Enable Telemetry on DumbRC receivers (#1111)

Tested with X6FGv1.1, X6FP, X6DC(G)v1.1

I also tested with multiple X6F receivers and some gave RSSI Telem and some gave nothing.
2 of them had the same PCB as the X6FP and neither gave telemetry.
I had a third with the same PCB with the X6FP which did give RSSI
and of my two with an older PCB one gives RSSI telem and the other does not.

Of the receivers I tried only one set packet_in[6] to match the TX packet[1] and it was the
oldest receiver of the ones I own.

Multiprotocol/RadioLink_cc2500.ino

@@ -232,7 +232,7 @@ static void __attribute__((unused)) RLINK_send_packet()
 			packet[1] |= 0x21;					//air 0x21 on dump but it looks to support telemetry at least RSSI
 			break;
 		case RLINK_DUMBORC:
-			packet[1]  = 0x00;					//always 0x00 on dump
+			packet[1] |= 0x01;					//always 0x00 on dump but does appear to support telemtry on newer transmitters
 			break;
 	}
 	
@@ -384,8 +384,9 @@ uint16_t RLINK_callback()
 					debug("Telem:");
 				#endif
 				CC2500_ReadData(packet_in, len);
-				if(packet_in[0]==RLINK_RX_PACKET_LEN && (packet_in[len-1] & 0x80) && memcmp(&packet[2],rx_tx_addr,RLINK_TX_ID_LEN)==0 && packet_in[6]==packet[1])
+				if(packet_in[0]==RLINK_RX_PACKET_LEN && (packet_in[len-1] & 0x80) && memcmp(&packet[2],rx_tx_addr,RLINK_TX_ID_LEN)==0 && (packet_in[6]==packet[1] || sub_protocol == RLINK_DUMBORC))
 				{//Correct telemetry received: length, CRC, ID and type
+				 //packet_in[6] is 0x00 on almost all DumboRC RX so assume it is always valid
 					#ifdef RLINK_DEBUG_TELEM
 						for(uint8_t i=0;i<len;i++)
 							debug(" %02X",packet_in[i]);

Multiprotocol/SGF22_nrf24l01.ino

@@ -169,6 +169,7 @@ uint16_t SGF22_callback()
 {
 	#ifdef SGF22_HUB_TELEMETRY
 		bool rx = false;
+		static uint8_t telem_count = 0;
 	#endif
 
 	switch(phase)
@@ -195,6 +196,8 @@ uint16_t SGF22_callback()
 				{//packets: 00 0B 00 -> 00 0B 01
 					telemetry_link = 1;
 					v_lipo1 = packet_in[2] ? 0 : 255;	//2.9V for 1S, 7.0V for 2S
+					telemetry_lost = 0;
+					telem_count = 0;
 				}
 				#if 0
 					debug("L %d ",p_len);
@@ -204,6 +207,20 @@ uint16_t SGF22_callback()
 					debugln("");
 				#endif
 			}
+			if(telem_count > 4*63)				// Around 3.5sec with no telemetry
+				telemetry_lost = 1;
+			else
+			{
+				telem_count++;
+				if(!telemetry_lost && (telem_count & 0x3F) == 0)
+				{// Should have received a telem packet but... Send telem to the radio to keep it alive
+					telemetry_link = 1;
+					#if 0
+						debugln("Miss");
+					#endif
+				}
+			}
+
 	#endif
 			phase++;
 			break;
@@ -245,6 +262,7 @@ void SGF22_init()
 	phase = SGF22_DATA1;
 	#ifdef SGF22_HUB_TELEMETRY
 		RX_RSSI = 100;		// Dummy value
+		telemetry_lost = 1;
 	#endif
 }
 

Multiprotocol/V761_nrf24l01.ino

@@ -244,7 +244,7 @@ uint16_t V761_callback()
 			else
 			{
 				packet_count++;
-				if(!telemetry_lost && !rx && (packet_count%64) == 0)
+				if(!telemetry_lost && !rx && (packet_count & 0x3F) == 0)
 				{// Should have received a telem packet but... Send telem to the radio to keep it alive
 					telemetry_link = 1;
 					#ifdef V761_TELEM_DEBUG

Protocols_Details.md

@@ -62,7 +62,7 @@ You've upgraded the module but the radio does not display the name of the protoc
 # Available Protocol Table of Contents (Listed Alphabetically)
 
 Protocol Name|Build|Protocol Number|Sub_Proto 0|Sub_Proto 1|Sub_Proto 2|Sub_Proto 3|Sub_Proto 4|Sub_Proto 5|Sub_Proto 6|Sub_Proto 7|RF Module|Emulation
----|---|---|---|---|---|---|---|---|---|---|---
+---|---|---|---|---|---|---|---|---|---|---|---|---
 [Assan](Protocols_Details.md#ASSAN---24)|AIR/SFC|24|||||||||NRF24L01|
 [Bayang](Protocols_Details.md#BAYANG---14)|AIR/SFC|14|Bayang|H8S3D|X16_AH|IRDRONE|DHD_D4|QX100|||NRF24L01|XN297
 [Bayang RX](Protocols_Details.md#BAYANG-RX---59)|AIR/SFC|59|Multi|CPPM|||||||NRF24L01|XN297