NNG Receive

R2026b

Receive data through nanomsg next gen (NNG) using publish/subscribe protocol

Since R2023a

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NNG Receive block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Raspberry Pi Blockset / Communication

Description

Use the NNG Receive block to receive data from the publisher for the specified uniform resource locator (URL). The block uses a publish/subscribe protocol for all inter process communications. In the publish/subscribe protocol, each publisher that wants to send data publishes them on a certain URL while, each subscriber that wants to receive data subscribes to the same URL.

Note

To generate C/C++ code for this block, you must have an Embedded Coder^® license.

Examples

Communicate Data Between Raspberry Pi and Sense HAT Using NNG Blocks

Use the NNG Send and NNG Receive blocks from Raspberry Pi® Blockset to establish communication between the Raspberry Pi hardware and Sense HAT using the nanomsg next generation (NNG) library.

• Open Model

Ports

Output

Data — Received data

[Nx1] array

The data received from the publisher, specified as a N-by-1 vector. N is the length of the message specified by the Data length (N) parameter.

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

Status — New message indicator

0 | 1

If the subscriber receives a new message since the last sample time, the Status port outputs 1. Otherwise, the port outputs 0.

Data Types: Boolean

Parameters

IPC name — Name of inter process communication

pubsub (default) | string

Enter the name of the inter process communication (IPC). This IPC name reflects in the URL.

URL — Service address to send and receive data

ipc:///tmp/pubsub.ipc (default) | string

A URL is a service address used by the publisher to identify rightful subscribers for delivering data. This URL is used by the publisher to receive data sent on the same URL. The IPC name reflects in the URL.

Note

You cannot edit this parameter.

Data type — Type of input data

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

Select the type of input data that the subscriber receives at each sample time.

Data length (N) — Length of input data

1 (default) | integer between 1 and 2^31

Enter the maximum length of data that the subscriber receives at each sample time.

Print diagnostic messages — Save subscriber response to log file

off (default) | on

Select this option to save the response from the subscriber to a log file each time the data is received by the subscribers. The name of the log file is the Simulink^® model name followed by .log.

Sample time — Frequency to check for data from server

-1 (default) | any positive integer

Enter how often the subscriber checks for new data from the publisher. When you specify the sample time as -1, the block inherits its sample time based on the context of the block within the Simulink model.

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"raspberrypiCommlib/NNG Receive"

Example: add_block("raspberrypiCommlib/NNG Receive","myModel/myBlock",MakeNameUnique="on")

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using Simulink® Coder™.

To generate C/C++ code for this block, you must have an Embedded Coder license. For more information on selecting the right product stack according to your development goals, see Product Stack for Raspberry Pi Blockset.

Version History

Introduced in R2023a