diff --git a/cubesatsim/cubesatsim.ino b/cubesatsim/cubesatsim.ino index 3a56ee35..745c6f8c 100644 --- a/cubesatsim/cubesatsim.ino +++ b/cubesatsim/cubesatsim.ino @@ -654,3 +654,677 @@ void sleep(int time) { while ((millis() - startSleep) < time) delay(100); } + +/* + * TelemEncoding.c + * + Fox-1 telemetry encoder + January 2014 Phil Karn KA9Q + This file has two external functions: + void update_rs(unsigned char parity[32],unsigned char data); + int encode_8b10b(int *state,int data). + update_rs() is the Reed-Solomon encoder. Its first argument is the 32-byte + encoder shift register, the second is the 8-bit data byte being encoded. It updates + the shift register in place and returns void. At the end of each frame, it contains + the parities ready for transmission, starting with parity[0]. + Be sure to zero this array before each new frame! + encode_8b10b() is the 8b10b encoder. Its first argument is a pointer to a single integer + with the 1-bit encoder state (the current run disparity, or RD). Initialize it to 0 + JUST ONCE at startup (not between frames). + The second argument is the data byte being encoded. It updates the state and returns + an integer containing the 10-bit encoded word, right justified. + Transmit this word from left to right. + The data argument is an int so it can hold the special value -1 to indicate end of frame; + it generates the 8b10b control word K.28.5, which is used as an inter-frame flag. + Some assert() calls are made to verify legality of arguments. These can be turned off in + production code. + sample frame transmission code: + unsigned char data[64]; // Data block to be sent + unsigned char parity[32]; // RS parities + void transmit_word(int); // User provided transmit function: 10 bits of data in bits 9....0 + int state,i; + state = 0; // Only once at startup, not between frames + memset(parity,0,sizeof(parity); // Do this before every frame + // Transmit the data, updating the RS encoder + for(i=0;i<64;i++){ + update_rs(parity,data[i]); + transmit_word(encode_8b10b(&state,data[i]); + } + // get the RS parities + for(i=0;i<32;i++) + transmit_word(encode_8b10b(&state,parity[i]); + transmit_word(encode_8b10b(&state,-1); // Transmit end-of-frame flag +*/ + + +#include +//#include "Fox.h" +#include "TelemEncoding.h" +#include +#include + +#ifndef NULL +#define NULL ((void *)0) +#endif + +#define NN (0xff) // Frame size in symbols +#define A0 (NN) // special value for log(0) + +int Encode_8b10b[][256] = { + // RD = -1 cases + { + /* 00 */ 0x274, + /* 01 */ 0x1d4, + /* 02 */ 0x2d4, + /* 03 */ 0x71b, + /* 04 */ 0x354, + /* 05 */ 0x69b, + /* 06 */ 0x59b, + /* 07 */ 0x78b, + /* 08 */ 0x394, + /* 09 */ 0x65b, + /* 0a */ 0x55b, + /* 0b */ 0x74b, + /* 0c */ 0x4db, + /* 0d */ 0x6cb, + /* 0e */ 0x5cb, + /* 0f */ 0x174, + /* 10 */ 0x1b4, + /* 11 */ 0x63b, + /* 12 */ 0x53b, + /* 13 */ 0x72b, + /* 14 */ 0x4bb, + /* 15 */ 0x6ab, + /* 16 */ 0x5ab, + /* 17 */ 0x3a4, + /* 18 */ 0x334, + /* 19 */ 0x66b, + /* 1a */ 0x56b, + /* 1b */ 0x364, + /* 1c */ 0x4eb, + /* 1d */ 0x2e4, + /* 1e */ 0x1e4, + /* 1f */ 0x2b4, + /* 20 */ 0x679, + /* 21 */ 0x5d9, + /* 22 */ 0x6d9, + /* 23 */ 0x319, + /* 24 */ 0x759, + /* 25 */ 0x299, + /* 26 */ 0x199, + /* 27 */ 0x389, + /* 28 */ 0x799, + /* 29 */ 0x259, + /* 2a */ 0x159, + /* 2b */ 0x349, + /* 2c */ 0x0d9, + /* 2d */ 0x2c9, + /* 2e */ 0x1c9, + /* 2f */ 0x579, + /* 30 */ 0x5b9, + /* 31 */ 0x239, + /* 32 */ 0x139, + /* 33 */ 0x329, + /* 34 */ 0x0b9, + /* 35 */ 0x2a9, + /* 36 */ 0x1a9, + /* 37 */ 0x7a9, + /* 38 */ 0x739, + /* 39 */ 0x269, + /* 3a */ 0x169, + /* 3b */ 0x769, + /* 3c */ 0x0e9, + /* 3d */ 0x6e9, + /* 3e */ 0x5e9, + /* 3f */ 0x6b9, + /* 40 */ 0x675, + /* 41 */ 0x5d5, + /* 42 */ 0x6d5, + /* 43 */ 0x315, + /* 44 */ 0x755, + /* 45 */ 0x295, + /* 46 */ 0x195, + /* 47 */ 0x385, + /* 48 */ 0x795, + /* 49 */ 0x255, + /* 4a */ 0x155, + /* 4b */ 0x345, + /* 4c */ 0x0d5, + /* 4d */ 0x2c5, + /* 4e */ 0x1c5, + /* 4f */ 0x575, + /* 50 */ 0x5b5, + /* 51 */ 0x235, + /* 52 */ 0x135, + /* 53 */ 0x325, + /* 54 */ 0x0b5, + /* 55 */ 0x2a5, + /* 56 */ 0x1a5, + /* 57 */ 0x7a5, + /* 58 */ 0x735, + /* 59 */ 0x265, + /* 5a */ 0x165, + /* 5b */ 0x765, + /* 5c */ 0x0e5, + /* 5d */ 0x6e5, + /* 5e */ 0x5e5, + /* 5f */ 0x6b5, + /* 60 */ 0x673, + /* 61 */ 0x5d3, + /* 62 */ 0x6d3, + /* 63 */ 0x31c, + /* 64 */ 0x753, + /* 65 */ 0x29c, + /* 66 */ 0x19c, + /* 67 */ 0x38c, + /* 68 */ 0x793, + /* 69 */ 0x25c, + /* 6a */ 0x15c, + /* 6b */ 0x34c, + /* 6c */ 0x0dc, + /* 6d */ 0x2cc, + /* 6e */ 0x1cc, + /* 6f */ 0x573, + /* 70 */ 0x5b3, + /* 71 */ 