Counter Input

Read from one or multiple counter-input channels

• 

Libraries:
Simulink Desktop Real-Time

Description

The Counter Input block connects to and reads from specific counter-input channels into your Simulink^® model. After you have added a Counter Input block to your model, you can enter the parameters for its I/O driver.

Examples

Frequency Measurement

Measure input signal frequency by using Simulink Desktop Real-Time™.

• Open Script

PWM Frequency and Duty Measurement

Measure PWM signal frequency and duty using Simulink Desktop Real-Time™.

• Open Script

Ports

Output

Counter Data — Counter data read from input channels

vector

Data representing the state of a counter. The data type of the output values depends upon the capabilities of the board.

Data Types: single | double | int8 | uint8 | int16 | uint16 | int32 | uint32

Missed Ticks — Missed tick count (optional)

double

In Connected IO mode, returns the number of timer ticks that your model lags behind the real-time kernel. When the model lags by more than Maximum missed ticks, the software reports an error and simulation stops.

Dependency

When you select Show “Missed Ticks” port, this port is visible.

Data Types: double

Parameters

Install new board — Register a board

< no board selected > (default)

When you click Install new board, the software displays a list of manufacturers of supported boards. When you select a manufacturer, the software displays a list of boards available from that manufacturer. When you select a board, the software adds the board to the list of registered boards and makes that board the current board.

By default, the initial selection in the list of registered boards is < no board selected >.

For more information about driver support for I/O boards, see Hardware Support from Simulink Desktop Real-Time.

Dependency

When you select a board in the list of registered boards, the Delete current board and Board setup buttons are available.

Programmatic Use

Block Parameter: DrvName

Delete current board — Delete the current board

(button)

To delete the current board, click this button. The initial selection of the list of registered boards changes to < no board selected >.

Dependency

To activate this parameter, select a board in the list of registered boards.

When you delete the current board, the Delete current board and Board setup buttons are no longer available.

Programmatic Use

Block Parameter: DrvName

Board setup — Set up the board

(button)

To set up the board, click this button.

A board-specific dialog box opens to set up the board. For more information, see the board manufacturer documentation.

Dependency

To activate this parameter, select a board in the list of registered boards.

To deactivate this parameter, click Delete current board.

Programmatic Use

Block Parameter: DrvAddress

Block Parameter: DrvOptions

Sample time — Sample time of block

0.1 (default) | double

Enter a value, in seconds, that represents how frequently you want the block to execute and interact with the I/O hardware. The block synchronizes your model with the real-time clock at this sample rate.

If you are using a fixed-step solver, enter the value that you entered as the Fixed step size configuration parameter or an integer multiple of that value.

Programmatic Use

Block Parameter: SampleTime

Maximum missed ticks — Number of timer ticks by which your model can trail the kernel

10 (default) | integer

In Connected IO mode, enter the number of timer ticks that your model can lag behind the real-time kernel. When the model lags behind by this number or fewer timer ticks, the software assumes that the lag is temporary. It allows the model to catch up, even if the model misses some ticks. When the model lags by more than this number, the software reports an error and simulation stops.

In Run in Kernel mode, the software ignores this value.

Programmatic Use

Block Parameter: MaxMissedTicks

Show “Missed Ticks” port — Send number of missed ticks to port Missed Ticks

'off' (default) | 'on'

In Connected IO mode, select this check box to send the number of missed ticks to output port Missed Ticks.

In Run in Kernel mode, the Missed Ticks port is zero.

Programmatic Use

Block Parameter: ShowMissedTicks

Yield CPU when waiting — Yield CPU while kernel waits for hardware

'off' (default) | 'on'

In Connected IO mode, select this check box to grant other programs more CPU time while the kernel waits for a response from the hardware.

In Run in Kernel mode, the software ignores this value.

Programmatic Use

Block Parameter: YieldWhenWaiting

Input channels — Select counter-input channels

1 (default) | vector

Enter a channel vector that selects the counter input channels you are using on this board. The vector can be any valid MATLAB^® vector form.

