DAC (digital to analogue conversion) monitoring issue

Hello Mathworks community, I need to monitor some signals from a Simulink file in external mode on an oscilloscope using the DAC block from the Launchpad F28379 library. I attempted to connect it; however, when I begin generating code with the DAC connected, the external mode is terminated.

I was wondering if any one could help out with this.

I have attached a screenshot of the component

Regards, Mohamed

Answer 1

[Sivapriya Srinivasan]

Hello,

Here are some ways to try

1.The oscillator frequency must match the Launchpad’s external oscillator frequency. While the F28379D has an internal crystal that oscillates at 20MHz, the LaunchPad also has an external oscillator that runs at 10MHz. Simulink's default value is 20MHz. This setting is appropriate when working with the F28379D alone. However, this frequency value can cause problems when using external mode on a LaunchPad.

Please go to Hardware Implementation -> Device details -> Clocking and change the value of "Oscillator clock (OSCCLK) frequency in MHz" from 20 to 10.

2.Make sure the connection between the Launchpad F28379 board and the host computer is proper and the board is detected by the host computer. You should verify that your serial over USB is configured properly and that you are using the right COM port.

The following page will help you:

http://processors.wiki.ti.com/index.php/Using_the_serial_adapter_of_XDS100

3.Check if there are any conflicts between your DAC connection and any other devices or connections. Disconnect any other devices or connections and try again.

4.Check if the Launchpad F28379 library has any compatibility issues with your Simulink version. Make sure that the library is compatible with the Simulink version you are using.

5.Make sure you're using the correct versions of the TI C2000 support package and the Launchpad F28379 library. Make sure to update your support package to the latest version by following the download link on this page: Embedded Coder Support Package for Texas Instruments C2000 Processors.Support Packages versions 16.2.5 and above fix this problem.

6.Try using a different method to monitor the signals, such as using the UART communication block. The only other known possible case where you would face this problem is when the COM port is used by another application (like a hyper terminal) while you run External mode. Make sure that the COM port is free to use by MATLAB prior to launching External mode simulation.

7.Increase the buffer size of the external interface to allow for the extra traffic that the DAC block generates.

I hope one of these solutions will help you overcome the issue you're facing! Let me know if you have any further questions or concerns.