JP2721712B2 - Automatic wiring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to an automatic wiring method for an LSI or a printed circuit board which forms a wiring pattern on a wiring surface. The purpose is to automatically search for a high-density wiring pattern. A route search for a wiring pattern is performed, a wiring cell group closest to an existing wiring pattern is automatically selected, and these wiring cell groups are connected to each other, so that high-density wiring with a high density between wiring patterns and high wiring efficiency are performed. Automatically search for excellent wiring patterns.

[Industrial Application Field] The present invention relates to an automatic wiring method for an LSI or a printed circuit board.

In recent years, with the increasing mounting density of LSIs and printed circuit boards, it has become necessary to take a lot of time to form wiring patterns that can efficiently connect between mounted components and the like.
There is a demand for a method for automatically searching for a wiring pattern with high density and excellent wiring efficiency.

In particular, in the case of a printed circuit board or LSI that requires a wiring pattern to be formed on a specific wiring surface, it is necessary to efficiently form the wiring pattern on one surface so that the wiring pattern does not cross. As a result, the wiring patterns automatically searched for have low density and a long distance connecting the destination points. The case is increasing.

[Prior Art] Conventionally, an automatic wiring method using a maze method is known. First, according to this conventional method, as shown in FIG. 4, for example, the wiring surface is divided into small wiring cell groups arranged in a matrix in the vertical and horizontal directions (indicated by dotted lines in the drawing), and these wiring cells are divided. Are appropriately connected to determine a wiring pattern. Further, as shown, the terminals P _s1 and P _e1 , P _s2
When searching for wiring patterns to connect P _e2 and P _s3 and P _e3 , respectively, as shown in wiring patterns A, B, and C, the length of each is automatically set to the shortest and the number of bends to the minimum. Set.

[Problems to be Solved by the Invention] However, in such a conventional automatic wiring method, individual wiring patterns can be determined so as to have the shortest length, but are individually set to the last. Therefore, since it is not determined in consideration of the mutual relationship with each other adjacent wiring pattern, as shown in FIG. 4, the bent portion (for example, the wiring pattern A or C) travels outside. There is a problem that a rectangular empty portion is generated between the destination points, or a portion that travels outward moves a formation position of a wiring pattern adjacent to the next one, thereby lowering wiring density.

The present invention has been made in view of such a problem, and when searching for an optimum wiring pattern adjacent to a certain existing wiring pattern, the distance between the wiring patterns is increased to achieve high density and excellent wiring efficiency. It is an object of the present invention to provide an automatic wiring method in an automatic wiring system capable of automatically searching for a wiring pattern that has been used.

[Means for Solving the Problems] FIG. 1 is an explanatory view of the principle of the present invention.

First, the present invention provides an automatic wiring method for searching for a wiring pattern to be formed on a specific wiring surface of an LSI or a printed circuit board. The present invention is directed to an automatic wiring method in an automatic wiring system capable of automatically searching for a dense wiring pattern with high density and excellent wiring efficiency.

As shown in FIG. 1, a specific wiring surface of an LSI or a printed circuit board is divided into small wiring cell groups arranged in a matrix in a vertical direction and a horizontal direction (indicated by dotted lines in the figure), and these wiring cells are divided. Are appropriately connected to determine a wiring pattern.
Furthermore, existing wiring pattern L1 is set for connecting a wiring cell P _ts and P _te be connected to the terminal or the like of the mounted components, the wiring with connecting between the desired wiring cell P _s and P _e Assuming that a new wiring pattern adjacent to the pattern L1 is to be searched, a specific value S is set for the search start point, and a specific value S is set for the wiring cell adjacent to the existing wiring pattern L1. A value obtained by sequentially adding a constant a from the closest order is set, and a value obtained by adding a constant b (where b> a) is sequentially added to a wiring cell located at a position distant from the wiring pattern L1. Is set to the search end point, and a new wiring pattern is determined by connecting the wiring cells in which small values from the search start point to the search end point are set in order.

Further, explaining the principle in detail, as shown in FIG. 1 (A), the search starting point the wiring cell from P _s to search end point _{P e C (i, j-} 1), C (i, j ) To C (i + 5, j), C (i, j
+1) ~C (i + 5, j + 1) is set as such, a predetermined initial value S with respect to the search start point P _s. Furthermore,
An addition value to be added to a wiring cell adjacent to a wiring cell constituting the existing wiring pattern L1 is set to a, and an addition value to a wiring cell distant from the wiring cell is set to b> a.

Next, a value (hereinafter, referred to as a label value) for each wiring cell is sequentially calculated according to the above conditions.

That is, first closest to the search starting point P _s wiring cell C (i,
j) is apart from the existing wiring pattern, so S + b is used as the label value.

Next, the wiring cell C (i + 1, j) vertically adjacent to the wiring cell C (i, j) is adjacent to the existing wiring pattern, and a value S + b + a obtained by further adding a is used as the label value.
The wiring cell C (i, j) adjacent to the wiring cell C (i, j) in the horizontal direction
Since (i, j + 1) is not adjacent to the existing wiring pattern, b
The value S + b + b = S + 2b obtained by adding the above is defined as the label value.

A label value as shown in FIG. 1B is set by performing the same arithmetic processing on other wiring cells.

Furthermore, the vector order of performing the operation based on the search starting point P _s represents a vector as shown by an arrow in the figure, a path from the search start point P _s to search starting point P _e in ascending order of the label values To form a wiring pattern.

Then, the same processing as described above is performed using the new wiring pattern thus determined as the next existing wiring pattern, and a new wiring pattern is searched for, and this is repeated until the processing is completed for all wiring surfaces. Thereby, a desired wiring pattern group is formed.

