A simple command processor
So far, you have been creating sketches and uploading them where they run
independently. You can also interact with the sketch while it is running
by taking advantage of the (virtual) UART connection provided by the USB
connection with the PC.
Set up the circuit as shown.
Copy and upload the code below, then open the serial monitor and check
that the commands work as expected.
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81 | const int ledPin = 13; // Onboard LED
const int REDLed = 3; // PINs for RGB LED
const int GREENLed = 4;
const int BLUELed = 5;
const unsigned long baudrate = 9600;
char command ; // Stores the command read from the serial channel
void setup() // IO Initialisation
{
Serial.begin(baudrate); // Identifies USB Virtual Comport (VCP)
pinMode(ledPin, OUTPUT); // Configure GPIO pins
pinMode(REDLed, OUTPUT);
pinMode(GREENLed,OUTPUT);
pinMode(BLUELed, OUTPUT);
digitalWrite(REDLed, LOW); // Turn the RGB Led OFF
digitalWrite(GREENLed, LOW);
digitalWrite(BLUELed, LOW);
} // end of setup
void loop()
{
if (Serial.available()) // Read command char from VCP
{
command = (char)Serial.read();
Serial.print("Command Received >> ");
Serial.println(command);
switch (command)
{
case '1' : { // Red on
digitalWrite(REDLed, HIGH);
digitalWrite(GREENLed, LOW);
digitalWrite(BLUELed, LOW);
break;
}
case '2' : { // Green on
digitalWrite(REDLed, LOW);
digitalWrite(GREENLed, HIGH);
digitalWrite(BLUELed, LOW);
break;
}
case '3' : { // Blue
digitalWrite(REDLed, LOW);
digitalWrite(GREENLed, LOW);
digitalWrite(BLUELed, HIGH);
break;
}
case '4' : { // Yellow
digitalWrite(REDLed, HIGH);
digitalWrite(GREENLed, HIGH);
digitalWrite(BLUELed, LOW);
break;
}
case '5' : { // White
digitalWrite(REDLed, HIGH);
digitalWrite(GREENLed, HIGH);
digitalWrite(BLUELed, HIGH);
break;
}
default : { // Set LED OFF
digitalWrite(REDLed, LOW);
digitalWrite(GREENLed, LOW);
digitalWrite(BLUELed, LOW);
}
} // End processing received command
digitalWrite(ledPin, HIGH); // Blink onboard LED to show activity
delay(200);
digitalWrite(ledPin, LOW);
delay(200);
Serial.println("\n << Command Complete >> ");
} // End of serial data available
}
|
- Change the command set to 'A', 'B', 'C', 'D', ‘E’ and, in addition to
setting the RGB LED, get the Arduino to respond with a short message,
say Processing Command X when commands
are received. Use the terminal application Realterm
to do the same thing – (it is much better than the Arduino Monitor).