Arduino: Timing Code with Millis() as a Stopwatch

Wed, 11 Dec 2013 12:25:22 +0000

Since most Arduino boards do not have debug capability, this limits the programmer to using Serial.prints. A useful piece of information might be knowing how long certain parts of code are running. Here’s a simple example that demonstrations:

How to properly use Serial.flush() (hint: it’s for TRANSMIT, not RECEIVE!)
How long Serial.print()s can “tie up” the Arduino.

At 9600 baud, you’ll see that the Arduino is only busy for about 20 milliseconds in the first chunk of code, but busy for 93 milliseconds in the next. That’s because the Arduino (since 1.0) started using a transmit-buffer. Did you know your code doesn’t wait for a Serial.print to finish?

millis cookbook. millis on Bald Engineer

Arduino: Timing Code with Millis() as a Stopwatch