0x23c, + /* 72 */ 0x13c, + /* 73 */ 0x32c, + /* 74 */ 0x0bc, + /* 75 */ 0x2ac, + /* 76 */ 0x1ac, + /* 77 */ 0x7a3, + /* 78 */ 0x733, + /* 79 */ 0x26c, + /* 7a */ 0x16c, + /* 7b */ 0x763, + /* 7c */ 0x0ec, + /* 7d */ 0x6e3, + /* 7e */ 0x5e3, + /* 7f */ 0x6b3, + /* 80 */ 0x272, + /* 81 */ 0x1d2, + /* 82 */ 0x2d2, + /* 83 */ 0x71d, + /* 84 */ 0x352, + /* 85 */ 0x69d, + /* 86 */ 0x59d, + /* 87 */ 0x78d, + /* 88 */ 0x392, + /* 89 */ 0x65d, + /* 8a */ 0x55d, + /* 8b */ 0x74d, + /* 8c */ 0x4dd, + /* 8d */ 0x6cd, + /* 8e */ 0x5cd, + /* 8f */ 0x172, + /* 90 */ 0x1b2, + /* 91 */ 0x63d, + /* 92 */ 0x53d, + /* 93 */ 0x72d, + /* 94 */ 0x4bd, + /* 95 */ 0x6ad, + /* 96 */ 0x5ad, + /* 97 */ 0x3a2, + /* 98 */ 0x332, + /* 99 */ 0x66d, + /* 9a */ 0x56d, + /* 9b */ 0x362, + /* 9c */ 0x4ed, + /* 9d */ 0x2e2, + /* 9e */ 0x1e2, + /* 9f */ 0x2b2, + /* a0 */ 0x67a, + /* a1 */ 0x5da, + /* a2 */ 0x6da, + /* a3 */ 0x31a, + /* a4 */ 0x75a, + /* a5 */ 0x29a, + /* a6 */ 0x19a, + /* a7 */ 0x38a, + /* a8 */ 0x79a, + /* a9 */ 0x25a, + /* aa */ 0x15a, + /* ab */ 0x34a, + /* ac */ 0x0da, + /* ad */ 0x2ca, + /* ae */ 0x1ca, + /* af */ 0x57a, + /* b0 */ 0x5ba, + /* b1 */ 0x23a, + /* b2 */ 0x13a, + /* b3 */ 0x32a, + /* b4 */ 0x0ba, + /* b5 */ 0x2aa, + /* b6 */ 0x1aa, + /* b7 */ 0x7aa, + /* b8 */ 0x73a, + /* b9 */ 0x26a, + /* ba */ 0x16a, + /* bb */ 0x76a, + /* bc */ 0x0ea, + /* bd */ 0x6ea, + /* be */ 0x5ea, + /* bf */ 0x6ba, + /* c0 */ 0x676, + /* c1 */ 0x5d6, + /* c2 */ 0x6d6, + /* c3 */ 0x316, + /* c4 */ 0x756, + /* c5 */ 0x296, + /* c6 */ 0x196, + /* c7 */ 0x386, + /* c8 */ 0x796, + /* c9 */ 0x256, + /* ca */ 0x156, + /* cb */ 0x346, + /* cc */ 0x0d6, + /* cd */ 0x2c6, + /* ce */ 0x1c6, + /* cf */ 0x576, + /* d0 */ 0x5b6, + /* d1 */ 0x236, + /* d2 */ 0x136, + /* d3 */ 0x326, + /* d4 */ 0x0b6, + /* d5 */ 0x2a6, + /* d6 */ 0x1a6, + /* d7 */ 0x7a6, + /* d8 */ 0x736, + /* d9 */ 0x266, + /* da */ 0x166, + /* db */ 0x766, + /* dc */ 0x0e6, + /* dd */ 0x6e6, + /* de */ 0x5e6, + /* df */ 0x6b6, + /* e0 */ 0x271, + /* e1 */ 0x1d1, + /* e2 */ 0x2d1, + /* e3 */ 0x71e, + /* e4 */ 0x351, + /* e5 */ 0x69e, + /* e6 */ 0x59e, + /* e7 */ 0x78e, + /* e8 */ 0x391, + /* e9 */ 0x65e, + /* ea */ 0x55e, + /* eb */ 0x74e, + /* ec */ 0x4de, + /* ed */ 0x6ce, + /* ee */ 0x5ce, + /* ef */ 0x171, + /* f0 */ 0x1b1, + /* f1 */ 0x637, + /* f2 */ 0x537, + /* f3 */ 0x72e, + /* f4 */ 0x4b7, + /* f5 */ 0x6ae, + /* f6 */ 0x5ae, + /* f7 */ 0x3a1, + /* f8 */ 0x331, + /* f9 */ 0x66e, + /* fa */ 0x56e, + /* fb */ 0x361, + /* fc */ 0x4ee, + /* fd */ 0x2e1, + /* fe */ 0x1e1, + /* ff */ 0x2b1, + }, // RD = +1 cases + { + /* 00 */ 0x58b, + /* 01 */ 0x62b, + /* 02 */ 0x52b, + /* 03 */ 0x314, + /* 04 */ 0x4ab, + /* 05 */ 0x294, + /* 06 */ 0x194, + /* 07 */ 0x074, + /* 08 */ 0x46b, + /* 09 */ 0x254, + /* 0a */ 0x154, + /* 0b */ 0x344, + /* 0c */ 0x0d4, + /* 0d */ 0x2c4, + /* 0e */ 0x1c4, + /* 0f */ 0x68b, + /* 10 */ 0x64b, + /* 11 */ 0x234, + /* 12 */ 0x134, + /* 13 */ 0x324, + /* 14 */ 0x0b4, + /* 15 */ 0x2a4, + /* 16 */ 0x1a4, + /* 17 */ 0x45b, + /* 18 */ 0x4cb, + /* 19 */ 0x264, + /* 1a */ 0x164, + /* 1b */ 0x49b, + /* 1c */ 0x0e4, + /* 1d */ 0x51b, + /* 1e */ 0x61b, + /* 1f */ 0x54b, + /* 20 */ 0x189, + /* 21 */ 0x229, + /* 22 */ 0x129, + /* 23 */ 0x719, + /* 24 */ 0x0a9, + /* 25 */ 0x699, + /* 26 */ 0x599, + /* 27 */ 0x479, + /* 28 */ 0x069, + /* 29 */ 0x659, + /* 2a */ 0x559, + /* 2b */ 0x749, + /* 2c */ 0x4d9, + /* 2d */ 0x6c9, + /* 2e */ 0x5c9, + /* 2f */ 0x289, + /* 30 */ 0x249, + /* 31 */ 0x639, + /* 32 */ 0x539, + /* 33 */ 0x729, + /* 34 */ 0x4b9, + /* 35 */ 0x6a9, + /* 36 */ 0x5a9, + /* 37 */ 0x059, + /* 38 */ 0x0c9, + /* 39 */ 0x669, + /* 3a */ 0x569, + /* 3b */ 0x099, + /* 3c */ 0x4e9, + /* 3d */ 0x119, + /* 3e */ 0x219, + /* 3f */ 0x149, + /* 40 */ 0x185, + /* 41 */ 0x225, + /* 42 */ 0x125, + /* 43 */ 0x715, + /* 44 */ 0x0a5, + /* 45 */ 0x695, + /* 46 */ 0x595, + /* 47 */ 0x475, + /* 48 */ 0x065, + /* 49 */ 0x655, + /* 4a */ 0x555, + /* 4b */ 0x745, + /* 4c */ 0x4d5, + /* 4d */ 0x6c5, + /* 4e */ 0x5c5, + /* 4f */ 0x285, + /* 50 */ 0x245, + /* 51 */ 0x635, + /* 52 */ 0x535, + /* 53 */ 0x725, + /* 54 */ 0x4b5, + /* 55 */ 0x6a5, + /* 56 */ 0x5a5, + /* 57 */ 0x055, + /* 58 */ 0x0c5, + /* 59 */ 0x665, + /* 5a */ 0x565, + /* 5b */ 0x095, + /* 5c */ 0x4e5, + /* 5d */ 0x115, + /* 5e */ 0x215, + /* 5f */ 0x145, + /* 60 */ 0x18c, + /* 61 */ 0x22c, + /* 62 */ 0x12c, + /* 63 */ 0x713, + /* 64 */ 0x0ac, + /* 65 */ 0x693, + /* 66 */ 0x593, + /* 67 */ 0x473, + /* 68 */ 0x06c, + /* 69 */ 0x653, + /* 6a */ 0x553, + /* 6b */ 0x743, + /* 6c */ 0x4d3, + /* 