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PWM

Generate pulse width modulated signal on analog output pin

  • Library:
  • Simulink Support Package for Arduino Hardware / Common

  • Arduino support package PWM block mask icon

Description

The PWM block generates square pulses of varying duty cycle depending on the input value sent to the block on the Arduino® hardware pin. This block enables a digital output to provide a range of different power levels, similar to that of an analog output.

For more information on how to select pins when you Simulink® model contains PWM, Standard Servo Read, Standard Servo Write, Continuous Servo Write, and Input Capture blocks, see Conflicting Pin Configurations on Arduino Timer.

Limitations

  • If you use the PWM block along with the Serial Receive and Serial Transmit blocks in a Simulink model, use longer sample times to avoid overruns.

  • This table specifies the upper limit of the output frequency that can be generated on the digital pins of the following Arduino boards.

    Arduino Board TypeArduino Pin NumberGenerated PWM Output Frequencies (Hz)
    Uno, Nano 3.05, 6980.4
    3, 1131372.55, 3921.16, 980.4, 490.2, 245.1, 122.55, 30.64
    Mega 2560/ADK4, 13980.4
    9, 1031372.55, 3921.16, 980.4, 490.2, 245.1, 122.55, 30.64
    Leonardo, Robot Control Board, Robot Motor Board, Micro3, 11980.4

Ports

Input

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The value sent to the block input determines the width of the square wave, called duty-cycle, that the Arduino hardware outputs on the specified PWM pin.

For example:

  • Sending the maximum value, 255, to the block input produces 100% duty-cycle, which results in full power on the PWM pin.

  • Sending the minimum value, 0, to the block input produces 0% duty-cycle, which results in no power on the PWM pin.

  • Sending an intermediate value to the block input produces a proportional duty-cycle and power output on the PWM pin. For example, sending 204 to the block input produces 80% duty cycle and power (204/255 = 0.8).

  • Sending out-of-range values, such as 500 or -500, to the block input has the same effect as sending the maximum or minimum input values, respectively.

The block input port inherits the data type of the upstream block, and internally converts it to uint8.

Data Types: uint8

Parameters

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Specify the Arduino hardware board pin number to which the PWM input signal is connected.

Note

Do not assign the same pin number to multiple blocks within a model.

For more information on how to assign pins or view the pins for the PWM block, see Pin Mapping for Arduino Timer Dependent Blocks.

Click this button to view the pin mapping table associated with the Arduino hardware board you select.

Configure the frequency of the PWM signal.

When you set the Frequency as:

  • Default –– The block generates PWM signal with default frequency. For more information on default PWM frequencies and pins that support PWM on different Arduino boards, see PWM supported pins and frequencies.

  • Specify –– Using this parameter, you can specify the frequency of the PWM signal. Using this option enables the Desired(Hz) and Achievable(Hz) parameters. In the Desired(Hz) parameter, specify the desired frequency of the PWM signal. The block generates the PWM signals with achievable frequency that is closest to the frequency specified in the Desired(Hz) parameter.

Note

In Connected I/O mode, you cannot use the Specify option. The block generates the PWM signal only with default frequencies.

Specify the desired output frequency of the PWM signal.

Dependencies

To enable this parameter, set Frequency to Specify.

The block generates the PWM signals with the frequency that is closest to the frequency specified in the Desired(Hz) parameter.

Dependencies

To enable this parameter, set Frequency to Specify.

Introduced in R2012b