Fix/Add seralEventUSB1 and serialEventUSB2

The code for T3.x was broken, especially for USB2...

And the code was not setup for T4.x.  So added it.

teensy3/core_pins.h

 // Probably should be in a better spot.  
 extern uint8_t yield_active_check_flags;
 
-#define YIELD_CHECK_USB_SERIAL 		0x1   // check the USB for Serial.available()
+#define YIELD_CHECK_USB_SERIAL 		0x1   	// check the USB for Serial.available()
 #define YIELD_CHECK_HARDWARE_SERIAL 0x2		// check Hardware Serial ports available
 #define YIELD_CHECK_EVENT_RESPONDER	0x4		// User has created eventResponders that use yield
+#define YIELD_CHECK_USB_SERIALUSB1  0x8		// Check for SerialUSB1
+#define YIELD_CHECK_USB_SERIALUSB2  0x10	// Check for SerialUSB2
 
 void yield(void);
 

teensy3/serialEventUSB1.cpp

+
+#include <Arduino.h>
+void serialEventUSB1() __attribute__((weak));
+void serialEventUSB1() {}
+uint8_t _serialEventUSB1_default PROGMEM = 1;	

teensy3/serialEventUSB2.cpp

+
+#include <Arduino.h>
+void serialEventUSB2() __attribute__((weak));
+void serialEventUSB2() {}
+uint8_t _serialEventUSB2_default PROGMEM = 1;	

teensy3/usb_inst.cpp

 #endif
 
 #endif // F_CPU
-
-//void serialEvent() __attribute__((weak));
-//void serialEvent() {}
-void serialEventUSB1() __attribute__((weak));
-void serialEventUSB1() {}
-void serialEventUSB2() __attribute__((weak));
-void serialEventUSB2() {}

teensy3/yield.cpp

 
 #ifdef USB_TRIPLE_SERIAL
 uint8_t yield_active_check_flags = YIELD_CHECK_USB_SERIAL | YIELD_CHECK_USB_SERIALUSB1 | YIELD_CHECK_USB_SERIALUSB2; // default to check USB.
+extern const uint8_t _serialEventUSB2_default;	
+extern const uint8_t _serialEventUSB1_default;	
+
 #elif defined(USB_DUAL_SERIAL)
 uint8_t yield_active_check_flags = YIELD_CHECK_USB_SERIAL | YIELD_CHECK_USB_SERIALUSB1; // default to check USB.
+extern const uint8_t _serialEventUSB1_default;	
+
 #else
 uint8_t yield_active_check_flags = YIELD_CHECK_USB_SERIAL; // default to check USB.
 #endif
+
 extern const uint8_t _serialEvent_default;	
 
 void yield(void) __attribute__ ((weak));
 #endif
 #ifdef USB_TRIPLE_SERIAL
 	if (yield_active_check_flags & YIELD_CHECK_USB_SERIALUSB2) {
-		if (SerialUSB1.available()) serialEventUSB1();
+		if (SerialUSB2.available()) serialEventUSB2();
 		if (_serialEventUSB2_default) yield_active_check_flags &= ~YIELD_CHECK_USB_SERIALUSB2;
 	}
 #endif

teensy4/EventResponder.cpp

 // TODO: interrupt disable/enable needed in many places!!!
 // BUGBUG: See if file name order makes difference?
 uint8_t _serialEvent_default __attribute__((weak)) PROGMEM = 0 ;	
+uint8_t _serialEventUSB1_default __attribute__((weak)) PROGMEM = 0 ;	
+uint8_t _serialEventUSB2_default __attribute__((weak)) PROGMEM = 0 ;	
 
 void EventResponder::triggerEventNotImmediate()
 {

teensy4/core_pins.h

 
 // Define a set of flags to know which things yield should check when called. 
 extern uint8_t yield_active_check_flags;
-#define YIELD_CHECK_USB_SERIAL 		0x1   // check the USB for Serial.available()
+
+#define YIELD_CHECK_USB_SERIAL 		0x1   	// check the USB for Serial.available()
 #define YIELD_CHECK_HARDWARE_SERIAL 0x2		// check Hardware Serial ports available
 #define YIELD_CHECK_EVENT_RESPONDER	0x4		// User has created eventResponders that use yield
+#define YIELD_CHECK_USB_SERIALUSB1  0x8		// Check for SerialUSB1
+#define YIELD_CHECK_USB_SERIALUSB2  0x10	// Check for SerialUSB2
+
 void yield(void);
 
 void delay(uint32_t msec);

teensy4/serialEventUSB1.cpp

+
+#include <Arduino.h>
+void serialEventUSB1() __attribute__((weak));
+void serialEventUSB1() {}
+uint8_t _serialEventUSB1_default PROGMEM = 1;	

teensy4/serialEventUSB2.cpp

+
+#include <Arduino.h>
+void serialEventUSB2() __attribute__((weak));
+void serialEventUSB2() {}
+uint8_t _serialEventUSB2_default PROGMEM = 1;	

teensy4/yield.cpp

 #include <Arduino.h>
 #include "EventResponder.h"
 
+#ifdef USB_TRIPLE_SERIAL
+uint8_t yield_active_check_flags = YIELD_CHECK_USB_SERIAL | YIELD_CHECK_USB_SERIALUSB1 | YIELD_CHECK_USB_SERIALUSB2; // default to check USB.
+extern const uint8_t _serialEventUSB2_default;	
+extern const uint8_t _serialEventUSB1_default;	
+
+#elif defined(USB_DUAL_SERIAL)
+uint8_t yield_active_check_flags = YIELD_CHECK_USB_SERIAL | YIELD_CHECK_USB_SERIALUSB1; // default to check USB.
+extern const uint8_t _serialEventUSB1_default;	
+
+#else
 uint8_t yield_active_check_flags = YIELD_CHECK_USB_SERIAL; // default to check USB.
+#endif
+
 extern const uint8_t _serialEvent_default;	
 
 void yield(void) __attribute__ ((weak));
 		if (_serialEvent_default) yield_active_check_flags &= ~YIELD_CHECK_USB_SERIAL;
 	}
 
+#if defined(USB_DUAL_SERIAL) || defined(USB_TRIPLE_SERIAL)
+	if (yield_active_check_flags & YIELD_CHECK_USB_SERIALUSB1) {
+		if (SerialUSB1.available()) serialEventUSB1();
+		if (_serialEventUSB1_default) yield_active_check_flags &= ~YIELD_CHECK_USB_SERIALUSB1;
+	}
+#endif
+#ifdef USB_TRIPLE_SERIAL
+	if (yield_active_check_flags & YIELD_CHECK_USB_SERIALUSB2) {
+		if (SerialUSB2.available()) serialEventUSB2();
+		if (_serialEventUSB2_default) yield_active_check_flags &= ~YIELD_CHECK_USB_SERIALUSB2;
+	}
+#endif
+
 	// Current workaround until integrate with EventResponder.
 	if (yield_active_check_flags & YIELD_CHECK_HARDWARE_SERIAL) HardwareSerial::processSerialEventsList();