Removed SBUS trainer option

Lua_scripts/MultiChan.txt

@@ -6,6 +6,7 @@
 14,4,Bayang,DHD_D4,1,Flip,RTH,Pict,Video,HLess,Invert,Rates,TakeOf,EmStop
 14,5,Bayang,QX100,1,Flip,RTH,Pict,Video,HLess,Invert,Rates,TakeOf,EmStop
 59,0,BayangRX,RX,1,AnAux1,AnAux2,Flip,RTH,Pict,Video
+59,1,BayangRX,CPPM,1,AnAux1,AnAux2,Flip,RTH,Pict,Video
 41,0,Bugs,3-6-8,0,Arm,Angle,Flip,Pict,Video,LED
 42,0,BugsMini,Mini,0,Arm,Angle,Flip,Pict,Video,LED
 42,1,BugsMini,3H,0,Arm,Angle,Flip,Pict,Video,LED,AltHol
@@ -34,6 +35,7 @@
 6,3,DSM,X_11,0,CH5,CH6,CH7,CH8,CH9,CH10,CH11,CH12,n-a,ThKill
 6,4,DSM,AUTO,0,CH5,CH6,CH7,CH8,CH9,CH10,CH11,CH12,n-a,ThKill
 70,0,DSM_RX,RX,0,CH5,CH6,CH7,CH8,CH9,CH10,CH11,CH12
+70,1,DSM_RX,CPPM,0,CH5,CH6,CH7,CH8,CH9,CH10,CH11,CH12
 45,0,E01X,E012,1,n-a,Flip,n-a,HLess,RTH
 45,1,E01X,E015,1,Arm,Flip,LED,HLess,RTH
 45,2,E01X,E016H,1,Stop,Flip,n-a,HLess,RTH
@@ -54,6 +56,7 @@
 28,4,Flysky_AFHDS2A,PWM_IB16,0,CH5,CH6,CH7,CH8,CH9,CH10,CH11,CH12,CH13,CH14,CH15,CH16
 28,5,Flysky_AFHDS2A,PPM_IB16,0,CH5,CH6,CH7,CH8,CH9,CH10,CH11,CH12,CH13,CH14,CH15,CH16
 56,0,Flysky2A_RX,RX,0,CH5,CH6,CH7,CH8,CH9,CH10,CH11,CH12,CH13,CH14
+56,1,Flysky2A_RX,CPPM,0,CH5,CH6,CH7,CH8,CH9,CH10,CH11,CH12,CH13,CH14
 53,0,Height,5ch,0,Gear
 53,1,Height,8ch,0,Gear,Gyro,Flap,Light
 25,0,FrSkyV,V8,0,CH5,CH6,CH7,CH8
@@ -80,6 +83,7 @@
 55,0,FrSkyRX,RX,0,CH5,CH6,CH7,CH8,CH9,CH10,CH11,CH12,CH13,CH14,CH15,CH16
 55,1,FrSkyRX,CloneTX,0
 55,2,FrSkyRX,EraseTX,0
+55,3,FrSkyRX,CPPM,0,CH5,CH6,CH7,CH8,CH9,CH10,CH11,CH12,CH13,CH14,CH15,CH16
 58,0,FX816,P38,1
 20,0,FY326,FY326,1,Flip,RTH,HLess,Expert,Calib
 20,1,FY326,FY319,1,Flip,RTH,HLess,Expert,Calib

Multiprotocol/AFHDS2A_Rx_a7105.ino

@@ -189,9 +189,9 @@ uint16_t AFHDS2A_RX_callback()
 					RX_RSSI = map16b(rssi, 160, 8, 0, 128);
 					AFHDS2A_RX_build_telemetry_packet();
 					telemetry_link = 1;
-					#if defined (SEND_SBUS_SERIAL) || defined (SEND_CPPM)
+					#ifdef SEND_CPPM
 						if(sub_protocol>0)
-							telemetry_link = 0x80 + sub_protocol;	// Disable telemetry output, type SBUS=1, type CPPM=2
+							telemetry_link |= 0x80;	// Disable telemetry output
 					#endif
 				}
 				rx_data_started = true;

