portapack-mayhem/firmware/application/rds.cpp

/*
 * 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"

namespace rds {

uint32_t makeblock(uint32_t blockdata, uint16_t offset) {
    uint16_t CRC = 0;
    uint8_t doinv;
    
    for (uint8_t i = 0; i < 16; i++) {
        doinv = (((blockdata << i) & 0x8000) >> 15) ^ (CRC >> 9);
        if (doinv) CRC ^= 0b0011011100;
        CRC = ((CRC << 1) | doinv) & 0x3FF;
    }
    
    return (blockdata << 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;
}

void make_0B_group(uint32_t 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 char * chars) {

	group[0] = PI_code;
	group[1] = (0x0 << 12) | (1 << 11) | (b2b(TP) << 10) | (PTY << 5) | (b2b(TA) << 4) | (b2b(MS) << 3) | (b2b(DI) << 2) | (C & 3);
	group[2] = PI_code;
	group[3] = (chars[0] << 8) | chars[1];
}

void make_2A_group(uint32_t group[], const uint16_t PI_code, const bool TP, const uint8_t PTY, const bool AB,
							const uint8_t segment, const char * chars) {

	group[0] = PI_code;
	group[1] = (0x0 << 12) | (1 << 11) | (b2b(TP) << 10) | (PTY << 5) | (b2b(AB) << 4) | (segment & 15);
	group[2] = (chars[0] << 8) | chars[1];
	group[3] = (chars[2] << 8) | chars[3];
}

uint16_t gen_PSN(const char * psname, const uint8_t pty) {
	uint8_t c;
	uint32_t group[4][4] = { 0 };

	// 4 groups with 2 PSN characters in each
	make_0B_group(&group[0][0], 0xF849, true, pty, false, true, false, 0, &psname[0]);
	make_0B_group(&group[1][0], 0xF849, true, pty, false, true, false, 1, &psname[2]);
	make_0B_group(&group[2][0], 0xF849, true, pty, false, true, false, 2, &psname[4]);
	make_0B_group(&group[3][0], 0xF849, true, pty, false, true, false, 3, &psname[6]);
	
	/*uint32_t group[4][4] = {
		{
		0b1111100001001001,		//PI
		0b0000110011101000,		//Address
		0b1111100001001001,		//PI
		0b0000000000000000		//Replaced
		},
		
		{
		0b1111100001001001,		//PI
		0b0000110011101001,		//Address
		0b1111100001001001,		//PI
		0b0000000000000000		//Replaced
		},
		
		{
		0b1111100001001001,		//PI
		0b0000110011101010,		//Address
		0b1111100001001001,		//PI
		0b0000000000000000		//Replaced
		},
		
		{
		0b1111100001001001,		//PI
		0b0000110011101011,		//Address
		0b1111100001001001,		//PI
		0b0000000000000000		//Replaced
		},
	};
	
	//Insert PSN data in groups
	group[0][3] = (psname[0] << 8) | psname[1];
	group[1][3] = (psname[2] << 8) | psname[3];
	group[2][3] = (psname[4] << 8) | psname[5];
	group[3][3] = (psname[6] << 8) | psname[7];
	*/
	
	// Generate checkbits for all blocks
	for (c = 0; c < 4; c++) {
		group[c][0] = makeblock(group[c][0], RDS_OFFSET_A);
		group[c][1] = makeblock(group[c][1], RDS_OFFSET_B);
		group[c][2] = makeblock(group[c][2], RDS_OFFSET_Cp);	// C' !
		group[c][3] = makeblock(group[c][3], RDS_OFFSET_D);
	}
	
	// Todo
	//for (c = 0; c < 16; c++)
	//	shared_memory.radio_data[c] = group[c >> 2][c & 3];
	
	return 4 * 4 * 26;
}

uint16_t gen_RadioText(const char * radiotext, const uint8_t pty) {
	size_t c, i;
	uint32_t * group;
	char radiotext_buffer[65] = { 0 };
	uint8_t rtlen, groups;
	
	strcpy(radiotext_buffer, radiotext);
	
	rtlen = strlen(radiotext_buffer);
	
	radiotext_buffer[rtlen] = 0x0D;
	
	// Pad to multiple of 4
	while (rtlen & 3)
		radiotext_buffer[rtlen++] = ' ';

	groups = rtlen >> 2;	// 4 characters per group

	group = (uint32_t*)chHeapAlloc(0x0, 4 * groups * sizeof(uint32_t));

	for (c = 0; c < groups; c++)
		make_2A_group(&group[c << 2], 0xF849, true, pty, false, c, &radiotext_buffer[c * 4]);

	// Generate checkbits
	for (c = 0; c < groups; c++) {
		i = c * 4;
		group[i + 0] = makeblock(group[i + 0], RDS_OFFSET_A);
		group[i + 1] = makeblock(group[i + 1], RDS_OFFSET_B);
		group[i + 2] = makeblock(group[i + 2], RDS_OFFSET_C);
		group[i + 3] = makeblock(group[i + 3], RDS_OFFSET_D);
	}
	
	uint32_t * tx_data_u32 = (uint32_t*)shared_memory.tx_data;
	
	for (c = 0; c < (groups * 4); c++)
		tx_data_u32[c] = group[c];
	
	return groups * 4 * 26;
}

} /* namespace rds */