PWM Interface

Simulate pulse width modulation (PWM) output from hardware

Since R2020b

• 

Libraries:
SoC Blockset / Peripherals
C2000 Microcontroller Blockset / Test Bench Blocks
Embedded Coder Support Package for Infineon AURIX TC3x Microcontrollers / Test Bench Blocks
Embedded Coder Support Package for Infineon AURIX TC4x Microcontrollers / Test Bench Blocks

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

msg — SoC message data

numeric vector

This port receives the duty cycle data from the msg port of a connected PWM Write block.

Data Types: SoCData

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.

Dependencies

To enable this port, the Type parameter must be set to ADC start or ADC start and PWM interrupt.

Data Types: rteEvent

eventn — Replicate event emitted on each PWM cycle

scalar

This port creates a replica port of the event output port to coordinate multiple ADC modules with the PWM module.

Dependencies

To enable this port, set the Type parameter to ADC start or ADC start and PWM interrupt and the Number of replicas parameter to a value greater than or equal to 2.

Data Types: rteEvent

interrupt — Interrupt event emitted on each PWM cycle

scalar

This port sends a message during each PWM output event that can connect to the Task Manager block to trigger other tasks in response to the PWM output update.

Dependencies

To enable this parameter, set the Type parameter to PWM interrupt or ADC start and PWM interrupt.

Data Types: rteEvent

Parameters

Main

PWM waveform period (s) — Period of PWM waveform

50e-6 (default) | positive scalar

Specify the period of the PWM waveform in seconds.

Note

For PWM waveform period (s) of 10ns, the duty cycle must be greater than 1%.

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: Switching

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 Up mode, the sawtooth counter increments to the maximum and then resets to zero on each period. In Down 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 or End of PWM period | Immediate (at compare matches)

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

PWM Output

At position of period — Signal change at position in period

High | Low | Change | NoChange

Specify the state of the PWM waveform signal at the position in the waveform relative to the total period. When set to High or Low, the waveform output changes to 1 or 0, respectively. When set to Change, the waveform inverts the current value. When set to NoChange, the waveform does not change. The position can either be the start or mid point of the PWM waveform. This table gives the default settings for these parameters.

Parameter	Default
At start of period	High
At mid of period	NoChange

Dependencies

At mid of period is only available when the Counter mode parameter is set to Up-Down.

At compare n — Signal change at comparator n trigger

High | Low | Change | NoChange

Specify the state of the PWM waveform signal when the internal PWM counter triggers comparator n. When set to High or Low, the waveform output changes to 1 or 0, respectively. When set to Change, the waveform inverts the current value. When set to NoChange, the waveform does not change. Two comparators, 1 and 2, are available to modify the PWM signal. This table gives the default settings for these parameters.

Parameter	Default
At compare 1	Low
At compare 2	NoChange

Dependencies

At compare 1 and At compare 2 parameters are only available when the Counter mode parameter is set to Up or Down.

At compare n direction count — Signal change at comparator n trigger

High | Low | Change | NoChange

Specify the state of the PWM waveform signal when the internal PWM counter crosses the comparator n value in the specified direction. When set to High or Low, the waveform output changes to 1 or 0, respectively. When set to Change, the waveform inverts the current value. When set to NoChange, the waveform does not change. Two comparators, 1 and 2, are available to modify the PWM signal. This table gives the default settings for these parameters.

Parameter	Default
At compare 1 up count	Low
At compare 1 down count	High
At compare 2 up count	NoChange
At compare 2 down count	NoChange

Dependencies

These arguments are only available when the Counter mode parameter is set to Up-Down.

Phase

Phase offset in degree (0-360) — PWM waveform offset

scalar from 0 to 360

Specify the phase of the PWM waveform relative period of waveform. The phase is represented as a scalar between 0 to 360 degrees.

Event

Type — Type of events to generate

ADC start (default) | PWM interrupt | ADC start and PWM interrupt

Specify the types of events on which to generate events. When the Typevalue is set to:

• ADC start — Generate an event to trigger the start ADC conversion.

• PWM interrupt — Generate an interrupt event to trigger the start of a task.

• ADC start and PWM interrupt — Generate events for both ADCs and tasks.

Example: ADC start and PWM interrupt

ADC start condition — Trigger mode relative to PWM waveform

End of PWM period (default) | Mid of PWM period | Mid or End of PWM period | Compare 1 up count | Compare 1 down count | Compare 2 up count | Compare 2 down count

Specify when this block triggers an event relative to the PWM waveform.

Example: Mid or End of PWM period

Dependencies

To enable this parameter, the Type parameter must be set to ADC start or ADC start and PWM interrupt.

Generate on — Generate event on multiple of PWM update

1st event (default) | nth event | 16th event

Specify to generate and output an ADC trigger event on the specified multiple of the PWM vent. For example, if Generate on is set to the 6th event, the PWM Interface block receives 6 messages updates the output 6 times before generating an ADC event message.

Example: 4th event

Dependencies

To enable this parameter, the Type parameter must be set to ADC start or ADC start and PWM interrupt.

Number of replicas — Generate replica event ports

1 (default) | integer from 1 to 16

Generate replica ADC event ports and events on the block. Use this coordinate the triggering of multiple ADCs modules from a single PWM Interface block.

Example: 4

Dependencies

To enable this parameter, the Type parameter must be set to ADC start or ADC start and PWM interrupt.

PWM interrupt condition — Trigger mode relative to PWM waveform

End of PWM period (default) | Mid of PWM period | Mid or End of PWM period | Compare 1 up count | Compare 1 down count | Compare 2 up count | Compare 2 down count

Specify when this block triggers an interrupt event relative to the PWM waveform.

Example: Mid or End of PWM period

Dependencies

To enable this parameter, the Type parameter must be set to PWM interrupt or ADC start and PWM interrupt.

Interrupt latency (s) — Interrupt generation latency

0 (default) | positive number

Specify the time required by the PWM hardware module from the completion of the output update to the generation of the interrupt in software.

Example: 0.00001

Dependencies

To enable this parameter, the Type parameter must be set to PWM interrupt or ADC start and PWM interrupt.

Generate on — Generate event on multiple of PWM update

1st event (default) | nth event | 16th event

Specify to generate and output a PWM interrupt trigger event on the specified multiple of the PWM vent. For example, if Generate on is set to the 6th event, the PWM Interface block receives 6 messages updates the output 6 times before generating an PWM interrupt event message.

Example: 4th event

Dependencies

To enable this parameter, the Type parameter must be set to PWM interrupt or ADC start and PWM interrupt.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using Simulink® Coder™.

To automatically generate C code for your design, and execute on an SoC device, use the SoC Builder tool. To generate and execute C code for your SoC models, Embedded Coder^® features are required. For more information on generating code for SoC designs, see Use SoC Builder to Generate SoC Design.

Version History

Introduced in R2020b