JPH04290170A - Automatic wiring system using labeling - Google Patents

Abstract

PURPOSE:To reduce mutual interference between wiring pattern by increasing the weight of each cell toward existent wiring patterns when labeling is performed from a start point cell to a destination point cell on a wiring plane. CONSTITUTION:The start point cell S and destination point cell T are determined on the wiring plane 101. Weight 'b' is given to an area 105 near a cell 104 which is already wired and 'a' is given to other cells so that a<b. For example, a=1 and b=2. A cell A is given a label value '1' in a 1st step and a cell B is given a label value '3' obtained by adding the weight '2' of the cell B in a next step. Label values from the cells B and C are sent to a cell D in a 3rd step and a label value '4' is sent from the cell C which is smaller in value. The labeling is performed up to the cell T. The cells are traced from the cell T to the cell S so that the label value decreases, thus obtaining a wiring path.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to an automatic wiring method using labeling, and in particular, the wiring plane of a printed circuit board or LSI chip to be routed is divided into a grid pattern, and the starting point cells on this wiring plane are By sequentially labeling from the (lattice) to the destination cell, and then following the cells whose label value decreases from the destination cell to the starting point cell based on the labeling results,
This paper relates to an automatic wiring method that finds a wiring route between both cells.

With the recent progress in integrated circuit technology, printed circuit boards, LSIs, etc. have become more densely packed and their operating speeds have improved.
It is becoming increasingly necessary to suppress noise and crosstalk between channels. Furthermore, as signal frequencies become higher, delays in wiring patterns cannot be ignored, and it has become necessary to specify the wiring length when designing the wiring. The present invention
The present invention relates to an automatic wiring method to meet such demands.

[Conventional technology]

FIGS. 3 to 4 illustrate the conventional maze method, which is a method of sequentially labeling from a starting point cell to a destination cell using a computer and finding a wiring route between both cells based on the results. Explain using. As shown in the figure, the wiring plane of a printed circuit board, LSI, etc. is divided into grid-like cells, S and T are cells corresponding to terminal pairs to be automatically wired, S is a starting point cell, and T is a cell. A destination cell is shown, and 104 is a wired cell in which a wiring pattern has already been set.

[0004] At first, the only active cell that has the ability to transmit label values to adjacent cells and perform labeling is the point S, and from the point S, the four cells located above, below, left and right of this cell are active.
labeling two neighboring cells, i.e. the label value of point S itself (e.g. "0") and the weight of each neighboring cell (e.g. "1").
'') is added to each adjacent cell.

In the following description (including the description of FIGS. 1 and 2), all labeling below the starting point cell S is omitted. Moreover, labeling is not performed on wired cells 104 for which wiring patterns have already been set.

[0006] In the next second step, as shown in FIG. 3(a), the cells that were labeled in the first step (the numbers surrounded by circles) become active cells, and these Labeling is performed in the direction of the arrow from the active cell, and new label values are assigned to adjacent cells located above, below, left and right of the active cell.

[0007] Labeling is performed in the same procedure below.
The label state when a label value is assigned to the destination cell T is as shown in FIG. 3(c). Subsequently, by sequentially tracing cells with decreasing label values from the destination cell T to the starting point cell S, the wiring route between both cells is determined, for example, as shown by a solid line.

[0008]

[Problem to be Solved by the Invention] According to such a maze method, the shortest wiring route connecting the starting point cell S and the destination point cell T is set, but in the process of setting, the existing wiring pattern and Since no consideration is given to the positional relationship between cells, in other words, the weight of each cell is set to the same value ("1" in the explanation of FIGS. 3 and 4), the portion adjacent to this existing wiring pattern becomes longer and causes noise. There was a problem that crosstalk increased.

In addition, in order to shorten this adjacent portion, the wiring route determined by the maze method is manually corrected, as shown in FIG. 4, for example, but this change increases the wiring process. There are problems in that the required processing time becomes longer, and as the wiring pattern becomes denser, it becomes difficult to make such local changes.

Therefore, in the present invention, the weight added during labeling is set to be different depending on whether the cell to which a new label value is assigned is located near the existing wiring pattern or not. By setting the former to a larger value than the latter in advance, the wiring route set based on the labeling results will be separated by a predetermined length from the existing wiring pattern, making it easier to perform subsequent manual operations. The purpose of this invention is to reduce mutual interference with existing wiring patterns without making any modifications.

[0011]

[Means for Solving the Problems] The present invention sets the weight of each cell used when performing labeling from a starting point cell to a destination cell on a grid-like wiring plane to be close to an existing wiring pattern. A certain cell is set in advance so that it is larger than a cell further away from the wiring pattern.

FIG. 1 is a diagram explaining the principle of the present invention. In the figure, reference numeral 101 denotes a wiring plane, which corresponds to the planar shape of a printed circuit board or an LSI chip to be wired, and is made up of a plurality of lattice-shaped cells. Reference numeral 102 denotes a starting point cell S, which corresponds to one of a pair of terminals targeted for automatic wiring processing. Note that the label value of this cell is normally set to "0". 103 is the destination point cell T
Yes, and corresponds to the other terminal pair that is subject to automatic wiring processing. Reference numeral 104 indicates a wired cell, which is an area corresponding to an existing wiring pattern and cannot be used as a new wiring area. Reference numeral 105 is an area near the wired cells, and the weight value of the cells in this area is set in advance by "b
", and this value "b" is set to satisfy the relationship "a<b" with respect to the weight value "a" of the cell outside the area.

