improve ardiuno serial connection guide

Arduino/ODriveArduino/examples/ODriveArduinoTest/ODriveArduinoTest.ino

@@ -1,14 +1,38 @@
-
+// includes
 #include <SoftwareSerial.h>
 #include <ODriveArduino.h>
-
-// Printing with stream operator
+// Printing with stream operator helper functions
 template<class T> inline Print& operator <<(Print &obj,     T arg) { obj.print(arg);    return obj; }
 template<>        inline Print& operator <<(Print &obj, float arg) { obj.print(arg, 4); return obj; }
 
-// Serial to the ODrive
-SoftwareSerial odrive_serial(8, 9); //RX (ODrive TX), TX (ODrive RX)
-// Note: you must also connect GND on ODrive to GND on Arduino!
+
+////////////////////////////////
+// Set up serial pins to the ODrive
+////////////////////////////////
+
+// Below are some sample configurations.
+// You can comment out the default Teensy one and uncomment the one you wish to use.
+// You can of course use something different if you like
+// Don't forget to also connect ODrive GND to Arduino GND.
+
+// Teensy 3 and 4 (all versions) - Serial1
+// pin 0: RX - connect to ODrive TX
+// pin 1: TX - connect to ODrive RX
+// See https://www.pjrc.com/teensy/td_uart.html for other options on Teensy
+Stream& odrive_serial = Serial1;
+
+// Arduino Mega or Due - Serial1
+// pin 19: RX - connect to ODrive TX
+// pin 18: TX - connect to ODrive RX
+// See https://www.arduino.cc/reference/en/language/functions/communication/serial/ for other options
+// Stream& odrive_serial = Serial1;
+
+// Arduino without spare serial ports (such as Arduino UNO) have to use software serial.
+// Note that this is implemented poorly and can lead to wrong data sent or read.
+// pin 8: RX - connect to ODrive TX
+// pin 9: TX - connect to ODrive RX
+// SoftwareSerial odrive_serial(8, 9);
+
 
 // ODrive object
 ODriveArduino odrive(odrive_serial);