Extract some bits.

plugins/channel/lora/lorabits.h

@@ -4,16 +4,25 @@
 */
 
 // Needs adjusting for different sizes
-void LoRaDemod::interleave(char* inout)
+void LoRaDemod::interleave(char* inout, int size)
 {
-	int i, index = 6;
-	char in[index * 2];
-	for (i = 0; i < index; i++)
-		in[i] = in[i + index] = inout[i];
-	// top bits are swapped ?
-	for (i = 0; i < index; i++) {
-		inout[i] = (32 & in[2 + i]) | (16 & in[1 + i]) | (8 & in[3 + i])
+	int i, j;
+	char in[6 * 2];
+	short s;
+
+	for (j = 0; j < size; j+=6) {
+		for (i = 0; i < 6; i++)
+			in[i] = in[i + 6] = inout[i + j];
+		// top bits are swapped
+		for (i = 0; i < 6; i++) {
+			s = (32 & in[2 + i]) | (16 & in[1 + i]) | (8 & in[3 + i])
 				| (4 & in[4 + i]) | (2 & in[5 + i]) | (1 & in[6 + i]);
+			// bits are also  rotated
+			s = (s << 3) | (s >> 3);
+			s &= 63;
+			s = (s >> i) | (s << (6 - i));
+			inout[i + j] = s & 63;
+		}
 	}
 }
 
@@ -22,24 +31,32 @@ short LoRaDemod::toGray(short num)
         return (num >> 1) ^ num;
 }
 
-// ignore FEC, try data in lsb, bigendian
-void LoRaDemod::hamming(char* inout, int size)
+// ignore FEC, try to extract raw bits
+void LoRaDemod::hamming(char* c, int size)
 {
 	int i;
-	char c;
+
 	for (i = 0; i < size; i++) {
-		c = inout[i];
-		c = ((c&1)<<3) | ((c&2)<<1) | ((c&4)>>1) | ((c&8)>>3);
-		inout[i] = c;
+		c[i] = ((c[i] & 1)<<3) | ((c[i] & 2)<<0) | ((c[i] & 4)>>0) | ((c[i] & 8)>>3);
+		i++;
+		c[i] = ((c[i] & 1)<<2) | ((c[i] & 2)<<2) | ((c[i] & 4)>>1) | ((c[i] & 8)>>3);
+		i++;
+		c[i] = ((c[i] & 1)<<3) | ((c[i] & 2)<<1) | ((c[i] & 4)>>1) | ((c[i] & 8)>>3);
+		i++;
+		c[i] = ((c[i] & 1)<<3) | ((c[i] & 2)<<1) | ((c[i] & 4)>>1) | ((c[i] & 8)>>3);
+		i++;
+		c[i] = ((c[i] & 1)<<3) | ((c[i] & 2)<<1) | ((c[i] & 4)>>1) | ((c[i] & 8)>>3);
+		i++;
+		c[i] = ((c[i] & 1)<<3) | ((c[i] & 2)<<1) | ((c[i] & 4)>>2) | ((c[i] & 8)>>2);
 	}
-	inout[i] = 0;
+	c[i] = 0;
 }
 
 // example data whitening (4 bit only - needs 6 bit for FEC)
 void LoRaDemod::prng(char* inout, int size)
 {
 	const char otp[] = {
-	"EHFGKHGMGKGMGHG@FKDN@EHBMGBOLFALO@GIBIICJNMDFIDHAHJHMHBBHLHCHLH@IINCAOJFMLF@EKBDIAJKMNBEMBGMBKLMAHOHFHDB@DH@H@HAIKKDKAOKGDBAMIGIBCMLGCFODFAFNLECBLIHKHNBALJA"
+	"LBMGEJJENKKKJBN@KB@KAEDDMMDONIN@N@KFBGBCMCMCMIBJHBDHNJDJALDHE@A@DFGOBOMIM@M@BBBCBAMBMKDENDLEDKNKNBNHKJ@JADD@EAAADBOCGAGBLCDANFLGDCNGLOMOBIHHMLBHB@BHMJGJBLMLED@B"
 	};
 	int i, maxchars;
 
@@ -47,6 +64,6 @@ void LoRaDemod::prng(char* inout, int size)
 	if (size < maxchars)
 		maxchars = size;
 	for (i = 0; i < maxchars; i++)
-		inout[i] ^= otp[i];
+		inout[i] ^= 0xf & otp[i];
 }
 

plugins/channel/lora/lorademod.cpp

@@ -73,27 +73,27 @@ void LoRaDemod::configure(MessageQueue* messageQueue, Real Bandwidth)
 
 void LoRaDemod::dumpRaw()
 {
-	char hex[] = {"0123456789ABCDEFXXXX"};
 	short bin, j, max;
-	max = m_time / 4 - 3;
-	if (max > 80)
-		max = 80; // 80 symbols is  about 40 chars
 	char text[256];
+
+	max = m_time / 4 - 3;
+	if (max > 100)
+		max = 100; // about 2 symbols to each char
+
 	for ( j=0; j < max; j++) {
 		bin = (history[j * 4 + 12] + m_tune ) & (LORA_SFFT_LEN - 1);
 		text[j] = toGray(bin >> 1);
 	}
-	for ( j=0; j < max; j+=6)
-		interleave(&text[j]);
+	interleave(text, max);
 	prng(text, max);
 	hamming(text, max);
-	for ( j=0; j < max; j++) {
-		text[j] = hex[ (0xf & text[j]) ];
+
+	for ( j=0; j < max / 2; j++) {
+		text[j] = (text[j * 2 + 2] << 4) | (0xf & text[j * 2 + 1]);
+		if ((text[j] < 32 )||( text[j] > 126))
+			text[j] = 0x5f;
 	}
-//	for ( j=0; j < max / 2; j++) {
-//		if ((text[j] < 32 )||( text[j] > 126))
-//			text[j] = 0x5f;
-//	}
+
 	text[j] = 0;
 	printf("%s\n", text);
 }

plugins/channel/lora/lorademod.h

@@ -44,7 +44,7 @@ public:
 
 private:
 	int  detect(Complex sample, Complex angle);
-	void interleave(char* inout);
+	void interleave(char* inout, int size);
 	void dumpRaw(void);
 	short synch (short bin);
 	short toGray(short bin);