WiFi TCP/IP Receive

Receive data over TCP/IP network from remote host on wireless network

Add-On Required: This feature requires the Simulink Support Package for Arduino Hardware add-on.

Libraries:
Simulink Support Package for Arduino Hardware / WiFi

Description

The WiFi TCP/IP Receive block receives data from a remote host or other hardware over a wireless network. When you set Connection mode to Server, you must provide the Local IP port. The Local IP port acts as a listening port on the TCP/IP server. When you set Connection mode to Client, you must provide the Remote IP address and the Remote IP port of the TCP/IP server to receive data.

The block accepts data either in Blocking Mode or in Non-Blocking Mode. The block has two output ports, Data and Status. The Data port outputs requested data at each time step. The Status port indicates whether the new data at the specified time step is received.

You can run a Simulink^® model containing WiFi TCP/IP Receive block in Connected IO mode on Arduino^® boards.

Note

ESP32 and ESP8266 boards are not supported in Connected IO mode.

For more information about the fixed ports and the allocated pins for the block, see Pin Mapping for Arduino Timer Independent Blocks.

Note

If you are having trouble using TCP to communicate with a computer, antivirus or firewall software might be blocking TCP traffic. If so, configure the software to allow the traffic for a specific IP port number.

Supported Hardware

You can use the WiFi TCP/IP Receive block only with the following hardware:

ESP8266
WiFi Shield
MKR1000
MKR WIFI 1010
Nano 33 IoT
Arduino compatible ESP32 – WROOM board
Arduino compatible ESP32 – WROVER board

Limitations

When using ESP8266 hardware, a model can have only one WiFi TCP Receive, WiFi TCP Send, WiFi UDP Receive, or WiFi UDP Send block.
When using WiFi Shield, the Connection mode set for all the WiFi TCP Send blocks and WiFi TCP Receive blocks in a model must be same. The WiFi TCP blocks cannot act as servers and clients in a model simultaneously.
The maximum number of connections allowed for different ports on WiFi TCP Receive blocks and WiFi TCP Send blocks in a model is two for WiFi shield, seven for MKR1000, and one for ESP8266. If the model uses External mode over Wi-Fi^® or includes a WiFi ThingSpeak Read block or WiFi ThingSpeak Write block, one TCP port is reserved for each from the maximum allowed connections.

Ports

Output

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Data — Output data
vector

At each time step, the port outputs data as a vector of the size specified in the Data size (N) parameter. The data is received in little-endian format. To convert it to a big-endian format, do any of the following:

Place a Byte Reversal block immediately after the WiFi TCP/IP Receive block.
Apply the swapbytes function in a MATLAB Function block, and place the block immediately after the WiFi TCP/IP Receive block.

For more information, see Blocking Mode and Non-Blocking Mode.

Status — Requested data received at given time step
`1` | `0`

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 1. Otherwise, it outputs 0, indicating that no new data is received.

For more information, see Blocking Mode and Non-Blocking Mode.

Data Types: int8

Parameters

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Main Tab

Connection mode — Set block as server or client
`Server` (default) | `Client`

Set the block as a 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 a Remote IP address and the Remote IP port on the TCP/IP server from which you want to receive the data. Before you deploy a model that includes a client WiFi TCP/IP Receive block, ensure that the server is up and running.

Local IP port — IP port on receiving host from which data is received
`25000` (default) | [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.

Dependencies

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

Remote IP address — Remote IP address of server from which data is received
`192.168.1.2` (default) | any valid IP address

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

Dependencies

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

Remote IP port — Remote IP port on server from which data is received
`25000` (default) | [1 to 65,535]

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

Data size (N) — Number of bytes in received data
`1` (default) | any positive integer

The number of bytes to receive at each time step.

The maximum number of bytes that can be received by this block at each time step is shown in the table.

Target Hardware	ESP8266	WiFi Shield	MKR1000
Maximum Number of Received Bytes	40	64	1400

Sample time — Interval at which block reads data from sending host
`0.1` (default) | `-1` | any 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. When the hardware is ESP8266, the minimum sample time allowed is 0.01 seconds. Otherwise, it is 0.000001 seconds (1 microsecond).

Advanced Tab

Wait until data received — Wait until requested data is available
off (default) | on

When you select this option, the read operation runs in Blocking Mode. The read operation is blocked while waiting for the requested data to be available. When waiting for the data, the Status port displays same values from the previous time step. When the data become available, the Data port outputs data bytes, and the Status port changes to 1.
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 option, the read operation runs in Non-Blocking Mode. When reading data, if data is not available, 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 0. In this mode, the block does not wait for the requested data to be available.

Timeout in seconds — Time to wait until the data is received
`0.1` (default) | (0, 2^32/1000]

Specify the amount of time that the block waits for the data during each time step. If timeout occurs, the read operation is aborted.

Note

When simulating a model in External mode, we recommend you to specify Timeout in seconds less than 3 seconds.

Dependencies

This parameter appears only when you select the Wait until data received parameter.

More About

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Blocking Mode

In blocking mode, the model blocks execution while it waits for the requested data to be available. This figure shows an example workflow with Data size (N) set to 4.

At time step 1, the block requests data and receives four data values. This matches the value of Data size (N). The value at the Status port changes to 1, indicating that new data is available. The Data port at this point outputs the newly received data values. The block resets the buffer size to 0.
At time step 2, the block requests data again but receives only three data values. The execution pauses until the block receives the fourth data value or until the timeout value elapses. Then execution resumes.
At time step 3, the block requests data and receives five data values. The Data port outputs the first four data values, and the remaining data value is used in the next receipt cycle. The value at the Status port changes to 1.

Non-Blocking Mode

In non-blocking mode, the model runs continuously. This figure shows an example workflow with Data size (N) set to 4.

At time step 1, the block requests data and receives four values. The block fulfills the request and changes the Status port value to 1, indicating that new data is available. The Data port at this point outputs the newly received data values. The block resets the buffer size to 0.
At time step 2, the block requests data again, but receives only three values. The block outputs three data values. The block sets the Status port value to 0, indicating that there is no new data. All the values at the Data port become 0. During this phase, the execution does not stop.
At time step 3, the block receives five values. The Data port outputs the first four data values in the order received and changes the Status port value to 1. The remaining data value is used in the next receipt cycle.

Version History

Introduced in R2014a

WiFi TCP/IP Receive