Introduction to data types in the Arduino

Introduction to data types in the Arduino - SparkFun Electronics #data

Next, let’s look at the serial port output. What’s the deal with the squares instead of a number for the printed variable values? That happens because the Serial.print() function changes the way it operates based on the type of data which is passed to it. For an 8-bit value (be it a char or byte ), it will simply pipe out that value, in binary. The serial console is then going to try to interpret that data as an ASCII character , and the ASCII characters for 1, 2, and 3 are “START OF HEADING”, "START OF TEXT", and "END OF TEXT". Hm. Not particularly useful, are they, nor easy to display in one character? Hence the square: the serial console is throwing up its hands and saying, "I don't know how to print this, so I made a square for you." So, lesson one in Arduino datatype finesse: To get the decimal representation of an 8-bit value from Serial.print(), you must add the ‘DE...

Full article: http://www.sparkfun.com/tutorials/317