From c99ac62ee5cd652933bf3c89bb9b443bc5514613 Mon Sep 17 00:00:00 2001
From: Richard Meadows <richardeoin@gmail.com>
Date: Sun, 13 Dec 2015 12:23:51 +0000
Subject: [PATCH] Add support for faster contestia modes

---
 firmware/inc/contestia.h | 15 +++++++++++++++
 firmware/src/contestia.c |  6 +++---
 firmware/src/mfsk.c      | 12 ++++++++----
 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/firmware/inc/contestia.h b/firmware/inc/contestia.h
index bfb3ec8..b48ede9 100644
--- a/firmware/inc/contestia.h
+++ b/firmware/inc/contestia.h
@@ -25,6 +25,21 @@
 #ifndef CONTESTIA_H
 #define CONTESTIA_H
 
+
+/* /\** */
+/*  * Contestia 8/1000 */
+/*  *\/ */
+/* #define CONTESTIA_NUMBER_OF_TONES 8 */
+/* #define CONTESTIA_CHARACTERS_PER_BLOCK 3 */
+/* #define CONTESTIA_CHANNEL_SPACING 16 // Corresponds to 124.88 Hz */
+/* #define CONTESTIA_SYMBOL_RATE 125 */
+/* /\** */
+/*  * Contestia 16/1000 */
+/*  *\/ */
+/* #define CONTESTIA_NUMBER_OF_TONES 16 */
+/* #define CONTESTIA_CHARACTERS_PER_BLOCK 4 */
+/* #define CONTESTIA_CHANNEL_SPACING 8 // Corresponds to 62.44 Hz */
+/* #define CONTESTIA_SYMBOL_RATE 62.5 */
 /**
  * Contestia 32/1000
  */
diff --git a/firmware/src/contestia.c b/firmware/src/contestia.c
index 388749f..882926d 100644
--- a/firmware/src/contestia.c
+++ b/firmware/src/contestia.c
@@ -35,7 +35,7 @@
 /**
  * Current output tones
  */
-int8_t contestia_tones[CONTESTIA_NUMBER_OF_TONES];
+int8_t contestia_tones[32];
 /**
  * Where we are in the current output tones
  */
@@ -80,7 +80,7 @@ uint8_t contestia_tick(void) {
     return 1;
   }
 
-  if (contestia_tone_index < CONTESTIA_NUMBER_OF_TONES) {
+  if (contestia_tone_index < 32) {
     uint8_t binary_code;
     uint8_t grey_code;
 
@@ -97,7 +97,7 @@ uint8_t contestia_tick(void) {
 
   contestia_tone_index++;
 
-  if (contestia_tone_index < CONTESTIA_NUMBER_OF_TONES) {
+  if (contestia_tone_index < 32) {
     return 1;
   }
 
diff --git a/firmware/src/mfsk.c b/firmware/src/mfsk.c
index e63e25e..c4985c0 100644
--- a/firmware/src/mfsk.c
+++ b/firmware/src/mfsk.c
@@ -27,10 +27,12 @@
 #include "samd20.h"
 #include "mfsk.h"
 #include "math/fwht.h"
+#include "contestia.h"
 
 static const uint64_t scrambler_olivia		= 0xE257E6D0291574ECLL;
 static const uint64_t scrambler_contestia	= 0xEDB88320LL;
-
+static const uint16_t shift_olivia		= 13;
+static const uint16_t shift_contestia		= 5;
 /**
  * USEFUL RESOURES =============================================================
  *
@@ -110,7 +112,8 @@ void olivia_mfsk_encode_block(char* block, int8_t* tones)
 {
   size_t bits_per_symbol = 5; /* That is, there are 2^5=32 tones */
 
-  mfsk_encode_block(block, tones, 64, bits_per_symbol, scrambler_olivia, 13);
+  mfsk_encode_block(block, tones, 64, bits_per_symbol,
+                    scrambler_olivia, shift_olivia);
 }
 /**
  * This function encodes a single block of Contestia MFSK
@@ -120,7 +123,7 @@ void olivia_mfsk_encode_block(char* block, int8_t* tones)
  */
 void contestia_mfsk_encode_block(char* block, int8_t* tones)
 {
-  size_t bits_per_symbol = 5; /* That is, there are 2^5=32 tones */
+  size_t bits_per_symbol = CONTESTIA_CHARACTERS_PER_BLOCK; /* That is, there are 2^x tones */
 
   for (uint8_t c_index = 0; c_index < bits_per_symbol; c_index++) {
     char character = block[c_index];
@@ -151,5 +154,6 @@ void contestia_mfsk_encode_block(char* block, int8_t* tones)
   }
 
 
-  mfsk_encode_block(block, tones, 32, bits_per_symbol, scrambler_contestia, 5);
+  mfsk_encode_block(block, tones, 32, bits_per_symbol,
+                    scrambler_contestia, shift_contestia);
 }