227 lines
5.6 KiB
C
227 lines
5.6 KiB
C
/**
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* \file
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* <!--
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* This file is part of BeRTOS.
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*
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* Bertos is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* As a special exception, you may use this file as part of a free software
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* library without restriction. Specifically, if other files instantiate
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* templates or use macros or inline functions from this file, or you compile
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* this file and link it with other files to produce an executable, this
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* file does not by itself cause the resulting executable to be covered by
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* the GNU General Public License. This exception does not however
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* invalidate any other reasons why the executable file might be covered by
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* the GNU General Public License.
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*
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* Copyright 2008 Develer S.r.l. (http://www.develer.com/)
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*
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* -->
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*
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* \brief AFSK1200 modem.
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*
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* \author Francesco Sacchi <batt@develer.com>
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*
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* $WIZ$ module_name = "afsk"
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* $WIZ$ module_configuration = "bertos/cfg/cfg_afsk.h"
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* $WIZ$ module_depends = "timer", "kfile"
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* $WIZ$ module_hw = "bertos/hw/hw_afsk.h"
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*/
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#ifndef NET_AFSK_H
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#define NET_AFSK_H
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#include "cfg/cfg_afsk.h"
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#include "hw/hw_afsk.h"
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#include <cfg/compiler.h>
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#include <io/kfile.h>
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#include <struct/fifobuf.h>
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/**
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* ADC sample rate.
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* The demodulator filters are designed to work at this frequency.
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* If you need to change this remember to update afsk_adc_isr().
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*/
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#define SAMPLERATE 9600
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/**
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* Bitrate of the received/transmitted data.
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* The demodulator filters and decoderes are designed to work at this frequency.
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* If you need to change this remember to update afsk_adc_isr().
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*/
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#define BITRATE 1200
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#define SAMPLEPERBIT (SAMPLERATE / BITRATE)
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/**
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* HDLC (High-Level Data Link Control) context.
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* Maybe to be moved in a separate HDLC module one day.
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*/
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typedef struct Hdlc
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{
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uint8_t demod_bits; ///< Bitstream from the demodulator.
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uint8_t bit_idx; ///< Current received bit.
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uint8_t currchar; ///< Current received character.
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bool rxstart; ///< True if an HDLC_FLAG char has been found in the bitstream.
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} Hdlc;
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/**
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* RX FIFO buffer full error.
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*/
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#define AFSK_RXFIFO_OVERRUN BV(0)
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/**
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* AFSK1200 modem context.
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*/
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typedef struct Afsk
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{
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/** Base "class" */
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KFile fd;
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/** ADC channel to be used by the demodulator */
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int adc_ch;
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/** DAC channel to be used by the modulator */
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int dac_ch;
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/** Current sample of bit for output data. */
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uint8_t sample_count;
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/** Current character to be modulated */
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uint8_t curr_out;
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/** Mask of current modulated bit */
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uint8_t tx_bit;
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/** True if bit stuff is allowed, false otherwise */
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bool bit_stuff;
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/** Counter for bit stuffing */
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uint8_t stuff_cnt;
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/**
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* DDS phase accumulator for generating modulated data.
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*/
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uint16_t phase_acc;
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/** Current phase increment for current modulated bit */
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uint16_t phase_inc;
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/** Delay line used to delay samples by (SAMPLEPERBIT / 2) */
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FIFOBuffer delay_fifo;
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/**
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* Buffer for delay FIFO.
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* The 1 is added because the FIFO macros need
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* 1 byte more to handle a buffer (SAMPLEPERBIT / 2) bytes long.
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*/
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int8_t delay_buf[SAMPLEPERBIT / 2 + 1];
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/** FIFO for received data */
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FIFOBuffer rx_fifo;
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/** FIFO rx buffer */
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uint8_t rx_buf[CONFIG_AFSK_RX_BUFLEN];
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/** FIFO for transmitted data */
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FIFOBuffer tx_fifo;
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/** FIFO tx buffer */
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uint8_t tx_buf[CONFIG_AFSK_TX_BUFLEN];
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/** IIR filter X cells, used to filter sampled data by the demodulator */
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int16_t iir_x[2];
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/** IIR filter Y cells, used to filter sampled data by the demodulator */
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int16_t iir_y[2];
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/**
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* Bits sampled by the demodulator are here.
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* Since ADC samplerate is higher than the bitrate, the bits here are
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* SAMPLEPERBIT times the bitrate.
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*/
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uint8_t sampled_bits;
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/**
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* Current phase, needed to know when the bitstream at ADC speed
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* should be sampled.
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*/
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int8_t curr_phase;
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/** Bits found by the demodulator at the correct bitrate speed. */
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uint8_t found_bits;
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/** True while modem sends data */
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volatile bool sending;
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/**
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* AFSK modem status.
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* If 0 all is ok, otherwise errors are present.
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*/
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volatile int status;
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/** Hdlc context */
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Hdlc hdlc;
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/**
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* Preamble length.
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* When the AFSK modem wants to send data, before sending the actual data,
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* shifts out preamble_len HDLC_FLAG characters.
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* This helps to synchronize the demodulator filters on the receiver side.
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*/
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uint16_t preamble_len;
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/**
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* Trailer length.
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* After sending the actual data, the AFSK shifts out
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* trailer_len HDLC_FLAG characters.
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* This helps to synchronize the demodulator filters on the receiver side.
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*/
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uint16_t trailer_len;
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} Afsk;
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#define KFT_AFSK MAKE_ID('A', 'F', 'S', 'K')
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INLINE Afsk *AFSK_CAST(KFile *fd)
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{
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ASSERT(fd->_type == KFT_AFSK);
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return (Afsk *)fd;
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}
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void afsk_adc_isr(Afsk *af, int8_t sample);
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uint8_t afsk_dac_isr(Afsk *af);
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void afsk_init(Afsk *af, int adc_ch, int dac_ch);
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/**
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* \name Afsk filter types.
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* $WIZ$ afsk_filter_list = "AFSK_BUTTERWORTH", "AFSK_CHEBYSHEV"
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* \{
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*/
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#define AFSK_BUTTERWORTH 0
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#define AFSK_CHEBYSHEV 1
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/* \} */
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int afsk_testSetup(void);
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int afsk_testRun(void);
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int afsk_testTearDown(void);
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#endif /* NET_AFSK_H */
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