spandsp  3.0.0
async.h
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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  /*! \brief The link protocol (e.g. V.42) has connected. */
86  /*! \brief The link protocol (e.g. V.42) has disconnected. */
88  /*! \brief An error has occurred in the link protocol (e.g. V.42). */
90  /*! \brief Keep the link in an idle state, as there is nothing to send. */
92 };
93 
94 /*! Message put function for data pumps */
95 typedef void (*put_msg_func_t)(void *user_data, const uint8_t *msg, int len);
96 
97 /*! Message get function for data pumps */
98 typedef int (*get_msg_func_t)(void *user_data, uint8_t *msg, int max_len);
99 
100 /*! Byte put function for data pumps */
101 typedef void (*put_byte_func_t)(void *user_data, int byte);
102 
103 /*! Byte get function for data pumps */
104 typedef int (*get_byte_func_t)(void *user_data);
105 
106 /*! Bit put function for data pumps */
107 typedef void (*put_bit_func_t)(void *user_data, int bit);
108 
109 /*! Bit get function for data pumps */
110 typedef int (*get_bit_func_t)(void *user_data);
111 
112 /*! Status change callback function for data pumps */
113 typedef void (*modem_status_func_t)(void *user_data, int status);
114 
115 /*!
116  Asynchronous data transmit descriptor. This defines the state of a single
117  working instance of a byte to asynchronous serial converter, for use
118  in FSK modems.
119 */
120 typedef struct async_tx_state_s async_tx_state_t;
121 
122 /*!
123  Asynchronous data receive descriptor. This defines the state of a single
124  working instance of an asynchronous serial to byte converter, for use
125  in FSK modems.
126 */
127 typedef struct async_rx_state_s async_rx_state_t;
128 
129 enum
130 {
131  /*! No parity bit should be used */
133  /*! An even parity bit will exist, after the data bits */
135  /*! An odd parity bit will exist, after the data bits */
137 };
138 
139 #if defined(__cplusplus)
140 extern "C"
141 {
142 #endif
143 
144 /*! Convert a signal status to a short text description.
145  \brief Convert a signal status to a short text description.
146  \param status The modem signal status.
147  \return A pointer to the description. */
148 SPAN_DECLARE(const char *) signal_status_to_str(int status);
149 
150 /*! Accept a bit from a received serial bit stream
151  \brief Accept a bit from a received serial bit stream
152  \param user_data An opaque point which must point to a receiver context.
153  \param bit The new bit. Some special values are supported for this field.
154  - SIG_STATUS_CARRIER_UP
155  - SIG_STATUS_CARRIER_DOWN
156  - SIG_STATUS_TRAINING_SUCCEEDED
157  - SIG_STATUS_TRAINING_FAILED
158  - SIG_STATUS_END_OF_DATA */
159 SPAN_DECLARE(void) async_rx_put_bit(void *user_data, int bit);
160 
161 /*! Initialise an asynchronous data receiver context.
162  \brief Initialise an asynchronous data receiver context.
163  \param s The receiver context.
164  \param data_bits The number of data bits.
165  \param parity_bits The type of parity.
166  \param stop_bits The number of stop bits.
167  \param use_v14 True if V.14 rate adaption processing should be used.
168  \param put_byte The callback routine used to put the received data.
169  \param user_data An opaque pointer.
170  \return A pointer to the initialised context, or NULL if there was a problem. */
172  int data_bits,
173  int parity_bits,
174  int stop_bits,
175  bool use_v14,
177  void *user_data);
178 
179 SPAN_DECLARE(int) async_rx_release(async_rx_state_t *s);
180 
181 SPAN_DECLARE(int) async_rx_free(async_rx_state_t *s);
182 
183 /*! Set a minimum number of bit times of stop bit state before character transmission commences.
184  \brief Set a minimum number of bit times of stop bit state before character transmission commences.
185  \param user_data An opaque point which must point to a transmitter context.
186  \param the number of bits. */
187 SPAN_DECLARE(void) async_tx_presend_bits(async_tx_state_t *s, int bits);
188 
189 /*! Get the next bit of a transmitted serial bit stream.
190  \brief Get the next bit of a transmitted serial bit stream.
191  \param user_data An opaque point which must point to a transmitter context.
192  \return the next bit, or PUTBIT_END_OF_DATA to indicate the data stream has ended. */
193 SPAN_DECLARE(int) async_tx_get_bit(void *user_data);
194 
195 /*! Initialise an asynchronous data transmit context.
196  \brief Initialise an asynchronous data transmit context.
197  \param s The transmitter context.
198  \param data_bits The number of data bit.
199  \param parity_bits The type of parity.
200  \param stop_bits The number of stop bits.
201  \param use_v14 True if V.14 rate adaption processing should be used.
202  \param get_byte The callback routine used to get the data to be transmitted.
203  \param user_data An opaque pointer.
