Fix Hardware Serial transmitterEnable() on Teensy-LC

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 defined(KINETISK)
+  static volatile uint8_t *transmit_pin=NULL;
+  #define transmit_assert()   *transmit_pin = 1
+  #define transmit_deassert() *transmit_pin = 0
+#elif defined(KINETISL)
+  static volatile uint8_t *transmit_pin=NULL;
+  static uint8_t transmit_mask=0;
+  #define transmit_assert()   *(transmit_pin+4) = transmit_mask;
+  #define transmit_deassert() *(transmit_pin+8) = transmit_mask;
+#endif
 #if TX_BUFFER_SIZE > 255
 static volatile uint16_t tx_buffer_head = 0;
 static volatile uint16_t tx_buffer_tail = 0;
 	pinMode(pin, OUTPUT);
 	digitalWrite(pin, LOW);
 	transmit_pin = portOutputRegister(pin);
+	#if defined(KINETISL)
+	transmit_mask = digitalPinToBitMask(pin);
+	#endif
 }
 
 void serial_putchar(uint32_t c)
 	uint32_t head, n;
 
 	if (!(SIM_SCGC4 & SIM_SCGC4_UART0)) return;
-	if (transmit_pin) *transmit_pin = 1;
+	if (transmit_pin) transmit_assert();
 	head = tx_buffer_head;
 	if (++head >= TX_BUFFER_SIZE) head = 0;
 	while (tx_buffer_tail == head) {
         uint32_t head, n;
 
         if (!(SIM_SCGC4 & SIM_SCGC4_UART0)) return;
-	if (transmit_pin) *transmit_pin = 1;
+	if (transmit_pin) transmit_assert();
 	while (p < end) {
         	head = tx_buffer_head;
         	if (++head >= TX_BUFFER_SIZE) head = 0;
 #endif
 	if ((c & UART_C2_TCIE) && (UART0_S1 & UART_S1_TC)) {
 		transmitting = 0;
-		if (transmit_pin) *transmit_pin = 0;
+		if (transmit_pin) transmit_deassert();
 		UART0_C2 = C2_TX_INACTIVE;
 	}
 }

teensy3/serial2.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 defined(KINETISK)
+  static volatile uint8_t *transmit_pin=NULL;
+  #define transmit_assert()   *transmit_pin = 1
+  #define transmit_deassert() *transmit_pin = 0
+#elif defined(KINETISL)
+  static volatile uint8_t *transmit_pin=NULL;
+  static uint8_t transmit_mask=0;
+  #define transmit_assert()   *(transmit_pin+4) = transmit_mask;
+  #define transmit_deassert() *(transmit_pin+8) = transmit_mask;
+#endif
 #if TX_BUFFER_SIZE > 255
 static volatile uint16_t tx_buffer_head = 0;
 static volatile uint16_t tx_buffer_tail = 0;
 	pinMode(pin, OUTPUT);
 	digitalWrite(pin, LOW);
 	transmit_pin = portOutputRegister(pin);
+	#if defined(KINETISL)
+	transmit_mask = digitalPinToBitMask(pin);
+	#endif
 }
 
 void serial2_putchar(uint32_t c)
 	uint32_t head, n;
 
 	if (!(SIM_SCGC4 & SIM_SCGC4_UART1)) return;
-	if (transmit_pin) *transmit_pin = 1;
+	if (transmit_pin) transmit_assert();
 	head = tx_buffer_head;
 	if (++head >= TX_BUFFER_SIZE) head = 0;
 	while (tx_buffer_tail == head) {
         uint32_t head, n;
 
 	if (!(SIM_SCGC4 & SIM_SCGC4_UART1)) return;
-	if (transmit_pin) *transmit_pin = 1;
+	if (transmit_pin) transmit_assert();
 	while (p < end) {
 		head = tx_buffer_head;
 		if (++head >= TX_BUFFER_SIZE) head = 0;
 #endif
 	if ((c & UART_C2_TCIE) && (UART1_S1 & UART_S1_TC)) {
 		transmitting = 0;
-		if (transmit_pin) *transmit_pin = 0;
+		if (transmit_pin) transmit_deassert();
 		UART1_C2 = C2_TX_INACTIVE;
 	}
 }

teensy3/serial3.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 defined(KINETISK)
+  static volatile uint8_t *transmit_pin=NULL;
+  #define transmit_assert()   *transmit_pin = 1
+  #define transmit_deassert() *transmit_pin = 0
+#elif defined(KINETISL)
+  static volatile uint8_t *transmit_pin=NULL;
+  static uint8_t transmit_mask=0;
+  #define transmit_assert()   *(transmit_pin+4) = transmit_mask;
+  #define transmit_deassert() *(transmit_pin+8) = transmit_mask;
+#endif
 #if TX_BUFFER_SIZE > 255
 static volatile uint16_t tx_buffer_head = 0;
 static volatile uint16_t tx_buffer_tail = 0;
 	pinMode(pin, OUTPUT);
 	digitalWrite(pin, LOW);
 	transmit_pin = portOutputRegister(pin);
+	#if defined(KINETISL)
+	transmit_mask = digitalPinToBitMask(pin);
+	#endif
 }
 
 void serial3_putchar(uint32_t c)
 	uint32_t head, n;
 
 	if (!(SIM_SCGC4 & SIM_SCGC4_UART2)) return;
-	if (transmit_pin) *transmit_pin = 1;
+	if (transmit_pin) transmit_assert();
 	head = tx_buffer_head;
 	if (++head >= TX_BUFFER_SIZE) head = 0;
 	while (tx_buffer_tail == head) {
 	}
 	if ((c & UART_C2_TCIE) && (UART2_S1 & UART_S1_TC)) {
 		transmitting = 0;
-		if (transmit_pin) *transmit_pin = 0;
+		if (transmit_pin) transmit_deassert();
 		UART2_C2 = C2_TX_INACTIVE;
 	}
 }