Added Shenqi protocol and LT8910 emulation layer

Multiprotocol/NRF24l01_SPI.ino

@@ -409,3 +409,196 @@ void XN297_ReadPayload(uint8_t* msg, uint8_t len)
 }
 
 // End of XN297 emulation
+
+///////////////
+// LT8910 emulation layer
+uint8_t LT8910_buffer[64];
+uint8_t LT8910_buffer_start;
+uint16_t LT8910_buffer_overhead_bits;
+uint8_t LT8910_addr[8];
+uint8_t LT8910_addr_size;
+uint8_t LT8910_Preamble_Len;
+uint8_t LT8910_Tailer_Len;
+uint8_t LT8910_CRC_Initial_Data;
+uint8_t LT8910_Flags;
+#define LT8910_CRC_ON 6
+#define LT8910_SCRAMBLE_ON 5
+#define LT8910_PACKET_LENGTH_EN 4
+#define LT8910_DATA_PACKET_TYPE_1 3
+#define LT8910_DATA_PACKET_TYPE_0 2
+#define LT8910_FEC_TYPE_1 1
+#define LT8910_FEC_TYPE_0 0
+
+void LT8910_Config(uint8_t preamble_len, uint8_t trailer_len, uint8_t flags, uint8_t crc_init)
+{
+	//Preamble 1 to 8 bytes
+	LT8910_Preamble_Len=preamble_len;
+	//Trailer 4 to 18 bits
+	LT8910_Tailer_Len=trailer_len;
+	//Flags
+	// CRC_ON: 1 on, 0 off
+	// SCRAMBLE_ON: 1 on, 0 off
+	// PACKET_LENGTH_EN: 1 1st byte of payload is payload size
+	// DATA_PACKET_TYPE: 00 NRZ, 01 Manchester, 10 8bit/10bit line code, 11 interleave data type
+	// FEC_TYPE: 00 No FEC, 01 FEC13, 10 FEC23, 11 reserved
+	LT8910_Flags=flags;
+	//CRC init constant
+	LT8910_CRC_Initial_Data=crc_init;
+}
+
+void LT8910_SetChannel(uint8_t channel)
+{
+	NRF24L01_WriteReg(NRF24L01_05_RF_CH, channel +2);	//NRF24L01 is 2400+channel but LT8900 is 2402+channel
+}
+
+void LT8910_SetTxRxMode(enum TXRX_State mode)
+{
+	if(mode == TX_EN)
+	{
+		//Switch to TX
+		NRF24L01_SetTxRxMode(TXRX_OFF);
+		NRF24L01_SetTxRxMode(TX_EN);
+		//Disable CRC
+		NRF24L01_WriteReg(NRF24L01_00_CONFIG, (1 << NRF24L01_00_PWR_UP));
+	}
+	else
+		if (mode == RX_EN)
+		{
+			NRF24L01_WriteReg(NRF24L01_02_EN_RXADDR, 0x01);		// Enable data pipe 0 only
+			NRF24L01_WriteReg(NRF24L01_11_RX_PW_P0, 32);
+			//Switch to RX
+			NRF24L01_SetTxRxMode(TXRX_OFF);
+			NRF24L01_FlushRx();
+			NRF24L01_SetTxRxMode(RX_EN);
+			// Disable CRC
+			NRF24L01_WriteReg(NRF24L01_00_CONFIG, (1 << NRF24L01_00_PWR_UP) | (1 << NRF24L01_00_PRIM_RX) );
+		}
+		else
+			NRF24L01_SetTxRxMode(TXRX_OFF);
+}
+
+void LT8910_BuildOverhead()
+{
+	uint8_t pos;
+
+	//Build overhead
+	//preamble
+	memset(LT8910_buffer,LT8910_addr[0]&0x01?0xAA:0x55,LT8910_Preamble_Len-1);
+	pos=LT8910_Preamble_Len-1;
+	//address
+	for(uint8_t i=0;i<LT8910_addr_size;i++)
+	{
+		LT8910_buffer[pos]=bit_reverse(LT8910_addr[i]);
+		pos++;
+	}
+	//trailer
+	memset(LT8910_buffer+pos,(LT8910_buffer[pos-1]&0x01)==0?0xAA:0x55,3);
+	LT8910_buffer_overhead_bits=pos*8+LT8910_Tailer_Len;
+	//nrf address length max is 5
+	pos+=LT8910_Tailer_Len/8;
+	LT8910_buffer_start=pos>5?5:pos;
+}
+
+void LT8910_SetAddress(uint8_t *address,uint8_t addr_size)
+{
+	uint8_t addr[5];
+	
+	//Address size (SyncWord) 2 to 8 bytes, 16/32/48/64 bits
