SunFounder R3, Руководство пользователя

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SunFounder uno-and-mega-kit
(continued from previous page)
break ;
case 2 :
clockwise(rank2); // When stat=2, set the rotate speed of the motor as rank1=200
break ;
case 3 :
clockwise(rank3); // When stat=3, set the rotate speed of the motor as rank1=250
break ;
default :
clockwise( 0 );
}
The
switch
statement, like the
if
statement,
switch case
allows the programmer to control the flow of the
program with different code executed under various conditions. In particular, the switch statement compares the value
of a variable with the value specified in the case statement. When a case statement is found whose value matches the
value of a variable, the code in that case statement is run. If there is no
break
statement, the
switch
statement will
continue to execute the following expression until
break
or until it reaches the end of the switch statement.
In this part of the code.
• If stat = 1, let the fan rotate at speed rank1(150).
• If stat = 1, let the fan rotate at speed rank2(200).
• If stat = 1, let the fan rotate at speed rank3(250).
• If stat = 0, let the fan rotate at speed 0.
clockwise() function
void clockwise ( int Speed) //
{
analogWrite (motorIn1, 0 );
analogWrite (motorIn2,Speed);
}
This function sets the speed of the motor: write
Speed
to pin 9 and 0 to pin 10. The motor rotates in a certain direction
with the value of
Speed
.
7.22.7 Experiment Summary
In this experiment, you can also control the motor to rotate or not. Just connect pin 1, 2EN of the L293D to an I/O
port of the control board. Set 1, 2EN as High level, and the motor will start rotating; set it as Low level, it will stop the
rotating.
7.23 Lesson 23 Simple Creation - Digital Dice
7.23.1 Introduction
In previous experiments, we learned how to use a 7-segment display and control LEDs by a button. In this lesson, we
will use a 7-segment display and a button together to create a simple digital dice.
7.23. Lesson 23 Simple Creation - Digital Dice 337