Multiprotocol/Bayang_Rx_nrf24l01.ino

@@ -151,9 +151,9 @@ uint16_t BAYANG_RX_callback()
 				if ((telemetry_link & 0x7F) == 0) {
 					Bayang_Rx_build_telemetry_packet();
 					telemetry_link = 1;
-					#if defined (SEND_SBUS_SERIAL) || defined (SEND_CPPM)
+					#ifdef SEND_CPPM
 						if(sub_protocol>0)
-							telemetry_link = 0x80 + sub_protocol;	// Disable telemetry output, type SBUS=1, type CPPM=2
+							telemetry_link |= 0x80;	// Disable telemetry output
 					#endif
 				}
 				rx_data_started = true;

Multiprotocol/DSM_Rx_cyrf6936.ino

@@ -155,9 +155,9 @@ static void __attribute__((unused)) DSM_RX_build_telemetry_packet()
 		packet_in[idx++] = bits & 0xff;
 	// Send telemetry
 	telemetry_link = 1;
-	#if defined (SEND_SBUS_SERIAL) || defined (SEND_CPPM)
+	#ifdef SEND_CPPM
 		if(sub_protocol>0)
-			telemetry_link = 0x80 + sub_protocol;	// Disable telemetry output, type SBUS=1, type CPPM=2
+			telemetry_link |= 0x80;	// Disable telemetry output
 	#endif
 }
 

Multiprotocol/FrSky_Rx_cc2500.ino

@@ -528,7 +528,7 @@ uint16_t FRSKY_RX_callback()
 						eeprom_write_byte((EE_ADDR)temp++, rx_tx_addr[3]);
 						eeprom_write_byte((EE_ADDR)temp++, rx_tx_addr[2]);
 						eeprom_write_byte((EE_ADDR)temp++, rx_tx_addr[1]);
-						if(sub_protocol == FRSKY_RX || sub_protocol >= FRSKY_SBUS)	// FRSKY_RX, FRSKY_SBUS, FRSKY_CPPM
+						if(sub_protocol == FRSKY_RX || sub_protocol == FRSKY_CPPM)	// FRSKY_RX, FRSKY_CPPM
 							eeprom_write_byte((EE_ADDR)temp++, FRSKY_RX_finetune);
 						if(FRSKY_RX_format != FRSKY_RX_D16v2FCC && FRSKY_RX_format != FRSKY_RX_D16v2LBT)
 							for (ch = 0; ch < 47; ch++)
@@ -579,9 +579,9 @@ uint16_t FRSKY_RX_callback()
 						{ // send channels to TX
 							FRSKY_RX_build_telemetry_packet();
 							telemetry_link = 1;
-							#if defined (SEND_SBUS_SERIAL) || defined (SEND_CPPM)
+							#ifdef SEND_CPPM
-								if(sub_protocol >= FRSKY_SBUS)
+								if(sub_protocol == FRSKY_CPPM)
-									telemetry_link = 0x81 + sub_protocol - FRSKY_SBUS;	// Disable telemetry output, type SBUS=1, type CPPM=2
+									telemetry_link |= 0x80;		// Disable telemetry output
 							#endif
 						}
 						pps_counter++;

Multiprotocol/Multi.txt

@@ -52,11 +52,11 @@
 52,ZSX,280
 53,Height,5ch,8ch
 54,Scanner
-55,Frsky_RX,Multi,CloneTX,EraseTX,SBUS,CPPM
+55,Frsky_RX,Multi,CloneTX,EraseTX,CPPM
-56,AFHDS2A_RX,Multi,SBUS,CPPM
+56,AFHDS2A_RX,Multi,CPPM
 57,HoTT,Sync,No_Sync
 58,FX816,P38
-59,Bayang_RX,Multi,SBUS,CPPM
+59,Bayang_RX,Multi,CPPM
 60,Pelikan,Pro,Lite
 61,Tiger
 62,XK,X450,X420
@@ -67,7 +67,7 @@
 67,LR12,LR12,LR12_6ch
 68,Skyartec
 69,ESKYv2,150V2
-70,DSM_RX,Multi,SBUS,CPPM
+70,DSM_RX,Multi,CPPM
 71,JJRC345,JJRC345,SkyTmblr
 72,Q90C
 73,Kyosho,FHSS,Hype

Multiprotocol/Multi_Protos.ino

@@ -156,16 +156,16 @@ const char STR_SUBTYPE_JJRC345[] =    "\x08""JJRC345\0""SkyTmblr";
 
