transceiver/Src/oregon.c

#include "app.h"
#include "nexa.h"
#include "oregon.h"

// Constructor must run resetOV3Decoder()

static int decode(int width);
static void done ();
static boolean isDone();


static unsigned char total_bits, bits, flip, state, pos, data[25];

enum { UNKNOWN, T0, T1, T2, T3, OK, DONE };


    boolean nextPulseoregonV3(unsigned int width) {
        if (state != DONE)
        
            switch (decode(width)) {
                case -1: resetOV3Decoder(); break;
                case 1:  done(); break;
            }
        return isDone();
    }
    
    static boolean isDone() {
      return state == DONE;
    }

    const unsigned char* getOV3Data (unsigned char *count) {
        *count = pos;
        return data; 
    }
    
    void resetOV3Decoder () {
        total_bits = bits = pos = flip = 0;
        state = UNKNOWN;
    }
    
   
    // V3-Version of the gitBit-function
    void gotBit (char value) {
        data[pos] = (data[pos] >> 1) | (value ? 0x80 : 00);
        total_bits++;
        pos = total_bits >> 3;
        if (pos >= sizeof data) {
            resetOV3Decoder();
            return;
        }
        state = OK;
    }
    
    // store a bit using Manchester encoding
    void manchester (char value) {
        flip ^= value; // manchester code, long pulse flips the bit
        gotBit(flip);
    }
   
    static void done () {
        while (bits)
            gotBit(0); // padding
        state = DONE;
    }


    

    
    static int decode (int width) {
        if (200 <= width && width < 1200) {
            char w = width >= 700;
            switch (state) {
                case UNKNOWN:
                    if (w == 0)
                        ++flip;
                    else if (32 <= flip) {
                        flip = 1;
                        manchester(1);
                    } else
                        return -1;
                    break;
                case OK:
                    if (w == 0)
                        state = T0;
                    else
                        manchester(1);
                    break;
                case T0:
                    if (w == 0)
                        manchester(0);
                    else
                        return -1;
                    break;
            }
        } else {
            return -1;
        }
        return  total_bits == 80 ? 1: 0;
    }

/*    
    // move bits to the front so that all the bits are aligned to the end
    static void alignTail(char max) {
        // align bits
        if (bits != 0) {
            data[pos] >>= 8 - bits;
            for (char i = 0; i < pos; ++i)
                data[i] = (data[i] >> bits) | (data[i+1] << (8 - bits));
            bits = 0;
        }
        // optionally shift bytes down if there are too many of 'em
        if (max > 0 && pos > max) {
            char n = pos - max;
            pos = max;
            for (char i = 0; i < pos; ++i)
                data[i] = data[i+n];
        }
    }
*/

/*    
    static void reverseBits () {
        for (char i = 0; i < pos; ++i) {
            char b = data[i];
            for (char j = 0; j < 8; ++j) {
                data[i] = (data[i] << 1) | (b & 1);
                b >>= 1;
            }
        }
    }
*/

/*    
    static void reverseNibbles () {
        for (char i = 0; i < pos; ++i)
            data[i] = (data[i] << 4) | (data[i] >> 4);
    }
*/