[Operation] According to the processing method of the present invention, the addition value is b>
because it is set in the relationship of a, label value as the wiring cell close to the existing wiring pattern becomes a small value, yet the label value in sequential order to search the end point P _e from the search start point P _s is going to increase since the fact, by connecting the path from the search start point P _s to search starting point P _e along a vector in ascending order of the label values, the parallel wiring pattern approaching the existing wiring pattern is formed Therefore, unused wiring cells as in the related art can be significantly reduced. As a result, the utilization efficiency of the wiring cells can be increased, and the wiring ratio can be improved.

Further, an optimum wiring pattern group may be selected from a wiring pattern group obtained by repeatedly changing the added values a and b as appropriate.

[Embodiment] FIG. 2 is an explanatory view of an embodiment of the present invention, and shows processing when CAD or the like is applied. In addition, as shown in FIG. 2 (A), existing wiring patterns for connecting specific wiring cells _Pts and _Pte.
L1 is present, the initial label value of the search starting point P _s S = 0,
A description will be given of a case where the addition values a = 1 and b = 2 are set. Further, to i + 5 rows and j-1 to not i wiring cell group in the rectangular area surrounded by the search starting point P _s and the search end point P _e shall be indicated by the j + 1 column.

Upon activation of the automatic wiring system, processing is performed according to the flow shown in FIG. First, in a routine 110, coordinate data of an existing wiring pattern, coordinate data of a search end point of a search start point, and the like (hereinafter referred to as a netlist) are stored in a storage area, and the initial label value S is set to zero in the search start point. I do.

Next, in the routine 120, the added values a = 1, b = 2
Set.

In the routine 130, a net to be searched for a new wiring pattern is selected.

Then, in the routine 140, selects a line cell for connecting the search start point P _s and the search end point P _e of the net selection. In other words routine 140, first, the label values for neighboring wiring patterns of the search start point P _s C (i, j)
When computing the so not adjacent to existing wiring patterns L1, S + b = 2, and the vector direction indicated by the arrow a direction of the point P _s. Next, when the label value C (i, j + 1) of the array cell located at the i row j + 1 column is calculated, the label value C (i, j) is not adjacent to the existing wiring pattern L1.
The value C (i obtained by adding b to j), j) + b = 4 , and the vector direction indicated by the arrow a direction of the point P _s. In the same manner, the label values for the wiring cells in each matrix are calculated to set the label values indicated by circles in FIG. 2 (A) and the vectors indicated by arrows. By connecting the wiring cell in order according to a vector value of small value and from the search starting point P _s along the direction indicated by the vector between the search starting point P _s and the search end point P _e, FIG. 2 (B ), A new wiring pattern L2 as shown in FIG.

Next, in the routine 150, it is determined whether or not the processing of all nets has been completed. If the processing has been completed, the processing shifts to the routine 160 to output wiring pattern path data, and a series of processing is completed.

On the other hand, if the processing has not been completed in the routine 150, it is determined whether or not the processing for all the nets has been completed in the routine 170. If the processing has not been completed, the processing shifts to the routine 130 to process the next net.

Further, when the processing of the wiring patterns for all the nets is completed in the routine 170, the processing shifts to the routine 120, where the additional values a and b are set, and the processing is repeated again.

As a result, a plurality of types of wiring patterns that are generated by changing the addition conditions a and b in the routine 120 and that are generated by the difference in the setting conditions are generated.

Then, a designer or the like can select an optimum one from these plural types of wiring patterns.

According to this embodiment, since a parallel wiring pattern approaching an existing wiring pattern determined prior to a wiring pattern to be searched is searched, a wiring pattern with high density can be formed.

Further, in the prior art, a pattern L3 as shown by a dotted line in FIG. 2 (B) is searched, but according to this embodiment, the pattern of L2 is formed, so that the next wiring pattern is formed. The obtained wiring cell group (the wiring cell group in a region surrounded by a circle in the figure) can be secured, and the wiring rate can be improved.

By setting the added values a and b in a relationship of a <B and appropriately changing the value, another wiring pattern group can be searched. An optimum wiring pattern group is selected from a plurality of wiring pattern groups. can do.

[Effects of the Invention] As described above, according to the automatic wiring method of the present invention, the paths of a plurality of wiring patterns are determined to be close to each other, so that the wiring cells are effectively used and the wiring ratio is improved. This leads to effects such as a significant reduction in the number of design steps for LSI and printed circuit boards.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the principle of the present invention; FIGS. 2 and 3 are explanatory views of the processing procedure of the embodiment; FIG. 4 is an explanatory view of a conventional method. Reference numerals, L1, l2: wiring patterns P _ts, P _s: search starting point P _te, P _e: search end point

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideki Miwatari 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Yue Oki 1015 Kamedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited (56) References, edited by Takashi Sugiyama, “Practical ASIC Technology,” Industrial Research Committee (S62-4-24) P.P. 89−90

Claims (1)

(57) [Claims] A wiring surface is divided into small wiring cell groups arranged in a matrix in a vertical direction and a horizontal direction, and a new wiring pattern (L2) adjacent to an existing wiring pattern (L1) is connected to these wiring patterns. In an automatic wiring method that is determined by appropriately connecting cells, a specific value S is set for a search start point (Ps) of the new wiring pattern, and a specific value S is set for a wiring cell adjacent to an existing wiring pattern. Constant a from the closest to the search start point
Are sequentially added, and a constant b is sequentially set for a wiring cell located at a position distant from the existing wiring pattern.
(However, b> a) is set, the value is set, the search is performed to the search end point (Pe), and the connection from the search start point to the search end point is set in the order of the wiring cell in which the small value is set. An automatic wiring method characterized in that a new wiring pattern (L2) is determined by the above method.