Cadence PCB Best Practices

Working with Real-Time DFA Analysis

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Working with Design Partitions Design Partitioning October 2019 17 Product Version 17.4-2019 © 1999-2019 All Rights Reserved. group (window) selection of one or more guideports. There is a restriction that all guideports in a group selection must be located on the same partition boundary segment. If a selected guideport is part of a diff pair, then the associated diff pair mate guideport is added to the selection, provided that the Auto-Select Diff Pair Mate option is enabled. Figure 1-6 Guideports Guideports snap to the partition boundary when you move or spread them. These actions also consider the current settings of the spacing criteria options. The master designer can specify the spacing criteria to be the Default Grid, the Minimum Line-to-Line Spacing by Net, or a user-defined value. The master designer can also choose to ignore all spacing rules. When a two or more guideports are in the selection set, the geometric midpoint of the selection extents is used as the anchor and the seed point for implementing the selected spacing requirement. Working outward in both directions from this anchor point, the algorithm adjusts the locations of the guideports according to the spacing criteria until each is satisfied, or the end of the partition boundary segment is reached. Tip When creating boundaries or adding guideports, set the grid to a multiple of the routing grid. Interfacing at the Boundaries – The process of routing connections to the boundaries requires some discipline and communication across the team. There may be times when two designers attempt to route signals to a shared boundary only to find out they are on separate layers. The layer set functionality can help minimize the chance of layer misalignment. A layer set can be made up of 1 to layers and can be applied to nets, differential pairs or buses. While this solution sounds simple if the set consists of just one routing layer, when working with a set composed of two layers, the designers would have to agree on what layers are used for directional routing. For example, if routing in the y direction, use layer 4; if routing

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