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Packet Input

Read binary data or a CAN message from a communication channel

Description

Read unformatted binary data from a port or file. After you add a Packet Input block to your model, double-click the block to set its parameters.

The driver must be one of:

  • Standard Devices > Serial Port

  • Standard Devices > UDP Protocol

  • Standard Devices > File

  • Vector > CAN Device

When you install a UDP device, enter port addresses in decimal format in the Standard Devices UDP Protocol dialog box.

Ports

Output

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Data values that were received from the communication channel as unformatted binary data.

This port signals 1 if the block has new data available and 0 otherwise.

Dependency

When you select Show "Data Ready" port, this port is visible.

This port signals 1 if a data error occurs and 0 otherwise.

Dependency

When you select Show "Data Error" port, this port is visible.

This port shows the timestamp for the CAN message packets.

Dependency

When you select Show packet timestamp port, this port is visible.

In normal or accelerator modes, 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

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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 >.

Dependency

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

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.

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.

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.

In normal or accelerator modes, enter the number of timer ticks that your model can lag behind the real-time kernel. When the model lags by this number or fewer, 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 external mode, the software ignores this value.

In normal or accelerator modes, select this check box to send the number of missed ticks to output port Missed Ticks.

In external mode, the Missed Ticks port is zero.

In normal or accelerator modes, select this check box to grant other programs more CPU time while the kernel waits for a response from the hardware.

In external mode, the software ignores this value.

Enter the ID of the packet to process. If your protocol does not have packet IDs, this parameter is disabled.

Select this check box if Packet identifier is an extended identifier.

Enter the number of bytes expected in each input packet. This number must match the number of bytes required by the type specifications in Block output data types.

One or more character vectors that specify how the data in each packet is to be typed and grouped for input to the application. The Packet Input block has an output port corresponding to each character vector in Block output data types. Changing the number of character vectors changes the number of output ports.

Each character vector has the format [n*]datatype. The data that the character vector describes has the type specified by datatype and the width specified by n. If n is not specified, the width is 1. For example, 'double' means one double value, and '4*int8' means a vector of four int8 values. You can also type 'CAN_MESSAGE' to specify a single CAN_MESSAGE value.

By providing a cell array of such character vectors, you can convert an input packet into the types required, packaged into vectors. For example, specifying {'int16','int16','double'} creates three ports. The first and second each output an int16 value, and the third outputs a double. Specifying {'2*int16','double'} creates two ports: a vector of two int16 values, and a scalar double.

The block forces an out-of-range value to the maximum value for that data type.

From the list, select:

  • Little Endian (default) — Send multibyte values in little-endian format.

  • Big Endian — Send multibyte values in big-endian format.

When you select this check box, the block makes visible the output port Data Ready. This port signals 1 when the block has new data available and 0 otherwise.

When you select this check box, the block makes visible the output port Data Error. This port signals 1 when a data error occurs and 0 otherwise.

When you select this check box, the block makes visible the output port Timestamp. This port shows the timestamps for the CAN message packets. If your protocol does not have packet timestamps, the block ignores this value.

Model Examples

Introduced in R2007b

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