Input Capture

Measure frequency and duty cycle of external input signal

Since R2020b

Add-On Required: This feature requires the Simulink Support Package for Arduino Hardware add-on.

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Libraries:
Simulink Support Package for Arduino Hardware / Common

Description

The Input Capture block measures the frequency and duty cycle of the external input signal on the digital pin of the Arduino^® hardware board. The block utilizes the timer counters available on the Arduino hardware board along with the interrupt service routines to compute the frequency and duty cycle of the external input signal.

You can run a Simulink^® model containing Input Capture block in Connected IO mode on Arduino boards.

For more information on the conflicting usage of digital pins for a Simulink model that uses one or more combination of PWM, Standard Servo Read, Standard Servo Write, Continuous Servo Write, and Input Capture blocks, see the Conflicting Pin Configurations on Arduino Timer section.

Limitations

This table lists the maximum measurable frequency and their corresponding measurable duty cycle range for the Arduino boards.

Arduino Board Architecture	Maximum Measurable Frequency	Measurable Duty Cycle Range
AVR	50KHz	20% to 80%
SAMD	400KHz
SAM	400KHz
Nano 33 BLE Sense	50KHz

This table lists the maximum and minimum frequency and duty cycle that can be measured using the Arduino-compatible Teensy 4.0 and 4.1 boards.

Arduino Board Architecture	CPU Frequency (MHz)	Minimum and Maximum Measurable Frequency Range	Measurable Duty Cycle Range
Teensy 4.0 and 4.1	1008	1.2KHz - 1MHz	20% to 80%
	960
	912
	816
	720
	600
	528
	450
	396	1.2KHz - 500KHz
	150	1.2KHz - 250KHz
	24	200Hz - 5KHz

Ports

Output

Frequency — Frequency of external input signal

scalar

The block outputs the frequency of the external input signal in Hertz.

Data Types: uint32

Duty Cycle — Duty cycle of external input signal

1 to 100

The block outputs the duty cycle of the external input signal as a percentage.

Data Types: uint8

Parameters

Input capture pin number — Pin to which external input signal is connected

48 (default) | scalar

Enter the Arduino hardware board pin number to which the external input signal is connected.

Note

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

To know more on how to assign pins or to view the fixed pins for the Input Capture block, see Pin Mapping for Arduino Timer-Dependent Blocks.

Sample Time — Time interval at which external input signal is read

0.1 (default) | scalar

Enter the time interval in seconds at which the block reads the external input signal from the specified pin number.

Version History

Introduced in R2020b