Digital Input

Read from one or multiple digital input channels

• 

Libraries:
Simulink Desktop Real-Time

Description

The Digital Input block connect to and reads from specific digital lines or channels into your Simulink^® model. After you have added a Digital Input block to your model, you can enter the parameters for its I/O driver.

Examples

Real-Time Controller

Build a simple closed-loop real-time controller by using Simulink Desktop Real-Time™.

• Open Script

Real-Time Filter

Build a real-time filter using DSP System Toolbox™ and Simulink Desktop Real-Time™.

• Open Script

Ports

Output

Digital Data — Digital data read from input channels

vector

The data type and range of the output values depend 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 digital input channels

1 (default) | vector

Enter a channel vector that selects the digital input channels you are using on this board. The vector can be any valid MATLAB^® vector form. For example, to select the first eight digital input channels, enter:

[1,2,3,4,5,6,7,8]

or

[1:8]

If you want to use the first four digital input lines, enter:

[1,2,3,4]

If you have one 8-bit digital channel, enter [1]. If you have two 8-bit digital channels, enter [1 9], and from the Channel mode list, select Byte.

Programmatic Use

Block Parameter: Channels

Channel mode — Mode of representing the input lines

Bit (default) | Byte

From the list, select one of the following options:

• Bit — Returns a value of 0 or 1.

• Byte — Groups eight digital lines into one digital channel. Returns a value of 0–255.

Programmatic Use

Block Parameter: BitMode

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.