6d */ 0x6c3, + /* 6e */ 0x5c3, + /* 6f */ 0x28c, + /* 70 */ 0x24c, + /* 71 */ 0x633, + /* 72 */ 0x533, + /* 73 */ 0x723, + /* 74 */ 0x4b3, + /* 75 */ 0x6a3, + /* 76 */ 0x5a3, + /* 77 */ 0x05c, + /* 78 */ 0x0cc, + /* 79 */ 0x663, + /* 7a */ 0x563, + /* 7b */ 0x09c, + /* 7c */ 0x4e3, + /* 7d */ 0x11c, + /* 7e */ 0x21c, + /* 7f */ 0x14c, + /* 80 */ 0x58d, + /* 81 */ 0x62d, + /* 82 */ 0x52d, + /* 83 */ 0x312, + /* 84 */ 0x4ad, + /* 85 */ 0x292, + /* 86 */ 0x192, + /* 87 */ 0x072, + /* 88 */ 0x46d, + /* 89 */ 0x252, + /* 8a */ 0x152, + /* 8b */ 0x342, + /* 8c */ 0x0d2, + /* 8d */ 0x2c2, + /* 8e */ 0x1c2, + /* 8f */ 0x68d, + /* 90 */ 0x64d, + /* 91 */ 0x232, + /* 92 */ 0x132, + /* 93 */ 0x322, + /* 94 */ 0x0b2, + /* 95 */ 0x2a2, + /* 96 */ 0x1a2, + /* 97 */ 0x45d, + /* 98 */ 0x4cd, + /* 99 */ 0x262, + /* 9a */ 0x162, + /* 9b */ 0x49d, + /* 9c */ 0x0e2, + /* 9d */ 0x51d, + /* 9e */ 0x61d, + /* 9f */ 0x54d, + /* a0 */ 0x18a, + /* a1 */ 0x22a, + /* a2 */ 0x12a, + /* a3 */ 0x71a, + /* a4 */ 0x0aa, + /* a5 */ 0x69a, + /* a6 */ 0x59a, + /* a7 */ 0x47a, + /* a8 */ 0x06a, + /* a9 */ 0x65a, + /* aa */ 0x55a, + /* ab */ 0x74a, + /* ac */ 0x4da, + /* ad */ 0x6ca, + /* ae */ 0x5ca, + /* af */ 0x28a, + /* b0 */ 0x24a, + /* b1 */ 0x63a, + /* b2 */ 0x53a, + /* b3 */ 0x72a, + /* b4 */ 0x4ba, + /* b5 */ 0x6aa, + /* b6 */ 0x5aa, + /* b7 */ 0x05a, + /* b8 */ 0x0ca, + /* b9 */ 0x66a, + /* ba */ 0x56a, + /* bb */ 0x09a, + /* bc */ 0x4ea, + /* bd */ 0x11a, + /* be */ 0x21a, + /* bf */ 0x14a, + /* c0 */ 0x186, + /* c1 */ 0x226, + /* c2 */ 0x126, + /* c3 */ 0x716, + /* c4 */ 0x0a6, + /* c5 */ 0x696, + /* c6 */ 0x596, + /* c7 */ 0x476, + /* c8 */ 0x066, + /* c9 */ 0x656, + /* ca */ 0x556, + /* cb */ 0x746, + /* cc */ 0x4d6, + /* cd */ 0x6c6, + /* ce */ 0x5c6, + /* cf */ 0x286, + /* d0 */ 0x246, + /* d1 */ 0x636, + /* d2 */ 0x536, + /* d3 */ 0x726, + /* d4 */ 0x4b6, + /* d5 */ 0x6a6, + /* d6 */ 0x5a6, + /* d7 */ 0x056, + /* d8 */ 0x0c6, + /* d9 */ 0x666, + /* da */ 0x566, + /* db */ 0x096, + /* dc */ 0x4e6, + /* dd */ 0x116, + /* de */ 0x216, + /* df */ 0x146, + /* e0 */ 0x58e, + /* e1 */ 0x62e, + /* e2 */ 0x52e, + /* e3 */ 0x311, + /* e4 */ 0x4ae, + /* e5 */ 0x291, + /* e6 */ 0x191, + /* e7 */ 0x071, + /* e8 */ 0x46e, + /* e9 */ 0x251, + /* ea */ 0x151, + /* eb */ 