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TCP Receive

Receive data over TCP/IP network from remote host

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  • TCP Receive block

Libraries:
Embedded Coder Support Package for STMicroelectronics STM32 Processors / STM32F4xx Based Boards
Embedded Coder Support Package for STMicroelectronics STM32 Processors / STM32F7xx Based Boards
Embedded Coder Support Package for STMicroelectronics STM32 Processors / STM32H7xx Based Boards
Embedded Coder Support Package for STMicroelectronics STM32 Processors / STM32F2xx Based Boards

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.

blocking mode

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.

non blocking mode

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 Outputs for Received Data.

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.

  • When DHCP is enabled with TCP/IP or UDP blocks in the model, the code waits in an infinite loop until IP is assigned to the board. Hence, user must ensure board is connected to router, if their model has any UDP/TCP block in their model with DHCP enabled.

Examples

Exchanging Ethernet Data with STM32F746G Discovery Board

Exchanging Ethernet Data with STM32F746G Discovery Board

Use Embedded Coder® Support Package for STMicroelectronics® STM32 Processors to run on the STM32F746G Discovery Board to send and receive the UDP and TCP messages.

Ports

Output

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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 Outputs for Received Data.

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

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 Outputs for Received Data.

Data Types: uint16

Parameters

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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.

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.

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.

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.

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

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

  • 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.

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

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Version History

Introduced in R2017a

See Also