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comparison spandsp-0.0.3/spandsp-0.0.3/src/spandsp/async.h @ 5:f762bf195c4b

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import spandsp-0.0.3
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Fri, 25 Jun 2010 16:00:21 +0200
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4:26cd8f1ef0b1 5:f762bf195c4b
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 General Public License version 2, as
14 * 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 General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 *
25 * $Id: async.h,v 1.6 2006/10/24 13:22:01 steveu Exp $
26 */
27
28 /*! \file */
29
30 /*! \page async_page Asynchronous bit stream processing
31 \section async_page_sec_1 What does it do?
32 The asynchronous serial bit stream processing module provides
33 generation and decoding facilities for most asynchronous data
34 formats. It supports:
35 - 1 or 2 stop bits.
36 - Odd, even or no parity.
37 - 5, 6, 7, or 8 bit characters.
38 - V.14 rate adaption.
39 The input to this module is a bit stream. This means any symbol synchronisation
40 and decoding must occur before data is fed to this module.
41
42 \section async_page_sec_2 The transmitter
43 ???.
44
45 \section async_page_sec_3 The receiver
46 ???.
47 */
48
49 #if !defined(_ASYNC_H_)
50 #define _ASYNC_H_
51
52 /* Special "bit" values for the put and get bit functions */
53 enum
54 {
55 /*! \brief The carrier signal has dropped. */
56 PUTBIT_CARRIER_DOWN = -1,
57 /*! \brief The carrier signal is up. This merely indicates that carrier
58 energy has been seen. It is not an indication that the carrier is either
59 valid, or of the expected type. */
60 PUTBIT_CARRIER_UP = -2,
61 /*! \brief The modem is training. This is an early indication that the
62 signal seems to be of the right type. This may be needed in time critical
63 applications, like T.38, to forward an early indication of what is happening
64 on the wire. */
65 PUTBIT_TRAINING_IN_PROGRESS = -3,
66 /*! \brief The modem has trained, and is ready for data exchange. */
67 PUTBIT_TRAINING_SUCCEEDED = -4,
68 /*! \brief The modem has failed to train. */
69 PUTBIT_TRAINING_FAILED = -5,
70 /*! \brief Packet framing (e.g. HDLC framing) is OK. */
71 PUTBIT_FRAMING_OK = -6,
72 /*! \brief The data stream has ended. */
73 PUTBIT_END_OF_DATA = -7,
74 /*! \brief An abort signal (e.g. an HDLC abort) has been received. */
75 PUTBIT_ABORT = -8,
76 /*! \brief A break signal (e.g. an async break) has been received. */
77 PUTBIT_BREAK = -9
78 };
79
80 /*! Message put function for data pumps */
81 typedef void (*put_msg_func_t)(void *user_data, const uint8_t *msg, int len);
82
83 /*! Message get function for data pumps */
84 typedef int (*get_msg_func_t)(void *user_data, uint8_t *msg, int max_len);
85
86 /*! Byte put function for data pumps */
87 typedef void (*put_byte_func_t)(void *user_data, int byte);
88
89 /*! Byte get function for data pumps */
90 typedef int (*get_byte_func_t)(void *user_data);
91
92 /*! Bit put function for data pumps */
93 typedef void (*put_bit_func_t)(void *user_data, int bit);
94
95 /*! Bit get function for data pumps */
96 typedef int (*get_bit_func_t)(void *user_data);
97
98 /*! No parity bit should be used */
99 #define ASYNC_PARITY_NONE 0
100 /*! An even parity bit will exist, after the data bits */
101 #define ASYNC_PARITY_EVEN 1
102 /*! An odd parity bit will exist, after the data bits */
103 #define ASYNC_PARITY_ODD 2
104
105 /*!
106 Asynchronous data transmit descriptor. This defines the state of a single
107 working instance of a byte to asynchronous serial converter, for use
108 in FSK modems.
