PWM Interface
Simulate pulse width modulation (PWM) output from hardware
- Library:
SoC Blockset / Peripherals
Description
The PWM Interface block simulates the PWM output of a hardware board. This blocks gets duty cycle data messages from a connected PWM Write block that can either generate a switching pulse-width-modulated waveform or pass the duty cycle value to the output.
Ports
Input
Output
PWM — Pulse-width-modulated signal
scalar
This port outputs the pulse-width-modulated rectangular wave defined by the dCycle input port.
Dependencies
To enable this port, set the Output mode parameter to
Switching.
Data Types: double
~PWM — Complimentary pulse-width-modulated signal
scalar
This port outputs the complimentary PWM signal.
Dependencies
To enable this port, set the Output mode parameter to
Switching.
Data Types: double
dCycle — Analog approximation of pulse-width-modulated signal
scalar
This port emits the averaged value of the PWM waveform, which is a pass-through of the duty cycle input value. This image shows the average output signal equivalent to the PWM output.
Dependencies
To enable this port, set the Output mode parameter to
Average.
Data Types: double
event — Event emitted on each PWM cycle
scalar
This port sends a message during each PWM output event that can connect to the start port of the ADC Interface block to synchronize ADC and PWM events in closed-loop systems.
Data Types: rteEvent
Parameters
PWM Period (s) — Period of PWM waveform
50e-6 (default) | positive scalar
Specify the period of the PWM waveform in seconds.
Output mode — Output mode
Switching (default) | Average
Simulate the output signal as either a true PWM waveform by specifying
Switching or as the average of the duty cycle by specifying
Average.
Example: 50e-6
Counter mode — Counter waveform
Up-Down (default) | Up | Down
The counter mode specifies the shape of the underlying sawtooth waveform that drives
the PWM output signal inside the PWM module. In Down mode, the
sawtooth counter counts increments to the maximum and then resets to zero on each
period. In UP mode, the sawtooth counter decrements to zero then
resets to the maximum. In Up-Down mode, the sawtooth counter
oscillates from zero to the maximum value.
Example: Up
Sampling mode — Sampling mode
End of PWM period (default) | Mid of PWM period | Mid or End of PWM period
Specify the time at which the input duty cycle is sampled.
Example: Mid or End of PWM period
Dead time (s) — Dead band switching delay
1e-6 (default) | positive scalar
A time delay is introduced between turning off one of the transistors of a leg of an inverter and turning on the other transistor to ensure that a dead short circuit does not occur. This diagram shows the expected duty cycle and the delay introduced by the transistor switching the dead band.
Example: 450e-9
Event trigger mode — Trigger mode relative to PWM waveform
End of PWM period (default) | Mid of PWM period | Mid or End of PWM period
Specify when this block triggers an event relative to the PWM waveform.
Example: Mid or End of PWM period