Add serialEvent (USB) and serialEvent1-3 (serial)

teensy3/HardwareSerial.h

 	virtual size_t write9bit(uint32_t c)	{ serial_putchar(c); return 1; }
 };
 extern HardwareSerial Serial1;
+extern void serialEvent1(void);
 
 class HardwareSerial2 : public HardwareSerial
 {
 	virtual size_t write9bit(uint32_t c)	{ serial2_putchar(c); return 1; }
 };
 extern HardwareSerial2 Serial2;
+extern void serialEvent2(void);
 
 class HardwareSerial3 : public HardwareSerial
 {
 	virtual size_t write9bit(uint32_t c)	{ serial3_putchar(c); return 1; }
 };
 extern HardwareSerial3 Serial3;
+extern void serialEvent3(void);
 
 #endif
 #endif

teensy3/HardwareSerial1.cpp

 
 HardwareSerial Serial1;
 
+void serialEvent1() __attribute__((weak));
+void serialEvent1() {}

teensy3/HardwareSerial2.cpp

 
 HardwareSerial2 Serial2;
 
+void serialEvent2() __attribute__((weak));
+void serialEvent2() {}

teensy3/HardwareSerial3.cpp

 
 HardwareSerial3 Serial3;
 
+void serialEvent3() __attribute__((weak));
+void serialEvent3() {}

teensy3/usb_inst.cpp

 #endif
 
 #endif // F_CPU
+
+void serialEvent() __attribute__((weak));
+void serialEvent() {}

teensy3/usb_seremu.h

         operator bool() { return usb_configuration; }
 };
 extern usb_seremu_class Serial;
+extern void serialEvent(void);
 #endif // __cplusplus
 
 
 };
 
 extern usb_seremu_class Serial;
+extern void serialEvent(void);
 #endif // __cplusplus
 
 

teensy3/usb_serial.h

 
 };
 extern usb_serial_class Serial;
+extern void serialEvent(void);
 #endif // __cplusplus
 
 
 };
 
 extern usb_serial_class Serial;
+extern void serialEvent(void);
 #endif // __cplusplus
 
 #endif // F_CPU

teensy3/yield.c → teensy3/yield.cpp

 /* Teensyduino Core Library
  * http://www.pjrc.com/teensy/
- * Copyright (c) 2013 PJRC.COM, LLC.
+ * Copyright (c) 2014 PJRC.COM, LLC.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
  * SOFTWARE.
  */
 
+#include "core_pins.h"
+#include "HardwareSerial.h"
+#include "usb_serial.h"
+#include "usb_seremu.h"
+
 void yield(void) __attribute__ ((weak));
-void yield(void) {};
+void yield(void)
+{
+	static uint8_t running=0;
+
+	if (running) return; // TODO: does this need to be atomic?
+	running = 1;
+	if (Serial.available()) serialEvent();
+	if (Serial1.available()) serialEvent1();
+	if (Serial2.available()) serialEvent2();
+	if (Serial3.available()) serialEvent3();
+	running = 0;
+};