Add serial pin warnings.

blockly/generators/arduino/boards.js

@@ -59,7 +59,7 @@ Blockly.Arduino.Boards.profiles.uno = {
   pwmPins: [['3', '3'], ['5', '5'], ['6', '6'], ['9', '9'], ['10', '10'],
             ['11', '11']],
   serial: [['serial', 'Serial']],
-  serialPins: { serial: [['RX', '0'], ['TX', '1']] },
+  serialPins: { Serial: [['RX', '0'], ['TX', '1']] },
   serialSpeed: [['300', '300'], ['600', '600'], ['1200', '1200'],
                 ['2400', '2400'], ['4800', '4800'], ['9600', '9600'],
                 ['14400', '14400'], ['19200', '19200'], ['28800', '28800'],
@@ -121,10 +121,10 @@ Blockly.Arduino.Boards.profiles.mega = {
   serial: [['serial', 'Serial'], ['serial_1', 'Serial1'],
            ['serial_2', 'Serial2'], ['serial_3', 'Serial3']],
   serialPins: {
-    serial: [['TX', '0'], ['RX', '1']],
-    serial1: [['TX', '18'], ['TX', '19']],
-    serial2: [['TX', '16'], ['TX', '17']],
-    serial3: [['TX', '14'], ['TX', '15']]
+    Serial: [['TX', '0'], ['RX', '1']],
+    Serial1: [['TX', '18'], ['TX', '19']],
+    Serial2: [['TX', '16'], ['TX', '17']],
+    Serial3: [['TX', '14'], ['TX', '15']]
   },
   serialSpeed: Blockly.Arduino.Boards.profiles.uno.serialSpeed,
   spi: [['SPI', 'SPI']],

blockly/generators/arduino/serial.js

@@ -29,6 +29,12 @@ Blockly.Arduino['serial_print'] = function(block) {
       block, 'CONTENT', Blockly.Arduino.ORDER_ATOMIC) || '0';
   var checkbox_name = (block.getFieldValue('NEW_LINE') == 'TRUE');
 
+  var serialPins = Blockly.Arduino.Boards.selected.serialPins[serialId];
+  for (var i = 0; i < serialPins.length; i++) {
+    Blockly.Arduino.reservePin(block, serialPins[i][1],
+        Blockly.Arduino.PinTypes.SERIAL, 'SERIAL ' + serialPins[i][0]);
+  }
+
   if (checkbox_name) {
     var code = serialId + '.println(' + content + ');\n';
   } else {