mirror of
https://github.com/markqvist/OpenModem.git
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96 lines
2.6 KiB
C
96 lines
2.6 KiB
C
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#ifndef FSK_MODEM_H
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#define FSK_MODEM_H
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#include "config.h"
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#include "hardware.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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#define SAMPLERATE 9600
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#define BITRATE 1200
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#define SAMPLESPERBIT (SAMPLERATE / BITRATE)
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typedef struct Hdlc
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{
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uint8_t demodulatedBits; // Incoming bitstream from demodulator
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uint8_t bitIndex; // The current received bit in the current received byte
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uint8_t currentByte; // The byte we're currently receiving
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bool receiving; // Whether or not where actually receiving data (or just noise ;P)
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} Hdlc;
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#define RX_OVERRUN BV(0)
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typedef struct Afsk
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{
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KFile fd;
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// I/O hardware pins
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int adcPin; // Pin for incoming signal
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int dacPin; // Pin for outgoing signal
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// General values
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Hdlc hdlc; // We need a link control structure
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uint16_t preambleLength; // Length of sync preamble
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uint16_t tailLength; // Length of transmission tail
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// Modulation values
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uint8_t sampleIndex; // Current sample index for outgoing bit
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uint8_t currentOutputByte; // Current byte to be modulated
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uint8_t txBit; // Mask of current modulated bit
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bool bitStuff; // Whether bitstuffing is allowed
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uint8_t bitstuffCount; // Counter for bit-stuffing
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uint16_t phaseAcc; // Phase accumulator
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uint16_t phaseInc; // Phase increment per sample
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FIFOBuffer txFifo; // FIFO for transmit data
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uint8_t txBuf[CONFIG_AFSK_TX_BUFLEN]; // Actial data storage for said FIFO
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volatile bool sending; // Set when modem is sending
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// Demodulation values
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FIFOBuffer delayFifo; // Delayed FIFO for frequency discrimination
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int8_t delayBuf[SAMPLESPERBIT / 2 + 1];// Actual data storage for said FIFO
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FIFOBuffer rxFifo; // FIFO for received data
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uint8_t rxBuf[CONFIG_AFSK_RX_BUFLEN]; // Actual data storage for said FIFO
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int16_t iirX[2]; // IIR Filter X cells
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int16_t iirY[2]; // IIR Filter Y cells
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uint8_t sampledBits; // Bits sampled by the demodulator (at ADC speed)
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int8_t currentPhase; // Current phase of the demodulator
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uint8_t actualBits; // Actual found bits at correct bitrate
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volatile int status; // Status of the modem, 0 means OK
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} Afsk;
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#define KFT_AFSK MAKE_ID('F', 'S', 'K', 'M')
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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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#define AFSK_BUTTERWORTH 0
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#define AFSK_CHEBYSHEV 1
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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
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