 #define NO_SUBTYPE		nullptr
 
-#if defined (SEND_SBUS_SERIAL) || defined (SEND_CPPM)
+#ifdef SEND_CPPM
-	const char STR_SUBTYPE_FRSKY_RX[] =   "\x07""Multi\0 ""CloneTX""EraseTX""SBUS\0  ""CPPM\0  ";
+	const char STR_SUB_FRSKY_RX[] =   "\x07""Multi\0 ""CloneTX""EraseTX""CPPM\0  ";
-	#define FRSBUSCPPM 5
+	#define FRCPPM   4
-	const char STR_SBUS_CPPM[] =           "\x05""Multi""SBUS\0""CPPM\0";
+	const char STR_CPPM[] =           "\x05""Multi""CPPM\0";
-	#define SBUS_CPPM 3
+	#define NBR_CPPM 2
 #else
-	const char STR_SUBTYPE_FRSKY_RX[] =   "\x07""Multi\0 ""CloneTX""EraseTX";
+	const char STR_SUB_FRSKY_RX[] =   "\x07""Multi\0 ""CloneTX""EraseTX";
-	#define FRSBUSCPPM 3
+	#define FRCPPM   3
-	#define STR_SBUS_CPPM NO_SUBTYPE
+	#define STR_CPPM NO_SUBTYPE
-	#define SBUS_CPPM 0
+	#define NBR_CPPM 0
 #endif
 
 enum
@@ -195,7 +195,7 @@ const mm_protocol_definition multi_protocols[] = {
 		{PROTO_BAYANG,     STR_BAYANG,    STR_SUBTYPE_BAYANG,    6, OPTION_TELEM,   0, 0, SW_NRF,    BAYANG_init,     BAYANG_callback     },
 	#endif
 	#if defined(BAYANG_RX_NRF24L01_INO)
-		{PROTO_BAYANG_RX,  STR_BAYANG_RX, STR_SBUS_CPPM, SBUS_CPPM, OPTION_NONE,    0, 0, SW_NRF,    BAYANG_RX_init,  BAYANG_RX_callback  },	
+		{PROTO_BAYANG_RX,  STR_BAYANG_RX, STR_CPPM,       NBR_CPPM, OPTION_NONE,    0, 0, SW_NRF,    BAYANG_RX_init,  BAYANG_RX_callback  },	
 	#endif
 	#if defined(BUGS_A7105_INO)
 		{PROTO_BUGS,       STR_BUGS,      NO_SUBTYPE,            0, OPTION_NONE,    0, 0, SW_A7105,  BUGS_init,       BUGS_callback       },
@@ -228,7 +228,7 @@ const mm_protocol_definition multi_protocols[] = {
 		{PROTO_DSM,        STR_DSM,       STR_SUBTYPE_DSM,       5, OPTION_MAXTHR,  0, 1, SW_CYRF,   DSM_init,        DSM_callback        },
 	#endif
 	#if defined(DSM_RX_CYRF6936_INO)
-		{PROTO_DSM_RX,     STR_DSM_RX,    STR_SBUS_CPPM, SBUS_CPPM, OPTION_NONE,    0, 1, SW_CYRF,   DSM_RX_init,     DSM_RX_callback     },
+		{PROTO_DSM_RX,     STR_DSM_RX,    STR_CPPM,       NBR_CPPM, OPTION_NONE,    0, 1, SW_CYRF,   DSM_RX_init,     DSM_RX_callback     },
 	#endif
 	#if defined(E010R5_CYRF6936_INO)
 		{PROTO_E010R5,     STR_E010R5,    NO_SUBTYPE,            0, OPTION_NONE,    0, 0, SW_CYRF,   E010R5_init,     E010R5_callback     },
@@ -258,14 +258,14 @@ const mm_protocol_definition multi_protocols[] = {
 		{PROTO_AFHDS2A,    STR_AFHDS2A,   STR_SUBTYPE_AFHDS2A,   8, OPTION_SRVFREQ, 1, 1, SW_A7105,  AFHDS2A_init,    AFHDS2A_callback    },
 	#endif
 	#if defined(AFHDS2A_RX_A7105_INO)
-		{PROTO_AFHDS2A_RX, STR_AFHDS2A_RX,STR_SBUS_CPPM, SBUS_CPPM, OPTION_NONE,    0, 0, SW_A7105,  AFHDS2A_RX_init, AFHDS2A_RX_callback },
+		{PROTO_AFHDS2A_RX, STR_AFHDS2A_RX,STR_CPPM,       NBR_CPPM, OPTION_NONE,    0, 0, SW_A7105,  AFHDS2A_RX_init, AFHDS2A_RX_callback },
 	#endif
 	#if defined(FQ777_NRF24L01_INO)
 		{PROTO_FQ777,      STR_FQ777,     NO_SUBTYPE,            0, OPTION_NONE,    0, 0, SW_NRF,    FQ777_init,      FQ777_callback      },
 	#endif
 //OpenTX 2.3.x issue: DO NOT CHANGE ORDER below
 	#if defined(FRSKY_RX_CC2500_INO)
-		{PROTO_FRSKY_RX,   STR_FRSKY_RX,  STR_SUBTYPE_FRSKY_RX, FRSBUSCPPM, OPTION_RFTUNE,  0, 0, SW_CC2500, FRSKY_RX_init,   FRSKY_RX_callback   },
+		{PROTO_FRSKY_RX,   STR_FRSKY_RX,  STR_SUB_FRSKY_RX, FRCPPM, OPTION_RFTUNE,  0, 0, SW_CC2500, FRSKY_RX_init,   FRSKY_RX_callback   },
 	#endif
 	#if defined(FRSKYD_CC2500_INO)
 		{PROTO_FRSKYD,     STR_FRSKYD,    STR_SUBTYPE_FRSKYD,    2, OPTION_RFTUNE,  0, 0, SW_CC2500, FRSKYD_init,     FRSKYD_callback     },

