portapack-mayhem/firmware/application/protocols/rds.cpp
2017-04-18 18:12:32 +01:00

180 lines
6.2 KiB
C++

/*
* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
* Copyright (C) 2016 Furrtek
*
* This file is part of PortaPack.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include "rds.hpp"
#include "portapack_shared_memory.hpp"
// RDS infos:
// One group = 4 blocks = 4 * 26 bits
// One block = 26 bits (16 bits data + 10 bits checkword)
// Sent MSB first
namespace rds {
uint32_t make_block(uint32_t data, uint16_t offset) {
uint16_t CRC = 0;
uint8_t bit;
for (uint8_t i = 0; i < 16; i++) {
bit = (((data << i) & 0x8000) >> 15) ^ (CRC >> 9);
if (bit) CRC ^= 0b0011011100;
CRC = ((CRC << 1) | bit) & 0x3FF;
}
return (data << 10) | (CRC ^ offset);
}
// Todo:
// Make PI
// TA/TP flags
// Group selection
// Boolean to binary
uint8_t b2b(const bool in) {
if (in)
return 1;
else
return 0;
}
// Type 0B groups are like 0A groups but without alternative frequency data
void make_0B_group(RDS_group * group, const uint16_t PI_code, const bool TP, const uint8_t PTY, const bool TA,
const bool MS, const bool DI, const uint8_t C, const std::string chars) {
group->block[0] = PI_code;
group->block[1] = (0x0 << 12) | (1 << 11) | (b2b(TP) << 10) | ((PTY & 0x1F) << 5) | (b2b(TA) << 4) | (b2b(MS) << 3) | (b2b(DI) << 2) | (C & 3);
group->block[2] = PI_code;
group->block[3] = (chars[0] << 8) | chars[1];
}
// For RadioText, up to 64 chars with 2A, 32 chars with 2B
void make_2A_group(RDS_group * group, const uint16_t PI_code, const bool TP, const uint8_t PTY, const bool AB,
const uint8_t segment, const std::string chars) {
group->block[0] = PI_code;
group->block[1] = (0x2 << 12) | (0 << 11) | (b2b(TP) << 10) | ((PTY & 0x1F) << 5) | (b2b(AB) << 4) | (segment & 15);
group->block[2] = (chars[0] << 8) | chars[1];
group->block[3] = (chars[2] << 8) | chars[3];
}
// Time and date - usually one message per minute - Month: 1~12 - Day: 1~31 - Hour/Minute: 0~59 - Local offset: -12/+12 from UTC
void make_4A_group(RDS_group * group, const uint16_t PI_code, const bool TP, const uint8_t PTY,
const uint16_t year, const uint8_t month, const uint8_t day,
const uint8_t hour, const uint8_t minute, const int8_t local_offset) {
uint32_t L = 0;
uint32_t day_code;
if ((month == 1) || (month == 2)) L = 1;
day_code = 14956 + day + (uint32_t)((float)(year - 1900 - L) * 365.25) + uint16_t((float)((month + 1) + L * 12) * 30.6001);
group->block[0] = PI_code;
group->block[1] = (0x4 << 12) | (0 << 11) | (b2b(TP) << 10) | ((PTY & 0x1F) << 5) | ((day_code & 0x18000) >> 15);
group->block[2] = ((day_code & 0x7FFF) << 1) | (hour >> 4);
group->block[3] = ((hour & 15) << 12) | ((minute & 0x3F) << 6) | (local_offset & 0x3F);
}
uint16_t gen_PSN(const std::string & psname, const RDS_flags * rds_flags) {
uint8_t c;
RDS_group groups[4] = { 0 };
// 4 groups with 2 PSN characters in each
for (c = 0; c < 4; c++)
make_0B_group(&groups[c], rds_flags->PI_code, rds_flags->TP, rds_flags->PTY, rds_flags->TA, rds_flags->MS, rds_flags->DI, c, psname.substr(c * 2, 2));
// Generate checkbits for each block of each group
for (c = 0; c < 4; c++) {
groups[c].block[0] = make_block(groups[c].block[0], RDS_OFFSET_A);
groups[c].block[1] = make_block(groups[c].block[1], RDS_OFFSET_B);
groups[c].block[2] = make_block(groups[c].block[2], RDS_OFFSET_Cp); // C' !
groups[c].block[3] = make_block(groups[c].block[3], RDS_OFFSET_D);
}
uint32_t * tx_data_u32 = (uint32_t*)shared_memory.bb_data.data;
// Copy to tx_data for baseband
for (c = 0; c < 4 * 4; c++)
tx_data_u32[c] = groups[c >> 2].block[c & 3];
return 4 * 4 * 26;
}
uint16_t gen_RadioText(const std::string & text, const bool AB, const RDS_flags * rds_flags) {
size_t c;
RDS_group * groups_ptr;
std::string radiotext_buffer = text;
size_t rt_length, groups;
radiotext_buffer += 0x0D;
rt_length = radiotext_buffer.length();
rt_length = (rt_length + 3) & 0xFC;
groups = rt_length >> 2; // 4 characters per group
groups_ptr = (RDS_group*)chHeapAlloc(0, groups * sizeof(RDS_group));
for (c = 0; c < groups; c++)
make_2A_group(&groups_ptr[c], rds_flags->PI_code, rds_flags->TP, rds_flags->PTY, AB, c, radiotext_buffer.substr(c * 4, 4));
// Generate checkbits for each block of each group
for (c = 0; c < groups; c++) {
groups_ptr[c].block[0] = make_block(groups_ptr[c].block[0], RDS_OFFSET_A);
groups_ptr[c].block[1] = make_block(groups_ptr[c].block[1], RDS_OFFSET_B);
groups_ptr[c].block[2] = make_block(groups_ptr[c].block[2], RDS_OFFSET_C);
groups_ptr[c].block[3] = make_block(groups_ptr[c].block[3], RDS_OFFSET_D);
}
uint32_t * tx_data_u32 = (uint32_t*)shared_memory.bb_data.data;
// Copy to tx_data for baseband
for (c = 0; c < groups * 4; c++)
tx_data_u32[c] = groups_ptr[c >> 2].block[c & 3];
chHeapFree(groups_ptr);
return groups * 4 * 26;
}
uint16_t gen_ClockTime(const RDS_flags * rds_flags,
const uint16_t year, const uint8_t month, const uint8_t day,
const uint8_t hour, const uint8_t minute, const int8_t local_offset) {
uint8_t c;
RDS_group group = { 0 };
make_4A_group(&group, rds_flags->PI_code, rds_flags->TP, rds_flags->PTY, year, month, day, hour, minute, local_offset);
// Generate checkbits for each block
group.block[0] = make_block(group.block[0], RDS_OFFSET_A);
group.block[1] = make_block(group.block[1], RDS_OFFSET_B);
group.block[2] = make_block(group.block[2], RDS_OFFSET_C);
group.block[3] = make_block(group.block[3], RDS_OFFSET_D);
uint32_t * tx_data_u32 = (uint32_t*)shared_memory.bb_data.data;
// Copy to tx_data for baseband
for (c = 0; c < 4; c++)
tx_data_u32[c] = group.block[c];
return 4 * 26;
}
} /* namespace rds */