Configuring the Digital IO Module

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Modified by Admin on Sep 13, 2017

The Digital I/O Module can be configured after placement on the schematic sheet using the Digital I/O Configuration dialog (Figure 1). To access this dialog, simply right-click over the symbol for the device and choose the Configure command from the context menu that appears. Alternatively, click on the Configure button available in the Component Properties dialog for the device.

Figure 1. Configuration dialog for the DIGITAL_IO instrument.

Use the dialog to configure the device as required. The input and output signals are separate. You can define any number of signals for input or output, and the number of signals for each can differ. The following section takes a closer look at signal configuration.

Configuring Signals

Configuration of an input or output signal consists of defining the name and width of the signal, as well as the graphical representation for that signal on the device's instrument panel. Each signal will have the following associated fields in the dialog, with which to configure it:

Name – this is the name of the signal, as it will appear on the schematic symbol and the instrument panel. Click on this field to edit the default signal name and replace it with a more meaningful name, in context with the area of the circuit being monitored/controlled. Set the width of the signal – in terms of bits – as required. Although the width specified can be any number of bits, this will typically be kept to 8, 16 or 32 bits.

Style – this is the graphical display style used to represent the input signal (LEDs, Numeric, LED Digits, or Bar) or output signal (LEDs, Numeric, LED Digits, or Slider) on the instrument panel. For more detailed information on each style, see Graphical Display Styles.

Color – the color to use for the chosen graphical display style. This field is not applicable to the Numeric or Slider display styles.

Radix – the number system to use for the chosen graphical display style. This field is not applicable to the LEDs, Bar, or Slider display styles.

Preview – shows an example image of how the chosen display style will look when viewed on the instrument panel.

Initial Value – applicable to an output only, this field allows you to control the initial value for an output when the program is first downloaded to the FPGA and the instrument starts running.

In addition, the following four buttons are associated with both the Input Signals and Output Signals regions of the dialog:

Add and Remove – add a new signal to the device or remove an existing one

Move Up and Move Down – use these buttons to control the order of the signals, as they appear on the schematic symbol.

Graphical Display Styles

The following tables illustrate the various display combinations available for each supported display style. In each case, an example of the resulting display on the instrument panel is shown. For consistency, each display on the instrument panel is set to show the 16-bit value 1010_0000_1111_0101.

Table 1. Display combinations for style LEDs.