Fix doc.

[bertos.git] / bertos / net / afsk.h

diff --git a/bertos/net/afsk.h b/bertos/net/afsk.h
index 4ab20c5053391c2777c967316e7782033fb14618..d9ce6ff0ca0d59c225a899d0ce31a2d2e9f33383 100644 (file)
--- a/bertos/net/afsk.h
+++ b/bertos/net/afsk.h
@@ -52,18 +52,52 @@
 #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. */
@@ -98,29 +132,66 @@ typedef struct Afsk
         */
        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;
 
@@ -132,13 +203,14 @@ INLINE Afsk *AFSK_CAST(KFile *fd)
   return (Afsk *)fd;
 }
 
-void afsk_adc_isr(Afsk *af, int8_t curr_sample);
-void afsk_dac_isr(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"
  * \{
  */