00154                                 int data_bits,
00155                                 int parity_bits,
00156                                 int stop_bits,
00157                                 int use_v14,
00158                                 get_byte_func_t get_byte,
00159                                 void *user_data);
00160 
00161 /*! Get the next bit of a transmitted serial bit stream.
00162     \brief Get the next bit of a transmitted serial bit stream.
00163     \param user_data An opaque point which must point to a transmitter context.
00164     \return the next bit, or PUTBIT_END_OF_DATA to indicate the data stream has ended. */
00165 int async_tx_get_bit(void *user_data);
00166 
00167 /*! Initialise an asynchronous data receiver context.
00168     \brief Initialise an asynchronous data receiver context.
00169     \param s The receiver context.
00170     \param data_bits The number of data bits.
00171     \param parity_bits The type of parity.
00172     \param stop_bits The number of stop bits.
00173     \param use_v14 TRUE if V.14 rate adaption processing should be used.
00174     \param put_byte The callback routine used to put the received data.
00175     \param user_data An opaque pointer.
00176     \return A pointer to the initialised context, or NULL if there was a problem. */
00177 async_rx_state_t *async_rx_init(async_rx_state_t *s,
00178                                 int data_bits,
00179                                 int parity_bits,
00180                                 int stop_bits,
00181                                 int use_v14,
00182                                 put_byte_func_t put_byte,
00183                                 void *user_data);
00184 
00185 /*! Accept a bit from a received serial bit stream
00186     \brief Accept a bit from a received serial bit stream
00187     \param user_data An opaque point which must point to a receiver context.
00188     \param bit The new bit. Some special values are supported for this field.
00189         - SIG_STATUS_CARRIER_UP
00190         - SIG_STATUS_CARRIER_DOWN
00191         - SIG_STATUS_TRAINING_SUCCEEDED
00192         - SIG_STATUS_TRAINING_FAILED
00193         - SIG_STATUS_END_OF_DATA */
00194 void async_rx_put_bit(void *user_data, int bit);
00195 
00196 #if defined(__cplusplus)
00197 }
00198 #endif
00199 
00200 #endif
00201 /*- End of file ------------------------------------------------------------*/

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