109 */
110 typedef struct
111 {
112 /*! \brief The number of data bits per character. */
113 int data_bits;
114 /*! \brief The type of parity. */
115 int parity;
116 /*! \brief The number of stop bits per character. */
117 int stop_bits;
118 /*! \brief A pointer to the callback routine used to get characters to be transmitted. */
119 get_byte_func_t get_byte;
120 /*! \brief An opaque pointer passed when calling get_byte. */
121 void *user_data;
122
123 /*! \brief A current, partially transmitted, character. */
124 int byte_in_progress;
125 /*! \brief The current bit position within a partially transmitted character. */
126 int bitpos;
127 int parity_bit;
128 } async_tx_state_t;
129
130 /*!
131 Asynchronous data receive descriptor. This defines the state of a single
132 working instance of an asynchronous serial to byte converter, for use
133 in FSK modems.
134 */
135 typedef struct
136 {
137 /*! \brief The number of data bits per character. */
138 int data_bits;
139 /*! \brief The type of parity. */
140 int parity;
141 /*! \brief The number of stop bits per character. */
142 int stop_bits;
143 /*! \brief TRUE if V.14 rate adaption processing should be performed. */
144 int use_v14;
145 /*! \brief A pointer to the callback routine used to handle received characters. */
146 put_byte_func_t put_byte;
147 /*! \brief An opaque pointer passed when calling put_byte. */
148 void *user_data;
149
150 /*! \brief A current, partially complete, character. */
151 int byte_in_progress;
152 /*! \brief The current bit position within a partially complete character. */
153 int bitpos;
154 int parity_bit;
155
156 int parity_errors;
157 int framing_errors;
158 } async_rx_state_t;
159
160 #ifdef __cplusplus
161 extern "C" {
162 #endif
163
164 /*! Initialise an asynchronous data transmit context.
165 \brief Initialise an asynchronous data transmit context.
166 \param s The transmitter context.
167 \param data_bits The number of data bit.
168 \param parity_bits The type of parity.
169 \param stop_bits The number of stop bits.
170 \param use_v14 TRUE if V.14 rate adaption processing should be used.
171 \param get_byte The callback routine used to get the data to be transmitted.
172 \param user_data An opaque pointer. */
173 void async_tx_init(async_tx_state_t *s,
174 int data_bits,
175 int parity_bits,
176 int stop_bits,
177 int use_v14,
178 get_byte_func_t get_byte,
179 void *user_data);
180
181 /*! Get the next bit of a transmitted serial bit stream.
182 \brief Get the next bit of a transmitted serial bit stream.
183 \param user_data An opaque point which must point to a transmitter context.
184 \return the next bit, or PUTBIT_END_OF_DATA to indicate the data stream has ended. */
185 int async_tx_get_bit(void *user_data);
186
187 /*! Initialise an asynchronous data receiver context.
188 \brief Initialise an asynchronous data receiver context.
189 \param s The receiver context.
190 \param data_bits The number of data bits.
191 \param parity_bits The type of parity.
192 \param stop_bits The number of stop bits.
193 \param use_v14 TRUE if V.14 rate adaption processing should be used.
194 \param put_byte The callback routine used to put the received data.
195 \param user_data An opaque pointer. */
196 void async_rx_init(async_rx_state_t *s,
197 int data_bits,
198 int parity_bits,
199 int stop_bits,
200 int use_v14,
201 put_byte_func_t put_byte,
202 void *user_data);
203
204 /*! Accept a bit from a received serial bit stream
205 \brief Accept a bit from a received serial bit stream
206 \param user_data An opaque point which must point to a receiver context.
207 \param bit The new bit. Some special values are supported for this field.
208 - PUTBIT_CARRIER_UP
209 - PUTBIT_CARRIER_DOWN
210 - PUTBIT_TRAINING_SUCCEEDED
211 - PUTBIT_TRAINING_FAILED
212 - PUTBIT_END_OF_DATA */
213 void async_rx_put_bit(void *user_data, int bit);
214
215 #ifdef __cplusplus
216 }
217 #endif
218
219 #endif
220 /*- End of file ------------------------------------------------------------*/

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