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POCSAG TX: Support for numeric only and address only messages

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This commit is contained in:
furrtek 2017-02-08 01:19:29 +00:00
parent c72b490d49
commit 21de81bb85
7 changed files with 179 additions and 72 deletions
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128
firmware/common/pocsag.cpp
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@ -76,17 +76,43 @@ void insert_BCH(BCHCode& BCH_code, uint32_t * codeword) {
// Even parity
(*codeword) |= (parity & 1);
}
uint32_t get_digit_code(char code) {
if ((code >= '0') && (code <= '9')) {
code -= '0';
} else {
if (code == 'S')
code = 10;
else if (code == 'U')
code = 11;
else if (code == ' ')
code = 12;
else if (code == '-')
code = 13;
else if (code == ']')
code = 14;
else if (code == '[')
code = 15;
else
code = 12;
}
code = ((code & 0x0C) >> 2) | ((code & 0x03) << 2); // ----3210 -> ----1032
code = ((code & 0x0A) >> 1) | ((code & 0x05) << 1); // ----1032 -> ----0123
return code;
}
void pocsag_encode(
BCHCode& BCH_code, const std::string text, const uint32_t address,
const MessageType type, BCHCode& BCH_code, const std::string message, const uint32_t address,
std::vector<uint32_t>& codewords) {
size_t b, c, address_slot;
size_t bit_idx, char_idx = 0;
uint32_t codeword;
uint32_t codeword, digit_code;
char ascii_char;
size_t text_size = text.size();
size_t message_size = message.size();
// Preamble
for (b = 0; b < (POCSAG_PREAMBLE_LENGTH / 32); b++) {
@ -97,7 +123,8 @@ void pocsag_encode(
codeword = (address & 0x1FFFF8U) << 10;
address_slot = (address & 7) * 2;
// Function
codeword |= (3 << 11);
if (type == MessageType::ALPHANUMERIC)
codeword |= (3 << 11);
insert_BCH(BCH_code, &codeword);
@ -106,11 +133,13 @@ void pocsag_encode(
for (c = 0; c < 16; c++) {
if (c == address_slot) {
codewords.push_back(codeword);
break;
if (type != MessageType::ADDRESS_ONLY) break;
} else
codewords.push_back(POCSAG_IDLEWORD);
}
if (type == MessageType::ADDRESS_ONLY) return; // Done.
codeword = 0;
bit_idx = 20 + 11;
@ -120,49 +149,76 @@ void pocsag_encode(
for ( ; c < 16; c++) {
if (char_idx < text_size) {
// Fill up 20 bits
do {
bit_idx -= 7;
// Fill up 20 bits
if (type == MessageType::ALPHANUMERIC) {
if ((char_idx < message_size) || (ascii_char)) {
do {
bit_idx -= 7;
if (char_idx < message_size)
ascii_char = message[char_idx] & 0x7F;
else
ascii_char = 0; // Codeword padding
// Bottom's up
ascii_char = (ascii_char & 0xF0) >> 4 | (ascii_char & 0x0F) << 4; // *6543210 -> 3210*654
ascii_char = (ascii_char & 0xCC) >> 2 | (ascii_char & 0x33) << 2; // 3210*654 -> 103254*6
ascii_char = (ascii_char & 0xAA) >> 2 | (ascii_char & 0x55); // 103254*6 -> *0123456
codeword |= (ascii_char << bit_idx);
char_idx++;
} while (bit_idx > 11);
if (char_idx < text_size)
ascii_char = text[char_idx] & 0x7F;
else
ascii_char = 0; // Codeword padding
codeword &= 0x7FFFF800; // Trim data
codeword |= 0x80000000; // Message type
insert_BCH(BCH_code, &codeword);
// Bottom's up
ascii_char = (ascii_char & 0xF0) >> 4 | (ascii_char & 0x0F) << 4; // *6543210 -> 3210*654
ascii_char = (ascii_char & 0xCC) >> 2 | (ascii_char & 0x33) << 2; // 3210*654 -> 103254*6
ascii_char = (ascii_char & 0xAA) >> 2 | (ascii_char & 0x55); // 103254*6 -> *0123456
codewords.push_back(codeword);
codeword |= (ascii_char << bit_idx);
char_idx++;
} while (bit_idx > 11);
codeword &= 0x7FFFF800; // Trim data
codeword |= 0x80000000; // Message type
insert_BCH(BCH_code, &codeword);
codewords.push_back(codeword);
if (bit_idx != 11) {
bit_idx = 20 + bit_idx;
codeword = ascii_char << bit_idx;
if (bit_idx != 11) {
bit_idx = 20 + bit_idx;
codeword = ascii_char << bit_idx;
} else {
bit_idx = 20 + 11;
codeword = 0;
}
} else {
codewords.push_back(POCSAG_IDLEWORD); // Batch padding
}
} else if (type == MessageType::NUMERIC_ONLY) {
if (char_idx < message_size) {
do {
bit_idx -= 4;
if (char_idx < message_size)
digit_code = get_digit_code(message[char_idx]);
else
digit_code = 3; // Space (codeword padding)
codeword |= (digit_code << bit_idx);
char_idx++;
} while (bit_idx > 11);
codeword |= 0x80000000; // Message type
insert_BCH(BCH_code, &codeword);
codewords.push_back(codeword);
bit_idx = 20 + 11;
codeword = 0;
} else {
codewords.push_back(POCSAG_IDLEWORD); // Batch padding
}
} else {
codewords.push_back(POCSAG_IDLEWORD); // Batch padding
}
}
c = 0;
} while (char_idx < text_size);
} while (char_idx < message_size);
}
bool pocsag_decode_batch(const POCSAGPacket& batch, POCSAGState * const state) {