204  \return A pointer to the initialised context, or NULL if there was a problem. */
206  int data_bits,
207  int parity_bits,
208  int stop_bits,
209  bool use_v14,
210  get_byte_func_t get_byte,
211  void *user_data);
212 
213 SPAN_DECLARE(int) async_tx_release(async_tx_state_t *s);
214 
215 SPAN_DECLARE(int) async_tx_free(async_tx_state_t *s);
216 
217 #if defined(__cplusplus)
218 }
219 #endif
220 
221 #endif
222 /*- End of file ------------------------------------------------------------*/
int(* get_msg_func_t)(void *user_data, uint8_t *msg, int max_len)
Definition: async.h:98
void(* modem_status_func_t)(void *user_data, int status)
Definition: async.h:113
@ SIG_STATUS_LINK_CONNECTED
The link protocol (e.g. V.42) has connected.
Definition: async.h:85
@ SIG_STATUS_BREAK
A break signal (e.g. an async break) has been received.
Definition: async.h:75
@ SIG_STATUS_TRAINING_FAILED
The modem has failed to train.
Definition: async.h:67
@ SIG_STATUS_LINK_ERROR
An error has occurred in the link protocol (e.g. V.42).
Definition: async.h:89
@ SIG_STATUS_ABORT
An abort signal (e.g. an HDLC abort) has been received.
Definition: async.h:73
@ SIG_STATUS_MODEM_RETRAIN_OCCURRED
Notification that a modem retrain has occurred.
Definition: async.h:83
@ SIG_STATUS_TRAINING_SUCCEEDED
The modem has trained, and is ready for data exchange.
Definition: async.h:65
@ SIG_STATUS_CARRIER_UP
The carrier signal is up. This merely indicates that carrier energy has been seen....
Definition: async.h:58
@ SIG_STATUS_CARRIER_DOWN
The carrier signal has dropped.
Definition: async.h:54
@ SIG_STATUS_END_OF_DATA
The data stream has ended.
Definition: async.h:71
@ SIG_STATUS_FRAMING_OK
Packet framing (e.g. HDLC framing) is OK.
Definition: async.h:69
@ SIG_STATUS_TRAINING_IN_PROGRESS
The modem is training. This is an early indication that the signal seems to be of the right type....
Definition: async.h:63
@ SIG_STATUS_OCTET_REPORT
Regular octet report for things like HDLC to the MTP standards.
Definition: async.h:79
@ SIG_STATUS_SHUTDOWN_COMPLETE
A modem has completed its task, and shut down.
Definition: async.h:77
@ SIG_STATUS_POOR_SIGNAL_QUALITY
Notification that a modem has detected signal quality degradation.
Definition: async.h:81
@ SIG_STATUS_LINK_DISCONNECTED
The link protocol (e.g. V.42) has disconnected.
Definition: async.h:87
@ SIG_STATUS_LINK_IDLE
Keep the link in an idle state, as there is nothing to send.
Definition: async.h:91
@ ASYNC_PARITY_NONE
Definition: async.h:132
@ ASYNC_PARITY_ODD
Definition: async.h:136
@ ASYNC_PARITY_EVEN
Definition: async.h:134
void(* put_bit_func_t)(void *user_data, int bit)
Definition: async.h:107
const char * signal_status_to_str(int status)
Convert a signal status to a short text description.
Definition: async.c:49
void async_tx_presend_bits(async_tx_state_t *s, int bits)
Set a minimum number of bit times of stop bit state before character transmission commences.
Definition: async.c:268
int(* get_byte_func_t)(void *user_data)
Definition: async.h:104
void(* put_byte_func_t)(void *user_data, int byte)
Definition: async.h:101
void(* put_msg_func_t)(void *user_data, const uint8_t *msg, int len)
Definition: async.h:95
void async_rx_put_bit(void *user_data, int bit)
Accept a bit from a received serial bit stream.
Definition: async.c:93
async_tx_state_t * async_tx_init(async_tx_state_t *s, int data_bits, int parity_bits, int stop_bits, bool use_v14, get_byte_func_t get_byte, void *user_data)
Initialise an asynchronous data transmit context.
Definition: async.c:274
int(* get_bit_func_t)(void *user_data)
Definition: async.h:110
int async_tx_get_bit(void *user_data)
Get the next bit of a transmitted serial bit stream.
Definition: async.c:218
async_rx_state_t * async_rx_init(async_rx_state_t *s, int data_bits, int parity_bits, int stop_bits, bool use_v14, put_byte_func_t put_byte, void *user_data)
Initialise an asynchronous data receiver context.
Definition: async.c:174
Definition: private/async.h:65
int data_bits
The number of data bits per character.
Definition: private/async.h:67
bool use_v14
True if V.14 rate adaption processing should be performed.
Definition: private/async.h:73
int stop_bits
The number of stop bits per character.
Definition: private/async.h:71
put_byte_func_t put_byte
A pointer to the callback routine used to handle received characters.
Definition: private/async.h:75
void * user_data
An opaque pointer passed when calling put_byte.
Definition: private/async.h:77
Definition: private/async.h:35