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In the first lessons, you've had the Maker Board running the commands as fast as it can. In the rest of these programs, you will control the speed and order in which the commands execute. Think carefully about how delays fit in with your code, because two commands next to each other will execute so quickly to seem simultaneous. Without a delay, something can happen so quickly that you won't see anything change, which makes those issues even harder to troubleshoot.

/* * In this lesson, you'll add a delay to the previous code, which tells * the microcontroller to pause for a certain amount of time. This will * stop the flickering effect by leaving the words drawn on the * screen for longer before clearing them and re-writing. */ #include "MakerScreenXVI.h" MakerScreenXVI lcd; void setup() { lcd.begin(); lcd.backlightOn(); } void loop() { lcd.clear(); lcd.print("Hello World!"); /* * Delay tells the code to halt execution for a period of time. It is * measured in milliseconds (ms), or thousandths of a second. This delay * is for 100 ms: 1/10th of a second. */ delay(100); } /* * Controlling how fast your code executes is important. * * Because the processor is so fast, it can do things that humans cannot, * but it does not operate with any natural delays like people do. * To make it perform actions in order and for a given amount of time, * you have to tell it when to pause. Imagine a song played at 100X speed- * it wouldn't sound very good. * * Delay is one method of doing so. It leaves the controller in whatever * state it was in when you arrive at the command, and does nothing * for the duration of time you specify. * * In this build, you'll see have different approaches for controlling * timing that do not stop the processor from doing things while * waiting for time to pass. */ //(c) 2017 Let's Start Coding. License: www.letsstartcoding.com/bsdlicense

Try moving the delay line to somewhere else in the code, like between the lcd.clear() line and the lcd.print() line. The entire program is still running, but you do not pause after printing Hello World, so it is immediately cleared before you see it. See how the placement of a delay makes a big difference in a program?

Restore the code to it's original state. Now type a new delay(100); between the lcd.clear() line and lcd.print() line. How does that affect the program?