Added a common deadband conversion code

Modified protocols:
 - GD00X applied on aileron
 - KF606 applied on aileron
 - POTENSIC applied on throttle

Multiprotocol/Common.ino

@@ -56,6 +56,20 @@ void InitChannel()
 /************************/
 /**  Convert routines  **/
 /************************/
+// Convert channel 8b with limit and deadband
+uint8_t convert_channel_8b_limit_deadband(uint8_t num,uint8_t min,uint8_t mid, uint8_t max, uint8_t deadband)
+{
+	uint16_t val=limit_channel_100(num);		// 204<->1844
+	uint16_t db_low=CHANNEL_MID-deadband, db_high=CHANNEL_MID+deadband; // 1024+-deadband
+	if(val>=db_low && val<=db_high)
+		return mid;
+	else if(val<db_low)
+		val=min+(val-CHANNEL_MIN_100)*(mid-min)/(db_low-CHANNEL_MIN_100);
+	else
+		val=mid+(val-db_high)*(max-mid)/(CHANNEL_MAX_100-1-db_high);
+	return val;
+}
+
 // Revert a channel and store it
 void reverse_channel(uint8_t num)
 {
@@ -67,7 +81,7 @@ void reverse_channel(uint8_t num)
 uint16_t convert_channel_ppm(uint8_t num)
 {
 	uint16_t val=Channel_data[num];
-	return (((val<<2)+val)>>3)+860;									//value range 860<->2140 -125%<->+125%
+	return (((val<<2)+val)>>3)+860;				//value range 860<->2140 -125%<->+125%
 }
 // Channel value 100% is converted to 10bit values 0<->1023
 uint16_t convert_channel_10b(uint8_t num)

Multiprotocol/GD00X_nrf24l01.ino

@@ -72,18 +72,8 @@ static void __attribute__((unused)) GD00X_send_packet()
 		{
 			packet[0]=convert_channel_16b_limit(THROTTLE,0,100);	// 0..100
 
-			// Deadband is needed on aileron
+			// Deadband is needed on aileron, 40 gives +-6%
-			uint16_t aileron=limit_channel_100(AILERON);			// 204<->1844
+			packet[2]=convert_channel_8b_limit_deadband(AILERON,0x3F,0x20,0x00,40);	// Aileron: 3F..20..00
-			#define GD00X_V2_DB_MIN 1024-40
-			#define GD00X_V2_DB_MAX 1024+40
-			if(aileron>GD00X_V2_DB_MIN && aileron<GD00X_V2_DB_MAX)
-				packet[1]=0x20;	// Send the channel centered
-			else // Ail:  0x3F..0x20..0x00
-				if(aileron>GD00X_V2_DB_MAX)
-					packet[1]=0x1F-((aileron-GD00X_V2_DB_MAX)*(0x20)/(CHANNEL_MAX_100+1-GD00X_V2_DB_MAX));	// 1F..00
-				else
-					packet[1]=0x3F-((aileron-CHANNEL_MIN_100)*(0x1F)/(GD00X_V2_DB_MIN-CHANNEL_MIN_100));	// 3F..21
-
 			// Trims must be in a seperate channel for this model
 			packet[2]=0x3F-(convert_channel_8b(CH5)>>2);			// Trim: 0x3F..0x20..0x00
 

Multiprotocol/KF606_nrf24l01.ino

@@ -38,8 +38,10 @@ static void __attribute__((unused)) KF606_send_packet()
 	{
 		packet[0]= 0x55;
 		packet[1]= convert_channel_8b(THROTTLE);					// 0..255
-		packet[2]= convert_channel_16b_limit(AILERON,0x20,0xE0);	// Low:50..80..AF High:3E..80..C1 
+		// Deadband is needed on aileron, 40 gives +-6%
-		packet[3]= convert_channel_16b_limit(CH5,0xC1,0xDF);		// Trim on a separated channel C1..D0..DF
+		packet[2]=convert_channel_8b_limit_deadband(AILERON,0x20,0x80,0xE0,40);	// Aileron: Max values:20..80..E0, Low rates:50..80..AF, High rates:3E..80..C1
+		// Aileron trim must be on a separated channel C1..D0..DF
+		packet[3]= convert_channel_16b_limit(CH5,0xC1,0xDF);
 	}
 	if(IS_BIND_DONE)
 	{

Multiprotocol/Multiprotocol.h

@@ -19,7 +19,7 @@
 #define VERSION_MAJOR		1
 #define VERSION_MINOR		2
 #define VERSION_REVISION	1
-#define VERSION_PATCH_LEVEL	64
+#define VERSION_PATCH_LEVEL	65
 
 //******************
 // Protocols

Multiprotocol/POTENSIC_nrf24l01.ino

@@ -44,7 +44,8 @@ static void __attribute__((unused)) POTENSIC_send_packet()
 	else
 	{ 
 		packet[0] = 0x64;
-		packet[1] = convert_channel_16b_limit(THROTTLE,0,100)&0xFE;
+		// Deadband is needed on throttle to emulate the spring to neutral otherwise the quad behaves weirdly, 160 gives +-20%
+		packet[1] = convert_channel_8b_limit_deadband(THROTTLE,0x00,0x19,0x32,160)<<1;	// Throttle 00..19..32 *2
 		uint8_t elevator=convert_channel_8b(ELEVATOR)>>3;			
 		packet[2] = ((255-convert_channel_8b(RUDDER))&0xF8)|(elevator>>2);
 		packet[3] = (elevator<<6)|(((255-convert_channel_8b(AILERON))>>2)&0xFE);

Multiprotocol/TX_Def.h

@@ -40,6 +40,8 @@
 #define CHANNEL_MAX_125	2047	//	125%
 #define CHANNEL_MIN_125	0		//	125%
 
+#define CHANNEL_MID		1024
+
 #define CHANNEL_MIN_COMMAND 784		// 1350us
 #define CHANNEL_SWITCH		1104	// 1550us
 #define CHANNEL_MAX_COMMAND 1424	// 1750us