TCP Receive

Receive data over TCP/IP network from remote host

Add-On Required: This feature requires the Simulink Coder Support Package for STMicroelectronics Nucleo Boards add-on.

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Libraries:
Simulink Coder Support Package for STMicroelectronics Nucleo Boards / STM32F7
Simulink Coder Support Package for STMicroelectronics Nucleo Boards / STM32H7

Description

The TCP Receive block receives data from a remote host or other target hardware over a network. When you set Connection mode to Server, you must provide the Local IP Port. The Local IP Port acts as the listening port of the TCP/IP server. When you set Connection mode to Client, you must provide the Server IP Address and the Server IP Port on the server from which to receive the data. The server must be up and running before deploying the model that contains the TCP Receive block to the target.

The block accepts data either in blocking mode or in non-blocking mode. In blocking mode, the model blocks the execution while it waits for the requested data to be available. In non-blocking mode, the model runs continuously. To set the block in blocking mode, select the Wait until data received option.

In blocking mode, the model blocks the execution while it waits for the requested data to be available.

At time step 1, the block requests four data values, and the TCP/IP receive buffer gets four data values. The execution runs.

At time step 2, the block requests for data again, but the TCP/IP receive buffer gets only three data values. The execution pauses until the buffer receives the fourth data value or the time-out value elapses. Then, the execution resumes.

At time step 3, the block requests for data, and the buffer receives five data values. The block returns the first four data values, and the remaining data value is used in the next receipt cycle.

In non-blocking mode, the model runs continuously.

At time step 1, the block requests data, and the buffer gets four data values. The block changes the Status port value to 0, indicating that new requested data is available. The Data port, at this point, contains the newly received data values. The block resets the Data port value to 0.

At time step 2, the block requests data again, but the buffer gets only three values. The block cannot return a value of 3 because the data size is specified as 4. Therefore, the block sets the Status port value to 1, indicating that there is no new data. All values on the Data port become 0. The buffer, at this point, has three data values. However, during this phase, the execution does not stop unlike in the blocking mode.

At time step 3, the buffer has five data values, and the block returns the first four data values in the order received and changes the Status port value to 0. The remaining data value is used in the next receipt cycle.

At each time step, the Data port outputs data as a vector of the size that you specify in the Data size (N) parameter. The Status port outputs 0 or a nonzero value indicating whether new data is received. 0 at the Status port indicates that a valid data is received. For more information, see .

Note

In some cases, the antivirus or firewall may block the TCP traffic. If so, configure the antivirus or firewall to allow the traffic for a specific IP port number.

Ports

Output

Data — Output data

vector

At each time step, the port outputs data as a vector of the size that you specify in the Data size (N) parameter. For more information, see .

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

Status — Requested data received at given time step

scalar

At each time step, when the length of data received is greater than or equal to the length specified in the Data size (N) parameter, the port outputs 0. A value of 0 indicates that the requested data is received at the given time step. Otherwise, it outputs a nonzero value, indicating that no new data is received.

For more information, see .

Data Types: uint16

Parameters

Connection mode — Set the block as server or client

Server (default) | Client

Set the block as TCP/IP server or client.

When you set this parameter to Server, you must provide a Local IP Port. The local port acts as the listening port on the TCP/IP server.

When you set this parameter to Client, you must provide the Server IP Address and the Server IP Port on the TCP/IP server from which you want to receive the data.

Local IP Port — IP port on receiving host from which data is received

25001 (default) | any integer from 1 to 65,535

This local port number acts as a listening port on the TCP/IP server. Match the local port number with the remote port number of the sending host.

Server IP Address — Remote IP address of server from which data is received

192.168.1.2 (default) | any valid IP address

Specify the IP address of the sending server from which the data is received.

Dependencies

This parameter appears only when you set the Connection mode parameter to Client.

Server IP Port — Remote IP port on server from which data is received

25000 (default) | any integer from 1 to 65,535

Specify port number on the sending server from which data is received.

Dependencies

This parameter appears only when you set the Connection mode to Client.

Data type — Data type of received data

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

Specify the type of the data the block receives from the sending host. The size of each element depends on its data type.

Data size (N) — Number of data bytes in received data

1 (default) | any positive integer

Specify number of data bytes to receive at each time step.

Wait until data received — Wait until requested data is available

off (default) | on

• When you select this parameter, the read operation runs in blocking mode. The read operation is blocked while waiting for the requested data to be available. If data is available, the Data port outputs data. If data is not available, the Data port waits for data.

  A task overrun occurs if the target hardware is still waiting for the data to be available when the next read operation is scheduled to begin.

  To fix overruns:

  • Increase the time step by using the Sample time parameter.

  • Reduce the length of data requested by using the Data size (N) parameter.

• When you clear this parameter, the read operation runs in non-blocking mode. When reading data, if data is not available, the Data port contains the data received in the previous time step. The Status port outputs 0. In this mode, the block does not wait for the requested data to be available.

Output error status — Option to display the error status during data transmission

on (default) | off

Select this option to display the error status during data transmission.

When you select the Output error status parameter, the block configures an output port. The port on the block is labeled as Status, indicating that the block outputs the status of the read operation at the output port.

Sample time — Interval at which block reads data from sending host

-1 (default) | nonnegative value

When you set this parameter to -1, Simulink® determines the best sample time for the block based on the block context within the model.

More About

Outputs for Received Data

The values at the output ports vary depending on whether the length of data received is less than, greater than, or equal to the length of requested data.

• Length of data received = Data size (N): The Data port outputs data as a vector of the size specified in the Data size (N) parameter. The Status port outputs 0, indicating that the requested data is received.

  Suppose that the Data size (N) parameter is set to 4, and the length of the data received is also 4. In this case, the Data port outputs a data vector of size 4 filled with the received data bytes. The Status port outputs 0.

  

• Length of data received < Data size (N): The Data port outputs data as a vector of the size specified in the Data size (N) parameter filled with zeros. The Status port outputs a nonzero value, indicating that no new data is received.

  Suppose that the Data size (N) parameter is set to 4, and the length of data received is 3 bytes. In this case, the Data port outputs a data vector of size 4. All the spaces in the vector are filled with zeros. The Status port outputs a nonzero value.

• Length of data received > Data size (N): The Data port outputs a data vector of the size specified in the Data size (N) parameter. The vector contains only the first N bytes from the data. The remaining bytes are emitted along with the data bytes in the next time step. The Status port outputs 0, indicating that the requested data is received.

  Suppose that the Data size (N) parameter is set to 4, and the length of data received is 5 bytes. In this case, the Data port outputs a data vector of size 4. The vector contains only the first 4 bytes from the received data. The fifth byte is emitted along with the data bytes in the next time step. The Status port outputs 0.

  

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2017a