DIY-Multiprotocol-TX-Module/Multiprotocol/Corona_cc2500.ino

/*
 This project 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 3 of the License, or
 (at your option) any later version.

 Multiprotocol 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 Multiprotocol.  If not, see <http://www.gnu.org/licenses/>.
 */

#if defined(CORONA_CC2500_INO)

#include "iface_cc2500.h"

//#define CORONA_FORCE_ID

#define CORONA_RF_NUM_CHANNELS	3
#define CORONA_ADDRESS_LENGTH	4
#define CORONA_BIND_CHANNEL_V1	0xD1	// also Flydream V3
#define CORONA_BIND_CHANNEL_V2	0xB8
#define CORONA_COARSE			0x00
#define FDV3_BIND_PERIOD		5000
#define FDV3_CHANNEL_PERIOD		4000

const PROGMEM uint8_t CORONA_init_values[] = {
  /* 00 */ 0x29, 0x2E, 0x06, 0x07, 0xD3, 0x91, 0xFF, 0x04,
  /* 08 */ 0x05, 0x00, CORONA_BIND_CHANNEL_V1, 0x06, 0x00, 0x5C, 0x4E, 0xC4 + CORONA_COARSE,
  /* 10 */ 0x5B, 0xF8, 0x03, 0x23, 0xF8, 0x47, 0x07, 0x30,
  /* 18 */ 0x18, 0x16, 0x6C, 0x43, 0x40, 0x91, 0x87, 0x6B,
  /* 20 */ 0xF8, 0x56, 0x10, 0xA9, 0x0A, 0x00, 0x11, 0x41,
  /* 28 */ 0x00, 0x59, 0x7F, 0x3F, 0x81, 0x35, 0x0B
};

uint8_t fdv3_id_send;

static void __attribute__((unused)) CORONA_rf_init()
{
	CC2500_Strobe(CC2500_SIDLE);

	for (uint8_t i = 0; i <= 0x2E; ++i)
		CC2500_WriteReg(i, pgm_read_byte_near(&CORONA_init_values[i]));
	if(sub_protocol==COR_V2)
	{
		CC2500_WriteReg(CC2500_0A_CHANNR, CORONA_BIND_CHANNEL_V2);
		CC2500_WriteReg(CC2500_0E_FREQ1, 0x80);
		CC2500_WriteReg(CC2500_0F_FREQ0, 0x00 + CORONA_COARSE);
		CC2500_WriteReg(CC2500_15_DEVIATN, 0x50);
		CC2500_WriteReg(CC2500_17_MCSM1, 0x00);
	    CC2500_WriteReg(CC2500_1B_AGCCTRL2, 0x67);
		CC2500_WriteReg(CC2500_1C_AGCCTRL1, 0xFB);
		CC2500_WriteReg(CC2500_1D_AGCCTRL0, 0xDC);
	}
	else if(sub_protocol==FD_V3)
	{
		// Flydream receiver captures have deviation 50, tx captures show 47
		CC2500_WriteReg(CC2500_15_DEVIATN, 0x50);
	}
	
	CC2500_WriteReg(CC2500_0C_FSCTRL0, option);

	//not sure what they are doing to the PATABLE since basically only the first byte is used and it's only 8 bytes long. So I think they end up filling the PATABLE fully with 0xFF
	CC2500_WriteRegisterMulti(CC2500_3E_PATABLE,(const uint8_t *)"\x08\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF", 13);

