JPH01292473A - Method for determining wiring route - Google Patents

Abstract

PURPOSE:To determine a wiring route between unconnected terminals by finding out positions capable of forming through-holes on a wired substrate and successively extracting through-hole formation enabled positions to be connected from both the ends of the unconnected terminals. CONSTITUTION:One-layer wiring routes 1 are horizontal wiring routes, two-layer wiring routes 2 are vertical wiring routes and through-holes for connecting the horizontal and vertical wirings are arranged. On the substrate, positions 8 (unused through-holes) capable of forming through-holes are found out, whether sccessive connection from unwired terminals 5, 6 to close unused through-holes is available or not is decided and through-holes to be connected are displayed on a display device. An operator determines a wiring route 9 between unconnected terminals from the displayed through-holes.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a wiring route determination method, and in particular, a method for displaying usable empty through holes and trunk routes over an existing wiring pattern, and This invention relates to a wiring route determination method for determining a new wiring route as an auxiliary means.

[Prior art] Wiring design for printed circuit boards, etc. is automated using automatic wiring programs that use heuristic methods, but as wiring becomes denser and more sophisticated, the probability of unconnected signals appearing has increased. Is high. As is well known, the method of determining a wiring route for an unconnected signal in an interactive CAD system according to the prior art is to display the wiring state in detail and manually search for a wiring route that connects the unconnected terminals.

In addition, as other prior art of this kind, for example,
A technique described in Japanese Patent No.-9560 and the like is known.

In this conventional technique, unused wiring terminals and unused wiring routes are displayed, and a new wiring route is determined by one person based on this display.

[Problem to be solved by the invention] In order to connect unconnected signals in high-density multilayer printed wiring boards, etc., relay holes (hereinafter referred to as "through holes") are essential for electrically connecting layers. . especially,
When connecting unconnected signals over long distances, deciding where to use the through hole is an important point in finding a path to connect unconnected signals.

The conventional technology described above is a route-based wiring method that uses existing wiring routes or unused routes, and the positions of through holes are determined by trial and error, resulting in a large number of man-hours for determining the wiring route. The problem is that there are

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and provide a method for determining wiring routes for printed wiring boards and the like.

An empty through hole is extracted from the existing wiring state and design rule information, a trunk route is determined from this empty through hole, the extracted empty through hole and the determined trunk route are displayed together on a CRT, and this display information is displayed. An object of the present invention is to provide a wiring route determining method that can reduce the number of work steps for determining a wiring route by determining the wiring route using the auxiliary means.

[Means for Solving the Problems] According to the present invention, the purpose is to extract unused through holes from existing wiring routes, wiring prohibition information, and design rule information;
Based on the existing wiring state around the unused through hole position, a threshold value is set that indicates the difficulty of generating a new route when the unused through hole is selected as a vacant through hole, and pruning is performed from this threshold value. By doing this, empty through holes are determined, and each determined empty through hole holds a cost value indicating the wiring difficulty level when that through hole is selected, and the main route is routed from this determined empty through hole. That is, the route between the start point of the unconnected signal and the empty through hole, between the empty through hole and the empty through hole, and between the empty through hole and the end point of the unconnected signal is determined, and the determined empty through hole and the main route are determined. This is achieved by displaying it on a display device. By using the displayed empty through holes and main route, the operator determines the wiring route between the unconnected signal terminals.

[A functioning cost through-hole is a connection point for a wiring route that can be used on both the front and back sides, and a collection of empty through-holes, for example, a continuous horizontal and vertical collection, represents a thin wiring density in an already routed state. There is. Moreover, the trunk route connects the start point and end point of the unconnected signal created using the empty through hole.

By displaying empty through holes and trunk routes as a guide for determining wiring routes for unconnected signals, it becomes possible to determine wiring routes between unconnected signal terminals in a short time.

[Example 1] Hereinafter, an example of the wiring route determining method according to the present invention will be explained in detail with reference to the drawings.

Fig. 1 is a diagram showing an example of a display in which empty through holes and trunk routes are superimposed on an existing wiring pattern based on the present invention;
The figure shows an example of an existing wiring pattern, Figure 3 is a diagram showing an outline of a device implementing the present invention, Figure 4 is a diagram showing the through hole position where through holes can be placed, and Figure 5 is a diagram showing an empty space. A flowchart explaining the processing procedure for extracting through holes, Figures 6, 7, and 9 are diagrams explaining the creation of a directed graph by adding arcs between nodes, and Figure 8 is a flowchart explaining the procedure for determining the main route. It is a flowchart explaining a processing procedure. In Figures 1 to 4, 1 is a first-layer wiring route, 2 is a second-layer wiring route, 3 is a component terminal, 4 is a through hole, 5 and 6 are unconnected signal terminals, 7 is an unconnected signal section, and 8
is an empty through hole, 9 is a main route, 41 is a basic grid,
42 is a sublattice, 43 to 50. T is the through hole wiring possible position, CADF is the storage device, LDPS is the wiring status display system, FLI○ is the file input/output section, D P P S
data processing unit, DPI○ is display input/output processing unit, DP
L is an image display device, DPC is a terminal control unit, and CRT is a display cathode ray tube.

