*
* \brief AFSK1200 modem.
*
- * \version $Id$
* \author Francesco Sacchi <asterix@develer.com>
*
* $WIZ$ module_name = "afsk"
* $WIZ$ module_hw = "bertos/hw/hw_afsk.h"
*/
-#ifndef DRV_AFSK_H
-#define DRV_AFSK_H
+#ifndef NET_AFSK_H
+#define NET_AFSK_H
#include "cfg/cfg_afsk.h"
#include "hw/hw_afsk.h"
#include <struct/fifobuf.h>
-// Demodulator constants
+
+/**
+ * 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
{
+ /** 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;
*/
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;
- uint8_t found_bits;
+
+ /**
+ * Current phase, needed to know when the bitstream at ADC speed
+ * should be sampled.
+ */
int8_t curr_phase;
- /* True while modem sends data */
+ /** 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;
- bool hdlc_rxstart;
- uint8_t hdlc_currchar;
- uint8_t hdlc_bit_idx;
- uint8_t hdlc_demod_bits;
+ /** 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;
return (Afsk *)fd;
}
-void afsk_adc_isr(Afsk *af, int8_t curr_sample);
-void afsk_dac_isr(Afsk *af);
-void afsk_init(Afsk *af);
+
+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 type
+ * \name Afsk filter types.
* $WIZ$ afsk_filter_list = "AFSK_BUTTERWORTH", "AFSK_CHEBYSHEV"
* \{
*/
int afsk_testRun(void);
int afsk_testTearDown(void);
-#endif
+#endif /* NET_AFSK_H */