	CC2500_SetTxRxMode(TX_EN);
	CC2500_SetPower();
}

// Generate id and hopping freq
static void __attribute__((unused)) CORONA_TXID_init()
{
	#ifdef CORONA_FORCE_ID
		// Example of ID and channels taken from dumps
		switch(sub_protocol)
		{
			case COR_V1:
				memcpy((void *)rx_tx_addr,(void *)"\x1F\xFE\x6C\x35",CORONA_ADDRESS_LENGTH);
				memcpy((void *)hopping_frequency,(void *)"\x17\x0D\x03\x49",CORONA_RF_NUM_CHANNELS+1);
				break;
			case COR_V2:
				memcpy((void *)rx_tx_addr,(void *)"\xFE\xFE\x02\xFB",CORONA_ADDRESS_LENGTH);
				memcpy((void *)hopping_frequency,(void *)"\x14\x3D\x35",CORONA_RF_NUM_CHANNELS);
			case FD_V3:
				memcpy((void *)rx_tx_addr,(void *)"\x02\xFA\x38\x38",CORONA_ADDRESS_LENGTH);
				memcpy((void *)hopping_frequency,(void *)"\x71\xB9\x30",CORONA_RF_NUM_CHANNELS);
				break;
	}
	#else
		// From dumps channels are anything between 0x00 and 0xC5 on V1.
		// But 0x00 and 0xB8 should be avoided on V2 since they are used for bind.
		// Below code make sure channels are between 0x02 and 0xA0, spaced with
		// a minimum of 2 and not ordered (RX only use the 1st channel unless there is an issue).
		// Extra hopping frequency used for Flydream V3 id packets.
		uint8_t order=rx_tx_addr[3]&0x03;
		for(uint8_t i=0; i<CORONA_RF_NUM_CHANNELS+1; i++)
			hopping_frequency[i^order]=2+rx_tx_addr[3-i]%39+(i<<5)+(i<<3);

		if(sub_protocol!=FD_V3)
		{
			// ID looks random but on the 15 V1 dumps they all show the same odd/even rule
			if(rx_tx_addr[3]&0x01)
			{	// If [3] is odd then [0] is odd and [2] is even 
				rx_tx_addr[0]|=0x01;
				rx_tx_addr[2]&=0xFE;
			}
			else
			{	// If [3] is even then [0] is even and [2] is odd 
				rx_tx_addr[0]&=0xFE;
				rx_tx_addr[2]|=0x01;
			}
			rx_tx_addr[1]=0xFE;			// Always FE in the dumps of V1 and V2
		}
		else
		{
			rx_tx_addr[1]=0xFA;			// Always FA for Flydream V3
			rx_tx_addr[3]=hopping_frequency[CORONA_RF_NUM_CHANNELS];	// channel used for id/freq packets
		}
	#endif
}

static uint16_t __attribute__((unused)) CORONA_build_bind_pkt()
{
	if(sub_protocol==COR_V1)
	{	// V1
		if(bind_counter&1)
		{ // Send TX ID
			packet[0]=0x04;		// 5 bytes to follow
			for(uint8_t i=0; i<CORONA_ADDRESS_LENGTH; i++)
				packet[i+1]=rx_tx_addr[i];
			packet[5]=0xCD;		// Unknown but seems to be always the same value for V1
			return 3689;
		}
		else
		{ // Send hopping freq
			packet[0]=0x03;		// 4 bytes to follow
			for(uint8_t i=0; i<CORONA_RF_NUM_CHANNELS+1; i++)
				packet[i+1]=hopping_frequency[i];
			// Only the first 3 channels of hopping_frequency used for data
			return 3438;
		}
	}
	else
	{	// V2 and FDV3
		packet[0]=0x04;		// 5 bytes to follow
		for(uint8_t i=0; i<CORONA_ADDRESS_LENGTH; i++)
			packet[i+1]=rx_tx_addr[i];
		packet[5]=0x00;		// Unknown but seems to be always the same value for V2 and FDV3
		if(sub_protocol==FD_V3)
			return FDV3_BIND_PERIOD;
		else
			return 26791;
	}
}

// 8 Channels with direct values from PPM
static uint16_t __attribute__((unused)) CORONA_build_packet()
{
	CC2500_SetPower();
	if(state && sub_protocol==COR_V2)
	{	// Send identifier packet for 2.65sec. This is how the RX learns the hopping table after a bind. Why it's not part of the bind like V1 is a mistery...
		// Set channel
		CC2500_WriteReg(CC2500_0A_CHANNR, 0x00);
		state--;
		packet[0]=0x07;		// 8 bytes to follow
		// Send hopping freq
		for(uint8_t i=0; i<CORONA_RF_NUM_CHANNELS; i++)
			packet[i+1]=hopping_frequency[i];
		// Send TX ID
		for(uint8_t i=0; i<CORONA_ADDRESS_LENGTH; i++)
			packet[i+4]=rx_tx_addr[i];
		packet[8]=0;
		return 6647;
	}

