spandsp  0.0.6
async.h
Go to the documentation of this file.
1 /*
2  * SpanDSP - a series of DSP components for telephony
3  *
4  * async.h - Asynchronous serial bit stream encoding and decoding
5  *
6  * Written by Steve Underwood <steveu@coppice.org>
7  *
8  * Copyright (C) 2003 Steve Underwood
9  *
10  * All rights reserved.
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU Lesser General Public License version 2.1,
14  * as published by the Free Software Foundation.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19  * GNU Lesser General Public License for more details.
20  *
21  * You should have received a copy of the GNU Lesser General Public
22  * License along with this program; if not, write to the Free Software
23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24  */
25 
26 /*! \file */
27 
28 /*! \page async_page Asynchronous bit stream processing
29 \section async_page_sec_1 What does it do?
30 The asynchronous serial bit stream processing module provides
31 generation and decoding facilities for most asynchronous data
32 formats. It supports:
33  - 1 or 2 stop bits.
34  - Odd, even or no parity.
35  - 5, 6, 7, or 8 bit characters.
36  - V.14 rate adaption.
37 The input to this module is a bit stream. This means any symbol synchronisation
38 and decoding must occur before data is fed to this module.
39 
40 \section async_page_sec_2 The transmitter
41 ???.
42 
43 \section async_page_sec_3 The receiver
44 ???.
45 */
46 
47 #if !defined(_SPANDSP_ASYNC_H_)
48 #define _SPANDSP_ASYNC_H_
49 
50 /*! Special "bit" values for the bitstream put and get functions, and the signal status functions. */
51 enum
52 {
53  /*! \brief The carrier signal has dropped. */
55  /*! \brief The carrier signal is up. This merely indicates that carrier
56  energy has been seen. It is not an indication that the carrier is either
57  valid, or of the expected type. */
59  /*! \brief The modem is training. This is an early indication that the
60  signal seems to be of the right type. This may be needed in time critical
61  applications, like T.38, to forward an early indication of what is happening
62  on the wire. */
64  /*! \brief The modem has trained, and is ready for data exchange. */
66  /*! \brief The modem has failed to train. */
68  /*! \brief Packet framing (e.g. HDLC framing) is OK. */
70  /*! \brief The data stream has ended. */
72  /*! \brief An abort signal (e.g. an HDLC abort) has been received. */
74  /*! \brief A break signal (e.g. an async break) has been received. */
76  /*! \brief A modem has completed its task, and shut down. */
78  /*! \brief Regular octet report for things like HDLC to the MTP standards. */
80  /*! \brief Notification that a modem has detected signal quality degradation. */
82  /*! \brief Notification that a modem retrain has occurred. */
84 };
85 
86 /*! Message put function for data pumps */
87 typedef void (*put_msg_func_t)(void *user_data, const uint8_t *msg, int len);
88 
89 /*! Message get function for data pumps */
90 typedef int (*get_msg_func_t)(void *user_data, uint8_t *msg, int max_len);
91 
92 /*! Byte put function for data pumps */
93 typedef void (*put_byte_func_t)(void *user_data, int byte);
94 
95 /*! Byte get function for data pumps */
96 typedef int (*get_byte_func_t)(void *user_data);
97 
98 /*! Bit put function for data pumps */
99 typedef void (*put_bit_func_t)(void *user_data, int bit);
100 
101 /*! Bit get function for data pumps */
102 typedef int (*get_bit_func_t)(void *user_data);
103 
104 /*! Completion callback function for tx data pumps */
105 typedef void (*modem_tx_status_func_t)(void *user_data, int status);
106 
107 /*! Completion callback function for rx data pumps */
108 typedef void (*modem_rx_status_func_t)(void *user_data, int status);
109 
110 enum
111 {
112  /*! No parity bit should be used */
114  /*! An even parity bit will exist, after the data bits */
116  /*! An odd parity bit will exist, after the data bits */
118 };
119 
120 /*!
121  Asynchronous data transmit descriptor. This defines the state of a single
122  working instance of a byte to asynchronous serial converter, for use
123  in FSK modems.
124 */
126 
127 /*!
128  Asynchronous data receive descriptor. This defines the state of a single
129  working instance of an asynchronous serial to byte converter, for use
130  in FSK modems.
131 */
133 
134 #if defined(__cplusplus)
135 extern "C"
136 {
137 #endif
138 
139 /*! Convert a signal status to a short text description.
140  \brief Convert a signal status to a short text description.
141  \param status The modem signal status.
142  \return A pointer to the description. */
143 SPAN_DECLARE(const char *) signal_status_to_str(int status);
144 
145 /*! Initialise an asynchronous data transmit context.
146  \brief Initialise an asynchronous data transmit context.
147  \param s The transmitter context.
148  \param data_bits The number of data bit.
149  \param parity_bits The type of parity.
150  \param stop_bits The number of stop bits.
151  \param use_v14 TRUE if V.14 rate adaption processing should be used.
152  \param get_byte The callback routine used to get the data to be transmitted.
153  \param user_data An opaque pointer.