0x348, + /* ec */ 0x0d1, + /* ed */ 0x2c8, + /* ee */ 0x1c8, + /* ef */ 0x68e, + /* f0 */ 0x64e, + /* f1 */ 0x231, + /* f2 */ 0x131, + /* f3 */ 0x321, + /* f4 */ 0x0b1, + /* f5 */ 0x2a1, + /* f6 */ 0x1a1, + /* f7 */ 0x45e, + /* f8 */ 0x4ce, + /* f9 */ 0x261, + /* fa */ 0x161, + /* fb */ 0x49e, + /* fc */ 0x0e1, + /* fd */ 0x51e, + /* fe */ 0x61e, + /* ff */ 0x54e, + } }; + + +// GF Antilog lookup table table +static unsigned char CCSDS_alpha_to[NN+1] = { +0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80,0x87,0x89,0x95,0xad,0xdd,0x3d,0x7a,0xf4, +0x6f,0xde,0x3b,0x76,0xec,0x5f,0xbe,0xfb,0x71,0xe2,0x43,0x86,0x8b,0x91,0xa5,0xcd, +0x1d,0x3a,0x74,0xe8,0x57,0xae,0xdb,0x31,0x62,0xc4,0x0f,0x1e,0x3c,0x78,0xf0,0x67, +0xce,0x1b,0x36,0x6c,0xd8,0x37,0x6e,0xdc,0x3f,0x7e,0xfc,0x7f,0xfe,0x7b,0xf6,0x6b, +0xd6,0x2b,0x56,0xac,0xdf,0x39,0x72,0xe4,0x4f,0x9e,0xbb,0xf1,0x65,0xca,0x13,0x26, +0x4c,0x98,0xb7,0xe9,0x55,0xaa,0xd3,0x21,0x42,0x84,0x8f,0x99,0xb5,0xed,0x5d,0xba, +0xf3,0x61,0xc2,0x03,0x06,0x0c,0x18,0x30,0x60,0xc0,0x07,0x0e,0x1c,0x38,0x70,0xe0, +0x47,0x8e,0x9b,0xb1,0xe5,0x4d,0x9a,0xb3,0xe1,0x45,0x8a,0x93,0xa1,0xc5,0x0d,0x1a, +0x34,0x68,0xd0,0x27,0x4e,0x9c,0xbf,0xf9,0x75,0xea,0x53,0xa6,0xcb,0x11,0x22,0x44, +0x88,0x97,0xa9,0xd5,0x2d,0x5a,0xb4,0xef,0x59,0xb2,0xe3,0x41,0x82,0x83,0x81,0x85, +0x8d,0x9d,0xbd,0xfd,0x7d,0xfa,0x73,0xe6,0x4b,0x96,0xab,0xd1,0x25,0x4a,0x94,0xaf, +0xd9,0x35,0x6a,0xd4,0x2f,0x5e,0xbc,0xff,0x79,0xf2,0x63,0xc6,0x0b,0x16,0x2c,0x58, +0xb0,0xe7,0x49,0x92,0xa3,0xc1,0x05,0x0a,0x14,0x28,0x50,0xa0,0xc7,0x09,0x12,0x24, +0x48,0x90,0xa7,0xc9,0x15,0x2a,0x54,0xa8,0xd7,0x29,0x52,0xa4,0xcf,0x19,0x32,0x64, +0xc8,0x17,0x2e,0x5c,0xb8,0xf7,0x69,0xd2,0x23,0x46,0x8c,0x9f,0xb9,0xf5,0x6d,0xda, +0x33,0x66,0xcc,0x1f,0x3e,0x7c,0xf8,0x77,0xee,0x5b,0xb6,0xeb,0x51,0xa2,0xc3,0x00, +}; + +// GF log lookup table. Special value represents log(0) +static unsigned char CCSDS_index_of[NN+1] = { + A0, 0, 1, 99, 2,198,100,106, 3,205,199,188,101,126,107, 42, + 4,141,206, 78,200,212,189,225,102,221,127, 49,108, 32, 43,243, + 5, 87,142,232,207,172, 79,131,201,217,213, 65,190,148,226,180, +103, 39,222,240,128,177, 50, 53,109, 69, 33, 18, 44, 13,244, 56, + 6,155, 88, 26,143,121,233,112,208,194,173,168, 80,117,132, 72, +202,252,218,138,214, 84, 66, 36,191,152,149,249,227, 94,181, 