+	LT8910_addr_size=addr_size;
+	memcpy(LT8910_addr,address,LT8910_addr_size);
+
+	//Build overhead
+	LT8910_BuildOverhead();
+
+	//Set NRF RX&TX address based on overhead content
+	NRF24L01_WriteReg(NRF24L01_03_SETUP_AW, LT8910_buffer_start-2);
+	for(uint8_t i=0;i<LT8910_buffer_start;i++)	// reverse bytes order
+		addr[i]=LT8910_buffer[LT8910_buffer_start-i-1];
+	NRF24L01_WriteRegisterMulti(NRF24L01_0A_RX_ADDR_P0,	addr,LT8910_buffer_start);
+	NRF24L01_WriteRegisterMulti(NRF24L01_10_TX_ADDR,	addr,LT8910_buffer_start);
+}
+
+uint8_t LT8910_ReadPayload(uint8_t* msg, uint8_t len)
+{
+	uint8_t i,pos=0,shift,end,buffer[32];
+	unsigned int crc=LT8910_CRC_Initial_Data,a;
+	pos=LT8910_buffer_overhead_bits/8-LT8910_buffer_start;
+	end=pos+len+(LT8910_Flags&_BV(LT8910_PACKET_LENGTH_EN)?1:0)+(LT8910_Flags&_BV(LT8910_CRC_ON)?2:0);
+	//Read payload
+	NRF24L01_ReadPayload(buffer,end+1);
+	//Check address + trail
+	for(i=0;i<pos;i++)
+		if(LT8910_buffer[LT8910_buffer_start+i]!=buffer[i])
+			return 0; // wrong address...
+	//Shift buffer to remove trail bits
+	shift=LT8910_buffer_overhead_bits&0x7;
+	for(i=pos;i<end;i++)
+	{
+		a=(buffer[i]<<8)+buffer[i+1];
+		a<<=shift;
+		buffer[i]=(a>>8)&0xFF;
+	}
+	//Check len
+	if(LT8910_Flags&_BV(LT8910_PACKET_LENGTH_EN))
+	{
+		crc=crc16_update(crc,buffer[pos]);
+		if(bit_reverse(len)!=buffer[pos++])
+			return 0; // wrong len...
+	}
+	//Decode message 
+	for(i=0;i<len;i++)
+	{
+		crc=crc16_update(crc,buffer[pos]);
+		msg[i]=bit_reverse(buffer[pos++]);
+	}
+	//Check CRC
+	if(LT8910_Flags&_BV(LT8910_CRC_ON))
+	{
+		if(buffer[pos++]!=((crc>>8)&0xFF)) return 0;	// wrong CRC...
+		if(buffer[pos]!=(crc&0xFF)) return 0;			// wrong CRC...
+	}
+	//Everything ok
+	return 1;
+}
+
+void LT8910_WritePayload(uint8_t* msg, uint8_t len)
+{
+	unsigned int crc=LT8910_CRC_Initial_Data,a,mask;
+	uint8_t i, pos=0,tmp, buffer[64], pos_final,shift;
+	//Add packet len
+	if(LT8910_Flags&_BV(LT8910_PACKET_LENGTH_EN))
+	{
+		tmp=bit_reverse(len);
+		buffer[pos++]=tmp;
+		crc=crc16_update(crc,tmp);
+	}
+	//Add payload
+	for(i=0;i<len;i++)
+	{
+		tmp=bit_reverse(msg[i]);
+		buffer[pos++]=tmp;
+		crc=crc16_update(crc,tmp);
+	}
+	//Add CRC
+	if(LT8910_Flags&_BV(LT8910_CRC_ON))
+	{
+		buffer[pos++]=crc>>8;
+		buffer[pos++]=crc;
+	}
+	//Shift everything to fit behind the trailer (4 to 18 bits)
+	shift=LT8910_buffer_overhead_bits&0x7;
+	pos_final=LT8910_buffer_overhead_bits/8;
+	mask=~(0xFF<<(8-shift));
+	LT8910_buffer[pos_final+pos]=0xFF;
+	for(i=pos-1;i!=0xFF;i--)
+	{
+		a=buffer[i]<<(8-shift);
+		LT8910_buffer[pos_final+i]=(LT8910_buffer[pos_final+i]&mask>>8)|a>>8;
+		LT8910_buffer[pos_final+i+1]=(LT8910_buffer[pos_final+i+1]&mask)|a;
+	}
+	if(shift)
+		pos++;
+	//Send everything
+	NRF24L01_WritePayload(LT8910_buffer+LT8910_buffer_start,pos_final+pos-LT8910_buffer_start);
+}
+// End of LT8910 emulation