Add Serial1.transmitterEnable(pin) for RS-485

teensy/HardwareSerial.cpp

 	rx_buffer_tail = 0;
 }
 
+void HardwareSerial::transmitterEnable(uint8_t pin)
+{
+	while (transmitting) ;
+	pinMode(pin, OUTPUT);
+	digitalWrite(pin, LOW);
+	tx_enable_pin = pin;
+}
+
 int HardwareSerial::available(void)
 {
 	uint8_t head, tail;

teensy/HardwareSerial.h

 	}
 	void _begin(uint16_t baud_count, uint8_t pin);
 	void end(void);
+	void transmitterEnable(uint8_t pin);
 	virtual int available(void);
 	virtual int peek(void);
 	virtual int read(void);

teensy3/HardwareSerial.h

 void serial_begin(uint32_t divisor);
 void serial_format(uint32_t format);
 void serial_end(void);
+void serial_set_transmit_pin(uint8_t pin);
 void serial_putchar(uint32_t c);
 void serial_write(const void *buf, unsigned int count);
 void serial_flush(void);
 					  serial_begin(BAUD2DIV(baud));
 					  serial_format(format); }
 	virtual void end(void)		{ serial_end(); }
+	virtual void transmitterEnable(uint8_t pin) { serial_set_transmit_pin(pin); }
 	virtual int available(void)     { return serial_available(); }
 	virtual int peek(void)          { return serial_peek(); }
 	virtual int read(void)          { return serial_getchar(); }
 	virtual void flush(void)        { serial_flush(); }
-	virtual void clear(void)                { serial_clear(); }
+	virtual void clear(void)	{ serial_clear(); }
 	virtual size_t write(uint8_t c) { serial_putchar(c); return 1; }
 	size_t write(unsigned long n)   { return write((uint8_t)n); }
 	size_t write(long n)            { return write((uint8_t)n); }
 	virtual int peek(void)          { return serial2_peek(); }
 	virtual int read(void)          { return serial2_getchar(); }
 	virtual void flush(void)        { serial2_flush(); }
-	virtual void clear(void)                { serial2_clear(); }
+	virtual void clear(void)	{ serial2_clear(); }
 	virtual size_t write(uint8_t c) { serial2_putchar(c); return 1; }
 	size_t write(unsigned long n)   { return write((uint8_t)n); }
 	size_t write(long n)            { return write((uint8_t)n); }
 	virtual int peek(void)          { return serial3_peek(); }
 	virtual int read(void)          { return serial3_getchar(); }
 	virtual void flush(void)        { serial3_flush(); }
-	virtual void clear(void)                { serial3_clear(); }
+	virtual void clear(void)	{ serial3_clear(); }
 	virtual size_t write(uint8_t c) { serial3_putchar(c); return 1; }
 	size_t write(unsigned long n)   { return write((uint8_t)n); }
 	size_t write(long n)            { return write((uint8_t)n); }

teensy3/serial1.c

 static volatile BUFTYPE tx_buffer[TX_BUFFER_SIZE];
 static volatile BUFTYPE rx_buffer[RX_BUFFER_SIZE];
 static volatile uint8_t transmitting = 0;
+static volatile uint8_t *transmit_pin=NULL;
 #if TX_BUFFER_SIZE > 255
 static volatile uint16_t tx_buffer_head = 0;
 static volatile uint16_t tx_buffer_tail = 0;
 	rx_buffer_tail = 0;
 }
 
+void serial_set_transmit_pin(uint8_t pin)
+{
+	while (transmitting) ;
+	pinMode(pin, OUTPUT);
+	digitalWrite(pin, LOW);
+	transmit_pin = portOutputRegister(pin);
+}
+
 void serial_putchar(uint32_t c)
 {
-	uint32_t head;
+	uint32_t head, n;
 
 	if (!(SIM_SCGC4 & SIM_SCGC4_UART0)) return;
+	if (transmit_pin) *transmit_pin = 1;
 	head = tx_buffer_head;
 	if (++head >= TX_BUFFER_SIZE) head = 0;
 	while (tx_buffer_tail == head) {
 			if ((UART0_S1 & UART_S1_TDRE)) {
 				uint32_t tail = tx_buffer_tail;
 				if (++tail >= TX_BUFFER_SIZE) tail = 0;
-				UART0_D = tx_buffer[tail];
+				n = tx_buffer[tail];
+				if (use9Bits) UART0_C3 = (UART0_C3 & ~0x40) | ((n & 0x100) >> 2);
+				UART0_D = n;
 				tx_buffer_tail = tail;
 			}
 		} else if (priority >= 256) {
 {
 	const uint8_t *p = (const uint8_t *)buf;
 	const uint8_t *end = p + count;
-        uint32_t head;
+        uint32_t head, n;
 
         if (!(SIM_SCGC4 & SIM_SCGC4_UART0)) return;
+	if (transmit_pin) *transmit_pin = 1;
 	while (p < end) {
         	head = tx_buffer_head;
         	if (++head >= TX_BUFFER_SIZE) head = 0;
 					if ((UART0_S1 & UART_S1_TDRE)) {
 						uint32_t tail = tx_buffer_tail;
 						if (++tail >= TX_BUFFER_SIZE) tail = 0;
-						UART0_D = tx_buffer[tail];
+						n = tx_buffer[tail];
+						if (use9Bits) UART0_C3 = (UART0_C3 & ~0x40) | ((n & 0x100) >> 2);
+						UART0_D = n;
 						tx_buffer_tail = tail;
 					}
 				} else if (priority >= 256) {
 	}
 	if ((c & UART_C2_TCIE) && (UART0_S1 & UART_S1_TC)) {
 		transmitting = 0;
+		if (transmit_pin) *transmit_pin = 0;
 		UART0_C2 = C2_TX_INACTIVE;
 	}
 }