21, +104, 97, 40,186,223, 76,241, 47,129,230,178, 63, 51,238, 54, 16, +110, 24, 70,166, 34,136, 19,247, 45,184, 14, 61,245,164, 57, 59, + 7,158,156,157, 89,159, 27, 8,144, 9,122, 28,234,160,113, 90, +209, 29,195,123,174, 10,169,145, 81, 91,118,114,133,161, 73,235, +203,124,253,196,219, 30,139,210,215,146, 85,170, 67, 11, 37,175, +192,115,153,119,150, 92,250, 82,228,236, 95, 74,182,162, 22,134, +105,197, 98,254, 41,125,187,204,224,211, 77,140,242, 31, 48,220, +130,171,231, 86,179,147, 64,216, 52,176,239, 38, 55, 12, 17, 68, +111,120, 25,154, 71,116,167,193, 35, 83,137,251, 20, 93,248,151, + 46, 75,185, 96, 15,237, 62,229,246,135,165, 23, 58,163, 60,183, +}; + +// Only half the coefficients are given here because the +// generator polynomial is palindromic; G0 = G32, G1 = G31, etc. +// Only G16 is unique +static unsigned char CCSDS_poly[] = { + 0,249, 59, 66, 4, 43,126,251, 97, 30, 3,213, 50, 66,170, 5, + 24, +}; + +static inline int modnn(int x){ + while (x >= NN) { + x -= NN; + x = (x >> 8) + (x & NN); + } + return x; +} + +// Update Reed-Solomon encoder +// parity -> 32-byte reed-solomon encoder state; clear this to zero before each frame +void update_rs( + unsigned char parity[32], // 32-byte encoder state; zero before each frame + unsigned char c) // Current data byte to update +{ + unsigned char feedback; + int j,t; + + assert(parity != NULL); + feedback = CCSDS_index_of[c ^ parity[0]]; + if(feedback != A0){ // only if feedback is non-zero + // Take advantage of palindromic polynomial to halve the multiplies + // Do G1...G15, which is the same as G17...G31 + for(j=1;j<(int)(NP/2);j++){ + t = CCSDS_alpha_to[modnn(feedback + CCSDS_poly[j])]; + parity[j] ^= t; + parity[NP-j] ^= t; + } + // Do G16, which is used in only parity[16] + t = CCSDS_alpha_to[modnn(feedback + CCSDS_poly[j])]; + parity[j] ^= t; + } + // shift left + memmove(&parity[0],&parity[1],NP-1); + // G0 is 1 in alpha form, 0 in index form; don't need to multiply by it + parity[NP-1] = CCSDS_alpha_to[feedback]; + //taskYIELD(); +} + +#define SYNC (0x0fa) // K.28.5, RD=-1 + +void write_little_endian(unsigned int word, int num_bytes, FILE *wav_file) +{ + unsigned buf; + while(num_bytes>0) + { buf = word & 0xff; + fwrite(&buf, 1,1, wav_file); + num_bytes--; + word >>= 8; + } +}