Multiprotocol/Multiprotocol.h

@@ -19,7 +19,7 @@
 #define VERSION_MAJOR		1
 #define VERSION_MINOR		3
 #define VERSION_REVISION	2
-#define VERSION_PATCH_LEVEL	57
+#define VERSION_PATCH_LEVEL	58
 
 #define MODE_SERIAL 0
 
@@ -378,8 +378,7 @@ enum FRSKY_RX
 	FRSKY_RX	= 0,
 	FRSKY_CLONE	= 1,
 	FRSKY_ERASE	= 2,
-	FRSKY_SBUS  = 3,
+	FRSKY_CPPM  = 3,
-	FRSKY_CPPM  = 4,
 };
 
 enum FRSKYL

Multiprotocol/Multiprotocol.ino

@@ -834,24 +834,17 @@ bool Update_All()
 	#endif //ENABLE_PPM
 	update_led_status();
 	
-	#if defined(SEND_SBUS_SERIAL) || defined(SEND_CPPM)
+	#ifdef SEND_CPPM
 		if ( telemetry_link & 0x80 )
 		{ // Protocol requests telemetry to be disabled
 			if( protocol == PROTO_FRSKY_RX || protocol == PROTO_AFHDS2A_RX || protocol == PROTO_BAYANG_RX || protocol == PROTO_DSM_RX )
 			{ // RX protocol
 				if(RX_LQI == 0)
-					telemetry_link = 0x00;						// restore normal telemetry on connection loss
+					telemetry_link = 0x00;					// restore normal telemetry on connection loss
-				else
+				else if(telemetry_link & 1)
-				{
+				{ // New data available
-					#ifdef SEND_SBUS_SERIAL
+					Send_CCPM_USART1();
-						if(telemetry_link & 1)
+					telemetry_link &= 0xFE;					// update done
-							Send_SBUS_USART1();
-					#endif
-					#ifdef SEND_CPPM
-						if(telemetry_link & 2)
-							Send_CCPM_USART1();
-					#endif
-					telemetry_link = 0x80;						// update done
 				}
 			}
 		}
@@ -1169,6 +1162,11 @@ static void protocol_init()
 		#endif
 		binding_idx=0;
 		
+		//Stop CPPM if it was previously running
+		#ifdef SEND_CPPM
+			release_trainer_ppm();
+		#endif
+		
 		//Set global ID and rx_tx_addr
 		MProtocol_id = RX_num + MProtocol_id_master;
 		set_rx_tx_addr(MProtocol_id);
@@ -2113,95 +2111,13 @@ static void __attribute__((unused)) crc8_update(uint8_t byte)
 