Note that the range of region 105 is not limited to cells adjacent to the existing wiring pattern, but may include cells that are a plurality of cells away from this wiring pattern. In addition, each of the addition values a and b may vary depending on the cell within the range of the condition that cells near the existing wiring pattern are made larger than cells far from the existing wiring pattern. You can also set it to a larger size.

FIG. 1(a) shows the label state when labeling from cell S reaches the third step when "a=1, b=2" is set, and the arrow indicates the labeling state. The numbers indicate the direction, the numbers indicate the label values of each cell, and the encircled numbers indicate the label values assigned in the second step of labeling.

Here, cell A is given a label value of "1" in the first step, and cell B is given a label value of "1" and a weight of cell B of "b=2" in the second step. ” is added and the label value is “3”. And in cell D,
In the third step, respective label values are transmitted from cell B and cell C, and labeling is performed from cell C, which has the smaller value, and a label value of "4" is assigned.

Thereafter, labeling using this weight is performed sequentially up to the destination cell T, and the label state at the time the labeling is completed is as shown in FIG. 1(c). continue,
By sequentially tracing cells with decreasing label values from the destination cell T to the starting point cell S, a wiring route as shown, for example, can be obtained.

[0017]

[Operation] In this way, prior to labeling on a grid-like wiring plane, the weights of cells near the existing wiring pattern are given more weight than the weights of cells far from the existing wiring pattern. By setting a large value and making sure that the label value of the latter cell is always larger, cells near the existing wiring pattern are not used as wiring routes, and a predetermined route is taken from this wiring pattern. Routes that are separated by the same length are determined using automatic wiring processing using a computer, without any manual correction work.

[0018]

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. The figure is an explanatory diagram showing a flow when performing automatic wiring between multiple nets (same potential points). That is, 1) Input data used for automatic wiring between multiple nets, such as a net list, position data of existing wiring patterns, and design rules, and proceed to the next step. (2) Set the weights a and b of each cell in the area far from the wired cell and the area close to the wired cell, respectively, and proceed to the next step. Note that the values of a and b are set so that "a<b". ■Specify the unwired nets and proceed to the next step. (2) Execute labeling from the starting point cell to the destination point cell on the wiring plane corresponding to each of the specified nets to find the wiring route between both cells (see FIG. 1), and proceed to the next step. ■Determine whether wiring routes for all nets have been determined. If YES, proceed to the next step; if NO, return to step ■. ■
Determine whether the determined wiring route has the specified wiring length, and if ``YES'', proceed to the next step and select ``
If NO, return to step ■. ■Output the determined wiring route. Through these steps, a wiring route with a predetermined wiring length is determined.

[0019] Here, since the positional relationships of the wiring routes in the net portion with dense wiring targets depend on each other, the determined wiring route may deviate from the specified wiring length. In this case, the weight of each cell is updated by executing the process of step (2) following step (2), and the automatic wiring process is executed again using the updated weight.

[0020]

[Effects of the Invention] According to the present invention, the weight of each cell used in labeling from the starting point cell to the destination point cell on the wiring plane is set in consideration of the distance from the existing wiring pattern. Even without performing manual correction processing after automatic wiring processing, it is possible to reduce the rate at which wiring routes become too close to each other and noise, crosstalk, etc. occur between them.

[0021] Furthermore, if the wiring route once determined is outside the specified wiring length, the weight of each cell is reset and then the automatic wiring process is repeated, so that the final It is possible to increase the proportion of wiring routes that have a specified wiring length.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention.

FIG. 2 is an explanatory diagram showing a flow when automatically wiring between multiple nets (same potential points) according to the present invention.

FIG. 3 is an explanatory diagram showing a conventional method of determining a wiring route (maze method).

FIG. 4 is an explanatory diagram showing a wiring route after a conventional manual correction work has been performed.

[Explanation of symbols]

101... Wiring plane 102... Starting point cell 103... Destination point cell 104... Wired cell (existing wiring pattern) 105
...adjacent cell

Claims (2)

[Claims] 1. A wiring plane of a printed circuit board, an LSI chip, etc. is divided into a grid pattern, and the label value of any cell on this wiring plane is transmitted to adjacent cells located above, below, to the left, and to the right.
A new label value obtained by adding the weight of each adjacent cell to this label value is applied to each adjacent cell. Labeling is performed sequentially from the starting point cell, and based on the result of this labeling, the destination cell is transferred to the starting point cell. In an automatic wiring method that finds a wiring route between two cells by sequentially tracing cells with decreasing label values, the weight value is set to a value that is different from a wired cell where an existing wiring pattern exists. Set in advance so that the cells near this wired cell are larger than the cells in the wired cell.
An automatic wiring method using labeling, characterized in that the wiring route determined based on the labeling result is separated from the existing wiring pattern by a predetermined number of cells. [Claim 2] If the wiring length of the wiring route determined based on the labeling result is not within a predetermined range, the weight of each cell is reset and then the automatic wiring process is repeated. An automatic wiring system using labeling according to claim 1.