External mode

Communication interface

Use the ‘serial’ option to run your model in the External mode with serial communication.

When running a model in External mode over serial, Simulink® generates error if the Hardware Serial Port parameter is set to Serial 0. The error is generated because the External mode uses serial port 0 to communicate with the Arduino board by default. Browse to WiFi properties, and ensure that the Hardware Serial Port parameter is set to a port other than Serial 0.

Warning

External mode over XCP on WiFi on Simulink models having more than 3 multirate systems result in a connection error.

Settings

Default: Serial — For AVR-based boardsXCP on Serial — For ARM-based boards

  • Serial

  • TCP/IP

  • WiFi

  • XCP on Serial

  • XCP on TCP/IP

  • XCP on WiFi

Logging buffer size (in bytes)

Specify the number of bytes to preallocate for the buffer in the hardware during Universal Measurement and Calibration Protocol (XCP)-based External mode simulation. Specify Logging buffer size (in bytes) to a value large enough to accommodate the logged signals.

When specifying the buffer size, ensure that:

  • The maximum value of this parameter does not exceed the available Arduino® memory, which the Simulink Real-Time™ also uses to store other items. For example, in addition to signal logging data, the software also uses the target computer memory for the Simulink Real-Time kernel, real-time application, and scopes.

    Assume that your model has six data items (time, two states, two outputs, and task execution time). If you enter a buffer size of 100000, the target object property tg.MaxLogSamples is calculated as floor(100000 / 6) = 16666. After the buffer saves 16666 sample points, it wraps and further samples overwrite the older ones.

  • You enter a logging buffer size larger than the available RAM on Arduino. When you download and initialize the real-time application, the hardware displays a message, ERROR: allocation of logging memory failed. To avoid this error, either install more RAM or reduce the buffer size for logging, and then restart the hardware. To calculate the maximum buffer size available for your real-time application logs, divide the amount of available RAM by sizeof(double), or 8. Specify that value in the Logging buffer size (in bytes) value.

Settings

Default: 1000000

Verbose

Select this check box to view the External Mode execution progress and updates in the Diagnostic Viewer or in the MATLAB® Command Window. This parameter appears when you select TCP/IP or WiFi for Communication interface.