*
* \brief AFSK1200 modem.
*
- * \version $Id$
* \author Francesco Sacchi <asterix@develer.com>
- *
+ *
* $WIZ$ module_name = "afsk"
* $WIZ$ module_configuration = "bertos/cfg/cfg_afsk.h"
* $WIZ$ module_depends = "timer", "kfile"
+ * $WIZ$ module_hw = "bertos/hw/hw_afsk.h"
*/
-#ifndef DRV_AFSK_H
-#define DRV_AFSK_H
+#ifndef NET_AFSK_H
+#define NET_AFSK_H
-#include <kern/kfile.h>
-#include <cfg/compiler.h>
+#include "cfg/cfg_afsk.h"
#include "hw/hw_afsk.h"
+#include <io/kfile.h>
+#include <cfg/compiler.h>
+#include <struct/fifobuf.h>
+
+
+
+/**
+ * ADC sample rate.
+ * The demodulator filters are designed to work at this frequency.
+ * If you need to change this remember to update afsk_adc_isr().
+ */
+#define SAMPLERATE 9600
+
+/**
+ * Bitrate of the received/transmitted data.
+ * The demodulator filters and decoderes are designed to work at this frequency.
+ * If you need to change this remember to update afsk_adc_isr().
+ */
+#define BITRATE 1200
+
+#define SAMPLEPERBIT (SAMPLERATE / BITRATE)
+
+/**
+ * HDLC (High-Level Data Link Control) context.
+ * Maybe to be moved in a separate HDLC module one day.
+ */
+typedef struct Hdlc
+{
+ uint8_t demod_bits; ///< Bitstream from the demodulator.
+ uint8_t bit_idx; ///< Current received bit.
+ uint8_t currchar; ///< Current received character.
+ bool rxstart; ///< True if an HDLC_FLAG char has been found in the bitstream.
+} Hdlc;
+
+/**
+ * RX FIFO buffer full error.
+ */
+#define AFSK_RXFIFO_OVERRUN BV(0)
+
+/**
+ * AFSK1200 modem context.
+ */
typedef struct Afsk
{
- KFile fd;
+ /** Base "class" */
+ KFile fd;
+
+ /** ADC channel to be used by the demodulator */
+ int adc_ch;
+
+ /** DAC channel to be used by the modulator */
+ int dac_ch;
+
+ /** Current sample of bit for output data. */
+ uint8_t sample_count;
+
+ /** Current character to be modulated */
+ uint8_t curr_out;
+
+ /** Mask of current modulated bit */
+ uint8_t tx_bit;
+
+ /** True if bit stuff is allowed, false otherwise */
+ bool bit_stuff;
+
+ /** Counter for bit stuffing */
+ uint8_t stuff_cnt;
+ /**
+ * DDS phase accumulator for generating modulated data.
+ */
+ uint16_t phase_acc;
+
+ /** Current phase increment for current modulated bit */
+ uint16_t phase_inc;
+
+ /** Delay line used to delay samples by (SAMPLEPERBIT / 2) */
+ FIFOBuffer delay_fifo;
+
+ /**
+ * Buffer for delay FIFO.
+ * The 1 is added because the FIFO macros need
+ * 1 byte more to handle a buffer (SAMPLEPERBIT / 2) bytes long.
+ */
+ int8_t delay_buf[SAMPLEPERBIT / 2 + 1];
+
+ /** FIFO for received data */
+ FIFOBuffer rx_fifo;
+
+ /** FIFO rx buffer */
+ uint8_t rx_buf[CONFIG_AFSK_RX_BUFLEN];
+
+ /** FIFO for transmitted data */
+ FIFOBuffer tx_fifo;
+
+ /** FIFO tx buffer */
+ uint8_t tx_buf[CONFIG_AFSK_TX_BUFLEN];
+
+ /** IIR filter X cells, used to filter sampled data by the demodulator */
+ int16_t iir_x[2];
+
+ /** IIR filter Y cells, used to filter sampled data by the demodulator */
+ int16_t iir_y[2];
+
+ /**
+ * Bits sampled by the demodulator are here.
+ * Since ADC samplerate is higher than the bitrate, the bits here are
+ * SAMPLEPERBIT times the bitrate.
+ */
+ uint8_t sampled_bits;
+
+ /**
+ * Current phase, needed to know when the bitstream at ADC speed
+ * should be sampled.
+ */
+ int8_t curr_phase;
+
+ /** Bits found by the demodulator at the correct bitrate speed. */
+ uint8_t found_bits;
+
+ /** True while modem sends data */
+ volatile bool sending;
+
+ /**
+ * AFSK modem status.
+ * If 0 all is ok, otherwise errors are present.
+ */
+ volatile int status;
+
+ /** Hdlc context */
+ Hdlc hdlc;
+
+ /**
+ * Preamble length.
+ * When the AFSK modem wants to send data, before sending the actual data,
+ * shifts out preamble_len HDLC_FLAG characters.
+ * This helps to synchronize the demodulator filters on the receiver side.
+ */
+ uint16_t preamble_len;
+
+ /**
+ * Trailer length.
+ * After sending the actual data, the AFSK shifts out
+ * trailer_len HDLC_FLAG characters.
+ * This helps to synchronize the demodulator filters on the receiver side.
+ */
+ uint16_t trailer_len;
} Afsk;
#define KFT_AFSK MAKE_ID('A', 'F', 'S', 'K')
return (Afsk *)fd;
}
-void afsk_init(Afsk *af);
-#define HDLC_FLAG 0x7E
-#define HDLC_RESET 0x7F
-#define AFSK_ESC 0x1B
+void afsk_adc_isr(Afsk *af, int8_t sample);
+uint8_t afsk_dac_isr(Afsk *af);
+void afsk_init(Afsk *af, int adc_ch, int dac_ch);
+
+
+/**
+ * \name Afsk filter types.
+ * $WIZ$ afsk_filter_list = "AFSK_BUTTERWORTH", "AFSK_CHEBYSHEV"
+ * \{
+ */
+#define AFSK_BUTTERWORTH 0
+#define AFSK_CHEBYSHEV 1
+/* \} */
+
+int afsk_testSetup(void);
+int afsk_testRun(void);
+int afsk_testTearDown(void);
-#endif
+#endif /* NET_AFSK_H */
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