Differential Pair Spacing Check

For tracks and vias that you select on the canvas, and which are part of a differential pair, the Differential Pair Spacing Check command displays any track-to-track spacing errors for track segments. This is helpful when reporting errors related to use of pin pairs for Impedance Balanced Routing (IBR).

These are listed in the Spacing Errors (Pin Pair) dialog for the two pin pairs in the relevant track segment. For each track in a selected differential pair, the entire track is checked. For each track segment in the selection, the actual track-to-track spacing is compared to the value specified in the rule stack in Rule Editor. The hierarchy of rules is checked in the following order.

1. Pin pair
2. Differential pair
3. The default value that is set for the pin pair in Rule Editor.

Toggle on this command by selecting Report > Design Rule Checking > Differential Pair Spacing Check on the ribbon in eCADSTAR PCB Editor. On the canvas, select a track or via in a differential pair. The Spacing Errors (Pin Pair) dialog is automatically displayed. Alternatively, select an item on the canvas and then toggle on this command.

• Select Exit on the assist menu to toggle off this command.
• If you select a different item on the canvas, then the contents of the dialog are immediately updated.

 

 

For the selected differential pair, any errors are listed in the Spacing Errors (Pin Pair) dialog, described below. If there are no errors, then a dialog is displayed to confirm this. This displays the names of the relevant differential pairs.

Item		Description
Spacing errors table		Lists any track-to-track spacing violations for the two pin pairs in each track segment. Errors are shown if the actual spacing between the tracks is shorter or longer than the spacing specified in the differential pair rule stack. If you select a row in the table, then the canvas is zoomed to show the selection. The current layer is changed to the layer of the selected track. If multiple rows are selected, then it is changed to the most common layer. Select multiple rows using the CTRL or Shift keys, or by dragging the cursor. Change the order of the columns in the this dialog by dragging them. If you click a column, then the displayed data is sorted by that column. Click the column again to reverse the sort order. The formatting which you set is reflected in the data that is saved or printed from this dialog.  If you change the size or position of this dialog, or the width of a column, then these changes are saved automatically when the dialog is closed. However, the column that is used for sorting and the sort order are not saved. Note The following limitations should be considered. The errors displayed in the dialog are not updated automatically when routing or relevant constraints are changed. If you change the units or decimal places in the in Canvas View Settings dialog, then the new values are used when the dialog is next updated. For tracks that are not in a trunk, or tracks in a layer exchange: errors are not shown if the spacing between the tracks is wider than the specified rule.
	Differential Pair	The name of the differential pair. By default, the table is sorted by this value.
	Pin Pair Pair	The two pin pairs are displayed for the relevant track segment. They are separated using the ",'" character. For each pin pair, the order of the pin names may be opposite to the value in Constraint Browser. To display the pin names as they are listed in Constraint Browser, point the cursor at a value in this column.
	Track To Track Spacing	The track-to-track spacing is shown that is specified for the relevant pin pair. The units and decimal places are used that are currently set in eCADSTAR PCB Editor.
	Actual Track To Track Spacing	The track-to-track spacing is shown for the relevant pin pair on the canvas, rather than the value specified in Rule Editor. The units and decimal places are used that are currently set in eCADSTAR PCB Editor.
	Layer	The number of the Conductor layer that is associated with the pin pair.
	Track	The coordinates of the start and end points of the relevant track segment. They are separated using the "->" characters. The units and decimal places are used that are currently set in eCADSTAR PCB Editor.
Save As		Saves the contents of the dialog to a location that you specify. You can select from the following formats. .txt .rep .log .htm .html If you change the order of the columns by dragging them, or the order of the values in a column by clicking the column header, then these changes are reflected in the saved data.
Print		Prints the contents of the dialog. If you change the order of the columns by dragging them, or the order of the values in a column by clicking the column header, then these changes are reflected in the data that is printed.
Close		Closes the Spacing Errors (Pin Pair) dialog. Alternatively, press the Esc key. It is also closed if you switch or close the design. If you change the size or position of this dialog, or the width of a column in the table, these changes are saved automatically when it is closed.