Example Code for Arduino-PWM Output

Hardware Preparation

• DFRobot Beetle RP2040, 1, Purchase Link
• USB Type-C Cable, 1

Software Preparation

• Arduino IDE: Download Link
• Raspberry Pi Pico/RP2040 SDK: Installed via Arduino Boards Manager (see Getting Started)

Wiring Diagram

No external wiring required (uses the onboard LED).

Other Preparation Work

1. Open Arduino IDE.
2. Select "DFRobot Beetle RP2040" as the development board.
3. Connect the Beetle RP2040 to your computer.

Sample Code

Function: use PWM to drive the onboard LED to present a breathing lighting effect

void setup(){
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop(){

byte value;

  for (value=0; value<255; value++)
  { 
    analogWrite(LED_BUILTIN, value);
    delay(10);
  } 

  for (value=255; value>0; value--)
  { 
    analogWrite(LED_BUILTIN, value);
    delay(10);
  }  
}

Result

After downloading the code, the onboard green LED gradually gets bright and then fades.

Additional Information

• PWM works by varying the duty cycle (percentage of time the signal is high) of a digital signal.
• The analogWrite() function takes a value between 0 (0% duty cycle, LED off) and 255 (100% duty cycle, LED full brightness).