	// Flydream every fourth packet is identifier packet and is on channel number
	// that is last byte of rx_tx_addr
	if (fdv3_id_send)
	{
		fdv3_id_send = 0;
		CC2500_WriteReg(CC2500_0A_CHANNR, rx_tx_addr[CORONA_ADDRESS_LENGTH-1]);
		packet[0] = 0x07;   // 8 bytes to follow
		// Send TX ID
		for(uint8_t i = 0; i < CORONA_ADDRESS_LENGTH; i++)
			packet[i+1] = rx_tx_addr[i];
		// Send hopping freq
		for(uint8_t i = 0; i < CORONA_RF_NUM_CHANNELS; i++)
			packet[i+1+CORONA_ADDRESS_LENGTH] = hopping_frequency[i];
		packet[8] = 0;
		return 2*FDV3_CHANNEL_PERIOD;  // extra delay after id packet according to captures
	}

	// Set RF channel
	CC2500_WriteReg(CC2500_0A_CHANNR, hopping_frequency[hopping_frequency_no]);

	// Build packet
	packet[0] = 0x10;   // 17 bytes to follow

	// Channels
	memset(packet+9, 0x00, 4);
	for (uint8_t i=0; i<8; i++)
	{ // Channel values are packed
		uint16_t val=convert_channel_ppm(i);
		packet[i+1] = val;
		packet[9 + (i>>1)] |= (i&0x01)?(val>>4)&0xF0:(val>>8)&0x0F;
	}

	// TX ID
	for (uint8_t i=0; i < CORONA_ADDRESS_LENGTH; i++)
		packet[i+13] = rx_tx_addr[i];

	packet[17] = 0x00;

	if (sub_protocol!=FD_V3)
	{
		// Packet period is based on hopping
		switch (hopping_frequency_no)
		{
			case 0:
				packet_period = sub_protocol == COR_V1
				? 4991
				: 4248;
				break;
			case 1: 
				packet_period = sub_protocol == COR_V1
				? 4991
				: 4345;
				break;
			case 2: 
				packet_period = sub_protocol == COR_V1
				? 12520
				: 13468;
				if (sub_protocol == COR_V2)
					packet[17] = 0x03;
				break;
		}
	}
	hopping_frequency_no++;

	if (sub_protocol == FD_V3)
	{
		if (hopping_frequency_no == CORONA_RF_NUM_CHANNELS)
		{
			fdv3_id_send = 1;
			packet_period = 6000; // extra delay before id packet according to captures
		}
		else
			packet_period = FDV3_CHANNEL_PERIOD;
	}

	hopping_frequency_no %= CORONA_RF_NUM_CHANNELS;
	return packet_period;
}

uint16_t CORONA_callback()
{
	#ifdef MULTI_SYNC
		telemetry_set_input_sync(22000);
	#endif
	// Tune frequency if it has been changed
	CC2500_SetFreqOffset();

	if(IS_BIND_IN_PROGRESS)
	{
		if (bind_counter-- == 0) BIND_DONE;
		packet_period=CORONA_build_bind_pkt();
	}
	else
		packet_period=CORONA_build_packet();

	// Send packet
	CC2500_WriteData(packet, packet[0]+2);
	return packet_period;
}

void CORONA_init()
{
	switch(sub_protocol)
	{
		case COR_V1:
			bind_counter=1400;		// Stay in bind mode for 5s
			break;
		case COR_V2:
			bind_counter=187;		// Stay in bind mode for 5s
			break;
		case FD_V3:
			bind_counter = 2000;	// Stay in bind mode for 10s
			break;
	}
	state=400;					// Used by V2 to send RF channels + ID for 2.65s at startup
	hopping_frequency_no=0;
	fdv3_id_send = 0;
	CORONA_TXID_init();
	CORONA_rf_init();
}

#endif