2 * SpanDSP - a series of DSP components for telephony
4 * async.h - Asynchronous serial bit stream encoding and decoding
6 * Written by Steve Underwood <steveu@coppice.org>
8 * Copyright (C) 2003 Steve Underwood
10 * All rights reserved.
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.
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.
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.
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
34 - Odd, even or no parity.
35 - 5, 6, 7, or 8 bit characters.
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.
40 \section async_page_sec_2 The transmitter
43 \section async_page_sec_3 The receiver
47 #if !defined(_SPANDSP_ASYNC_H_)
48 #define _SPANDSP_ASYNC_H_
50 /*! Special "bit" values for the bitstream put and get functions, and the signal status functions. */
53 /*! \brief The carrier signal has dropped. */
54 SIG_STATUS_CARRIER_DOWN = -1,
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. */
58 SIG_STATUS_CARRIER_UP = -2,
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
63 SIG_STATUS_TRAINING_IN_PROGRESS = -3,
64 /*! \brief The modem has trained, and is ready for data exchange. */
65 SIG_STATUS_TRAINING_SUCCEEDED = -4,
66 /*! \brief The modem has failed to train. */
67 SIG_STATUS_TRAINING_FAILED = -5,
68 /*! \brief Packet framing (e.g. HDLC framing) is OK. */
69 SIG_STATUS_FRAMING_OK = -6,
70 /*! \brief The data stream has ended. */
71 SIG_STATUS_END_OF_DATA = -7,
72 /*! \brief An abort signal (e.g. an HDLC abort) has been received. */
73 SIG_STATUS_ABORT = -8,
74 /*! \brief A break signal (e.g. an async break) has been received. */
75 SIG_STATUS_BREAK = -9,
76 /*! \brief A modem has completed its task, and shut down. */
77 SIG_STATUS_SHUTDOWN_COMPLETE = -10,
78 /*! \brief Regular octet report for things like HDLC to the MTP standards. */
79 SIG_STATUS_OCTET_REPORT = -11,
80 /*! \brief Notification that a modem has detected signal quality degradation. */
81 SIG_STATUS_POOR_SIGNAL_QUALITY = -12,
82 /*! \brief Notification that a modem retrain has occurred. */
83 SIG_STATUS_MODEM_RETRAIN_OCCURRED = -13
86 /*! Message put function for data pumps */
87 typedef void (*put_msg_func_t)(void *user_data, const uint8_t *msg, int len);
89 /*! Message get function for data pumps */
90 typedef int (*get_msg_func_t)(void *user_data, uint8_t *msg, int max_len);
92 /*! Byte put function for data pumps */
93 typedef void (*put_byte_func_t)(void *user_data, int byte);
95 /*! Byte get function for data pumps */
96 typedef int (*get_byte_func_t)(void *user_data);
98 /*! Bit put function for data pumps */
99 typedef void (*put_bit_func_t)(void *user_data, int bit);
101 /*! Bit get function for data pumps */
102 typedef int (*get_bit_func_t)(void *user_data);
104 /*! Completion callback function for tx data pumps */
105 typedef void (*modem_tx_status_func_t)(void *user_data, int status);
107 /*! Completion callback function for rx data pumps */
108 typedef void (*modem_rx_status_func_t)(void *user_data, int status);
112 /*! No parity bit should be used */
113 ASYNC_PARITY_NONE = 0,
114 /*! An even parity bit will exist, after the data bits */
116 /*! An odd parity bit will exist, after the data bits */
121 Asynchronous data transmit descriptor. This defines the state of a single
122 working instance of a byte to asynchronous serial converter, for use
125 typedef struct async_tx_state_s async_tx_state_t;
128 Asynchronous data receive descriptor. This defines the state of a single
129 working instance of an asynchronous serial to byte converter, for use
132 typedef struct async_rx_state_s async_rx_state_t;
134 #if defined(__cplusplus)
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);
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. */
155 SPAN_DECLARE(async_tx_state_t *) async_tx_init(async_tx_state_t *s,
160 get_byte_func_t get_byte,
163 SPAN_DECLARE(int) async_tx_release(async_tx_state_t *s);
165 SPAN_DECLARE(int) async_tx_free(async_tx_state_t *s);
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);
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. */
183 SPAN_DECLARE(async_rx_state_t *) async_rx_init(async_rx_state_t *s,
188 put_byte_func_t put_byte,
191 SPAN_DECLARE(int) async_rx_release(async_rx_state_t *s);
193 SPAN_DECLARE(int) async_rx_free(async_rx_state_t *s);
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);
206 #if defined(__cplusplus)
211 /*- End of file ------------------------------------------------------------*/