154  \return A pointer to the initialised context, or NULL if there was a problem. */
156  int data_bits,
157  int parity_bits,
158  int stop_bits,
159  int use_v14,
160  get_byte_func_t get_byte,
161  void *user_data);
162 
163 SPAN_DECLARE(int) async_tx_release(async_tx_state_t *s);
164 
165 SPAN_DECLARE(int) async_tx_free(async_tx_state_t *s);
166 
167 /*! Get the next bit of a transmitted serial bit stream.
168  \brief Get the next bit of a transmitted serial bit stream.
169  \param user_data An opaque point which must point to a transmitter context.
170  \return the next bit, or PUTBIT_END_OF_DATA to indicate the data stream has ended. */
171 SPAN_DECLARE_NONSTD(int) async_tx_get_bit(void *user_data);
172 
173 /*! Initialise an asynchronous data receiver context.
174  \brief Initialise an asynchronous data receiver context.
175  \param s The receiver context.
176  \param data_bits The number of data bits.
177  \param parity_bits The type of parity.
178  \param stop_bits The number of stop bits.
179  \param use_v14 TRUE if V.14 rate adaption processing should be used.
180  \param put_byte The callback routine used to put the received data.
181  \param user_data An opaque pointer.
182  \return A pointer to the initialised context, or NULL if there was a problem. */
184  int data_bits,
185  int parity_bits,
186  int stop_bits,
187  int use_v14,
189  void *user_data);
190 
191 SPAN_DECLARE(int) async_rx_release(async_rx_state_t *s);
192 
193 SPAN_DECLARE(int) async_rx_free(async_rx_state_t *s);
194 
195 /*! Accept a bit from a received serial bit stream
196  \brief Accept a bit from a received serial bit stream
197  \param user_data An opaque point which must point to a receiver context.
198  \param bit The new bit. Some special values are supported for this field.
199  - SIG_STATUS_CARRIER_UP
200  - SIG_STATUS_CARRIER_DOWN
201  - SIG_STATUS_TRAINING_SUCCEEDED
202  - SIG_STATUS_TRAINING_FAILED
203  - SIG_STATUS_END_OF_DATA */
204 SPAN_DECLARE_NONSTD(void) async_rx_put_bit(void *user_data, int bit);
205 
206 #if defined(__cplusplus)
207 }
208 #endif
209 
210 #endif
211 /*- End of file ------------------------------------------------------------*/
A modem has completed its task, and shut down.
Definition: async.h:77
int(* get_byte_func_t)(void *user_data)
Definition: async.h:96
void(* put_msg_func_t)(void *user_data, const uint8_t *msg, int len)
Definition: async.h:87
SPAN_DECLARE_NONSTD(int) async_tx_get_bit(void *user_data)
Get the next bit of a transmitted serial bit stream.
The carrier signal has dropped.
Definition: async.h:54
An abort signal (e.g. an HDLC abort) has been received.
Definition: async.h:73
Notification that a modem has detected signal quality degradation.
Definition: async.h:81
void * user_data
An opaque pointer passed when calling put_byte.
Definition: private/async.h:73
const char * signal_status_to_str(int status)
Convert a signal status to a short text description.
Definition: async.c:42
Definition: async.h:117
The modem is training. This is an early indication that the signal seems to be of the right type...
Definition: async.h:63
int use_v14
TRUE if V.14 rate adaption processing should be performed.
Definition: private/async.h:69
int stop_bits
The number of stop bits per character.
Definition: private/async.h:67
Definition: async.h:113
async_tx_state_t * async_tx_init(async_tx_state_t *s, int data_bits, int parity_bits, int stop_bits, int use_v14, get_byte_func_t get_byte, void *user_data)
Initialise an asynchronous data transmit context.
Definition: async.c:202
Regular octet report for things like HDLC to the MTP standards.
Definition: async.h:79
void(* put_byte_func_t)(void *user_data, int byte)
Definition: async.h:93
void(* put_bit_func_t)(void *user_data, int bit)
Definition: async.h:99
The data stream has ended.
Definition: async.h:71
The modem has trained, and is ready for data exchange.
Definition: async.h:65
int data_bits
The number of data bits per character.
Definition: private/async.h:63
int(* get_bit_func_t)(void *user_data)
Definition: async.h:102
int(* get_msg_func_t)(void *user_data, uint8_t *msg, int max_len)
Definition: async.h:90
void(* modem_tx_status_func_t)(void *user_data, int status)
Definition: async.h:105
Definition: async.h:115
Notification that a modem retrain has occurred.
Definition: async.h:83
A break signal (e.g. an async break) has been received.
Definition: async.h:75
Definition: private/async.h:60
put_byte_func_t put_byte
A pointer to the callback routine used to handle received characters.
Definition: private/async.h:71
Definition: private/async.h:34
The modem has failed to train.
Definition: async.h:67
void(* modem_rx_status_func_t)(void *user_data, int status)
Definition: async.h:108
async_rx_state_t * async_rx_init(async_rx_state_t *s, int data_bits, int parity_bits, int stop_bits, int use_v14, put_byte_func_t put_byte, void *user_data)
Initialise an asynchronous data receiver context.
Definition: async.c:77
Packet framing (e.g. HDLC framing) is OK.
Definition: async.h:69
The carrier signal is up. This merely indicates that carrier energy has been seen. It is not an indication that the carrier is either valid, or of the expected type.
Definition: async.h:58