 /**************************/
 /**************************/
-/**  SBUS/CPPM routines  **/
+/**    CPPM  routines    **/
 /**************************/
 /**************************/
-#if defined (SEND_SBUS_SERIAL) || defined (SEND_CPPM)
-	uint32_t TrainerTimer ;
-#endif
-
-#ifdef SEND_CPPM
-	bool CppmInitialised = false;
-#endif
-
-#ifdef SEND_SBUS_SERIAL
-	uint8_t SbusFrame[26] ;
-	uint16_t SbusChannels[16] ;
-	bool SbusInitialised = false;
-
-	void Init_SBUS_USART1()
-	{
-		RCC_BASE->APB2ENR |= RCC_APB2ENR_USART1EN ;					// Enable USART1
-		for ( uint8_t i = 0 ; i < NUM_CHN ; i += 1 )
-			SbusChannels[i] = 0x03E0 ;	// Centre position
-		usart_init(USART1);
-		usart_config_gpios_async(USART1,GPIOA,PIN_MAP[PA10].gpio_bit,GPIOA,PIN_MAP[PA9].gpio_bit,SERIAL_8E2);
-		usart_set_baud_rate(USART1, STM32_PCLK2, 100000);
-		USART1_BASE->CR1 |= USART_CR1_PCE_BIT;
-		usart_enable(USART1);
-		SbusInitialised = true;
-		#ifdef SEND_CPPM
-			if(CppmInitialised)
-			{
-				TIMER1_BASE->CR1 = 0 ;
-				CppmInitialised = false;
-			}
-		#endif
-	}
-
-	void Send_SBUS_USART1()
-	{
-		if(SbusInitialised ==  false)
-			Init_SBUS_USART1();
-		TrainerTimer = millis() ;
-		len = packet_in[3] ;
-		// pad unused channels to 0x03E0 ;
-		// Scale used channels to centre of 0x03E0
-		uint32_t bitsavailable = 0 ;
-		uint32_t bits = 0 ; ;
-		uint32_t i ;
-		uint32_t value ;
-		uint8_t *packet ;
-		packet = &packet_in[4] ;
-		i = packet_in[2] ;	// Start channel
-		// Load changed channels
-		while ( len )
-		{
-			while ( bitsavailable < 11 )
-			{
-				bits |= *packet++ << bitsavailable ;
-				bitsavailable += 8 ;
-			}
-			value = bits & 0x07FF ;
-			value -= (0x0400 - 0x03E0) ;
-			SbusChannels[i++] = value ;
-			bitsavailable -= 11 ;
-			bits >>= 11 ;
-			len-- ;
-		}
-		bitsavailable = 0 ;
-		bits = 0 ;
-		packet = SbusFrame ;
-		*packet++ = 0x0F ;
-		for ( i = 0 ; i < 16 ; i += 1 )
-		{
-			bits |= SbusChannels[i] << bitsavailable ;
-			bitsavailable += 11 ;
-			while ( bitsavailable >= 8 )
-			{
-				*packet++ = bits ;
-				bits >>= 8 ;
-				bitsavailable -= 8 ;
-			}
-		}
-		*packet++ = 0 ;
-		*packet = 0 ;
-		usart_tx( USART1, SbusFrame, 25 ) ;
-	}
-#endif
-
 #ifdef SEND_CPPM
 	#define PPM_CENTER 1500*2
+	uint32_t TrainerTimer ;
+	bool CppmInitialised = false;
 	uint16_t *TrainerPulsePtr ;
 	uint16_t TrainerPpmStream[10] ;
 	int16_t CppmChannels[8] ;
@@ -2241,13 +2157,6 @@ static void __attribute__((unused)) crc8_update(uint8_t byte)
 		RCC_BASE->APB2ENR |= RCC_APB2ENR_TIM1EN ;						// Enable clock
 		setupTrainerPulses() ;
 		RCC_BASE->APB2ENR |= RCC_APB2ENR_IOPAEN ;						// Enable portA clock
-		#ifdef SEND_SBUS_SERIAL
-			if(SbusInitialised)
-			{
-				SbusInitialised = false ;
-				USART1_BASE->CR1 = 0 ;
-			}
-		#endif
 		RCC_BASE->APB2ENR &= ~RCC_APB2ENR_USART1EN ;					// Disable USART1
 
