Use Telnet to interface with the UART

All output is now directed to the model’s UART serial port.

To see this output, we are going to use a Telnet client to connect to the UART. We will use Arm Development Studio to help here, because it automatically starts the Telnet client and connects it to the model.

Note: If you want to start a Telnet client and connect to the model manually, you will need to use port 5000 instead of the default port 23. Timing the connection can be difficult, because you must start the client just before the server in the model starts listening.

To interface with the UART using Telnet:

  1. Import your executable into Arm Development Studio.

    Click File > Open Projects from File System…


  2. Click Directory in the Import Projects from File System or Archive dialog to select the folder containing your executable, as this screenshot shows:

  3. Click Finish. Your project files should appear in the Project Explorer tab.

  4. Right-click the __image.axf file, then select Debug As > Debug Configurations to display the Debug Configuration dialog box. You can see the dialog box in the following screenshot:

  5. Select Generic Arm C/C++ Application, then click the New launch configuration button to create a new debug configuration.

  6. In the Name field, give your debug configuration a name, for example FVP_Base_Cortex-A76x1.

  7. On the Connection tab select ARM FVP (Installed with Arm DS) > Base_A76x1 > Bare Metal Debug > Cortex-A76, as this screenshot shows:

  8. On the Files tab, click File System and select your __image.axf file, as this screenshot shows:

  9. On the Debugger tab, select Debug from symbol: main as this screenshot shows:

  10. Click Apply, then Close.

  11. On the Debug Control tab, double-click your debug configuration to start the model and run your application. Execution pauses on entry to main(), and you should see the Fast Models window appear, as this screenshot shows:

  12. Click the Continue toolbar button to continue execution.

    Arm Development Studio automatically starts the Telnet client and connects to the model.

    The application output, “hello world”, will appear in the Telnet client window after it has been sent over the UART serial interface, as this screenshot shows:

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