For example, to select the first four counter-input channels on the board, enter:

[1,2,3,4]

or

[1:4]

Programmatic Use

Block Parameter: Channels

Reset after read — Counter-reset policy

never (default) | always | level | rising edge | falling edge | either edge

Determines whether the software resets the counter to zero after reading its value. From the list, select one of the following options:

• never — Do not reset after reading.

• always — Always reset after reading.

• level — Reset after reading if the block input is nonzero. Adds an input to the Counter Input block.

• rising edge — Reset after reading if the block input changes from zero to nonzero between the last two successive readings. Adds an input to the Counter Input block.

• falling edge — Reset after reading if the block input changes from nonzero to zero between last two successive readings. Adds an input to the Counter Input block.

• either edge — Reset after reading if the block input changes either from zero to nonzero or from nonzero to zero between the last two successive readings. Adds an input to the Counter Input block.

Programmatic Use

Block Parameter: ResetMode

Clock input source — Clock input that increments counter

input pin rising edge (default) | input pin falling edge | internal clock

Determines the clock input source to increment the counter. From the list, select:

• input pin rising edge — Clock edge low-to-high transitions

• input pin falling edge — Clock edge high-to-low transitions

• internal clock — Internal time base

  If you set the Gate input functionality parameter to enable when high, latch & reset on edge, or enable when low, latch & reset on edge, you can measure positive or negative pulse lengths in units of the internal time base. You can use this combination with National Instruments™ drivers for pulse width measurement.

Not all counter chips support selecting the input edge. In this case, only supported options appear in the list.

Programmatic Use

Block Parameter: CounterEdge

Gate input functionality — Action of counter-gate input pin

none (default) | enable when high | enable when low | start on rising edge | start on falling edge | reset on rising edge | reset on falling edge | latch on rising edge | latch on falling edge | latch & reset on rising edge | latch & reset on falling edge | enable when high, latch & reset on edge | enable when low, latch & reset on edge

Defines the action of the counter gate input pin. From the list, select:

• none — Enable counting unconditionally, ignoring gate input.

• enable when high — Disable counting when gate input is low and enable counting when gate input is high.

• enable when low — Disable counting when gate input is high and enable counting when gate input is low.

• start on rising edge — Disable counting until low-to-high gate transition occurs.

• start on falling edge — Disable counting until high-to-low gate transition occurs.

• reset on rising edge — Reset counter to zero when low-to-high gate transition occurs.

• reset on falling edge — Reset counter to zero when high-to-low gate transition occurs.

• latch on rising edge — Store count in register when low-to-high gate transition occurs. Return contents of register.

• latch on falling edge — Store count in register when high-to-low gate transition occurs. Return contents of register.

• latch & reset on rising edge — Store count in register, and then reset counter to zero when low-to-high gate transition occurs. Return contents of register.

• latch & reset on falling edge — Store count in register, and then reset counter to zero when high-to-low gate transition occurs. Return contents of register.

• enable when high, latch & reset on edge — Disable counting while gate input is low. Start counting when low-to-high gate transition occurs. Count while gate input is high. Store count in register, and then reset counter to zero when high-to-low gate transition occurs. Return contents of register.

  If you set the Clock input source parameter to internal clock, you can measure positive pulse lengths in units of the internal time base. You can use this combination with most National Instruments drivers for pulse width measurement.

• enable when low, latch & reset on edge — Disable counting while gate input is high. Start counting when high-to-low gate transition occurs. Count while gate input is low. Store count in register, and then reset counter to zero when low-to-high gate transition occurs. Return contents of register.

  If you set the Clock input source parameter to internal clock, you can measure negative pulse lengths in units of the internal time base. You can use this combination with National Instruments drivers for pulse width measurement.

Not all counter chips support all gate input modes. Only supported modes appear in the list.

Programmatic Use

Block Parameter: CounterGate

Output data type — Data type of block output

double (default) | single | int8 | uint8 | int16 | uint16 | int32 | uint32

From the list, select the type of data that the block outputs to the model. The valid values depend on the capabilities of the board.

Programmatic Use

Block Parameter: DataType

Version History

Introduced before R2006a

R2024b: Update to blocks with port names

In R2024b, when you enable optional ports, such as Show "Missed Ticks" port, these Simulink Desktop Real-Time™ block ports appear with labels.