8.4 Display Edge Switching Thresholds

Text Objects that are attached to edges can be made to show the high and low voltage thresholds, and the edge time transition points. The signal’s analog properties determine the placement of the marking lines and the values of the properties.

To display the switching thresholds or edge transition times:

•Add a text object that is attached to the edge (see Section 6.1 Text), then double click on the text to open the Edit Text dialog. Select the type of display that you want from the Signal Edge Thresholds section. If this section is greyed out, then it means that the text object is not attached to an edge.

edgethresholds_dialog

•Checking the High Voltage Threshold box creates a tick line at the high voltage level indicated in the Analog Properties dialog and displays the voltage. It is similar for the other two settings.

Edgethresholds

•To adjust the analog settings, double click on the signal name and press the Analog Prop button to open the Analog Properties dialog.

•The placement of the marking lines is set using the High Switch Threshold and Low Switch Threshold settings. By default these are set at 90% and 10%.

•The value of the display is set using the Logic High Voltage and Logic Low Voltage settings. For example a 90% of 5v is 4.5v and that will be the default value of a text object displaying a high voltage threshold.

analogprops