 		GPIOA_BASE->CRH &= ~0x00F0 ;
@@ -2261,19 +2170,27 @@ static void __attribute__((unused)) crc8_update(uint8_t byte)
 		TIMER1_BASE->CCMR1 = 0x6000 ;									// PWM mode 1 (header file has incorrect bits)
 		TIMER1_BASE->EGR = 1 ;
 		TIMER1_BASE->CCER = TIMER_CCER_CC2E ;
-		//	TIMER1_BASE->DIER |= TIMER_DIER_CC2IE ;
 		TIMER1_BASE->DIER |= TIMER_DIER_UIE ;
 		TIMER1_BASE->CR1 = TIMER_CR1_CEN ;
 		nvic_irq_set_priority(NVIC_TIMER1_CC, 4 ) ;
 		nvic_irq_set_priority(NVIC_TIMER1_UP, 4 ) ;
 		HWTimer1.attachInterrupt(TIMER_UPDATE_INTERRUPT,tim1_up);		// Assign function to Timer1/Comp2 interrupt
 		HWTimer1.attachInterrupt(TIMER_CH1,tim1_cc);					// Assign function to Timer1/Comp2 interrupt
-		//	HWTimer1.attachInterrupt(TIMER_CH2,tim1_cc);				// Assign function to Timer1/Comp2 interrupt
 
 		CppmInitialised = true ;
 		HWTimer1.resume() ;
 	}
 
+	void release_trainer_ppm()
+	{
+		if ( CppmInitialised )
+		{
+			TIMER1_BASE->CR1 = 0 ;
+			pinMode(PA9,INPUT) ;
+			CppmInitialised = false ;
+		}
+	}
+
 	void tim1_up()
 	{
 		#define TIMER1_SR_MASK	0x1FFF
@@ -2294,12 +2211,6 @@ static void __attribute__((unused)) crc8_update(uint8_t byte)
 
 	void tim1_cc()
 	{
-		//	if ( ( TIMER1_BASE->DIER & TIMER_DIER_CC2IE ) && ( TIMER1_BASE->SR & TIMER_SR_CC2IF ) )
-		//	{
-		//		GPIOA_BASE->BSRR = 0x0200  ;
-		//  	TIMER1_BASE->SR = 0x1FFF & ~TIMER_SR_CC2IF ;			// Clear flag
-		//	}
-
 		if ( ( TIMER1_BASE->DIER & TIMER_DIER_CC1IE ) && ( TIMER1_BASE->SR & TIMER_SR_CC1IF ) )
 		{
 			// compare interrupt

Multiprotocol/Validate.h

@@ -529,14 +529,12 @@
 #endif
 
 #if defined (STM32_BOARD) && defined (DEBUG_SERIAL)
-	#undef SEND_SBUS_SERIAL
 	#undef SEND_CPPM 
 	#ifdef NRF24L01_INSTALLED
 		#define XN297DUMP_NRF24L01_INO
 	#endif
 #endif
 #if not defined (STM32_BOARD) || not defined (TELEMETRY) || (not defined (FRSKY_RX_TELEMETRY) && not defined (AFHDS2A_RX_TELEMETRY) && not defined (BAYANG_RX_TELEMETRY) && not defined (DSM_RX_CYRF6936_INO))
-	#undef SEND_SBUS_SERIAL
 	#undef SEND_CPPM 
 #endif
 

Multiprotocol/_Config.h

@@ -347,12 +347,9 @@
 /**************************/
 // By default Multi uses the telemetry line to send the received channels using a RX protocol (FrSky, DSM, AFHDS2A, Bayang) to the radio.
 // But this does not work on FrSky radios since the telemetry lines of the internal and external modules are shared (hardware limitation).
-// Using one of the method below (both can be enabled) on a STM32 module enables to go around that issue but needs a hardware modification on the module itself.
+// On a STM32 module and with a simple hardware modification, you can go around this limitation using CPPM to send the trainer information to the radio.
-
+// Hardware modification: add a 1K resistor between the STM32 USART1 TX pin (Boot0 programming TX pin) and the radio bay pin 2.
-//SBUS signal needs an inverter between the STM32 USART1 TX pin and the radio bay pin 2
+//Uncomment to enable
-//#define SEND_SBUS_SERIAL
-
-//CPPM signal needs a resistor between the STM32 USART1 TX pin and the radio bay pin 2
 //#define SEND_CPPM
 
 /****************************/