In the example of the existing wiring pattern shown in FIG. 2, the first layer wiring route 1 is a horizontal wiring route, the second layer wiring route 2 is a vertical wiring route, and the through hole 4 is a wiring route for the first and second layers. This is a through hole that connects 1 and 2. and,
This existing wiring pattern is created by a conventional automatic wiring program or the like, and can be displayed on a CRT or the like.

In such an existing wiring pattern, unconnected signal terminals 5 and 6 that could not be wired are left behind by an automatic wiring program, etc., and in the case of the conventional technology, an operator needs to connect these unconnected signal terminals 5 and 6. The unconnected signal section 7 must be determined by searching for it using unused through holes not shown in FIG. 2 while changing the connections of the already wired sections.

FIG. 1 shows a wiring pattern in which the vacant through-hole 8 determined according to the present invention and the trunk route 9 between the unconnected signal terminals 5 and 6 are superimposed on the existing wiring pattern shown in FIG. be. In FIG. 1, an empty through hole 8 is extracted from the wiring state of an existing wiring pattern and a design rule, and a main route 9 is created from this empty through hole.

In the present invention, as described above, the empty through hole 8 and the main path 9 between the unconnected signal terminals 5 and 6 can be shown superimposed on the existing wiring pattern generated by an automatic wiring program or the like, so that the operator can By changing the connection of the existing wiring pattern at a position along the trunk route 9 in the displayed wiring pattern, it is possible to determine a route for connecting the unconnected signal terminals 5 and 6.

FIG. 3 is a block diagram showing a configuration example of a device for displaying wiring status according to the present invention as shown in FIG.
The image display device 1WDPL includes an image display device 1WDPL and an image display device 1WDPL. In FIG. 3, the storage device CADF stores existing wiring patterns based on wiring terminal information and inter-terminal wiring information generated by an automatic wiring program, wiring prohibition information, design rule information, etc. In order to carry out the present invention, these pieces of information are read into the wiring status display system LDPS via the file input/output unit FLIO within the wiring status display system LDPS.

When the terminal control unit DPC in the image display device DPL issues an empty through hole and trunk route display command, the display input/output processing unit DPIO in the wiring status display system LDPS
receives this and transmits it to the data processing unit DPPS.

Based on this command, the data processing unit DPPS determines a search area for extraction from the start point terminal and end point terminal of the instructed unconnected signal, extracts an empty through hole 8 from within that area, and extracts the empty through hole 8 from the area. 8, the trunk route 9 is determined. The extracted vacant through-holes 8 and main routes are transferred as graphic data to the image display device DPL via the display input/output unit DPI○, and displayed on the display cathode ray tube CRT.

As a result, a pattern diagram of empty through holes 8 and trunk routes 9 based on the present invention shown in FIG. 1 is obtained as a display screen.

FIG. 4 shows through-hole positions that can be physically arranged in a grid consisting of a basic grid 41 and a sub-grid 42.

In FIG. 4, a basic lattice 41 is a lattice determined by component terminal positions and intervals between component terminals, and is shown by solid lines in FIG. The sub-lattice 42 is a lattice provided between the basic lattices 41, and in the example of FIG. 4, two sub-lattice 42 are arranged between the basic lattices 41 and are shown by dotted lines. In addition, the through hole positions that can be physically placed are the basic lattice 4.
Only 1 above.

The processing procedure according to the present invention for extracting empty through holes from the through holes arranged in this manner will be explained below with reference to the flowchart shown in FIG.

(1) Based on the wiring specification that the number of wiring grids between the basic grids is 2 and through holes can be placed only in the basic grids, as described above, a general description of the case where the through holes are placed at the position T where the through holes can be placed as shown in Figure 4. The line capacitance is determined, and 80% of this line capacitance is set as a threshold value. The total line capacitance is determined by the number of unused through holes included in the area shown in Fig. 4, which is expanded by one basic grid in the vertical and horizontal directions from the through hole position T, and the wiring direction in which wiring can be performed from the unused through holes. The total number of lattices included in the area shown in FIG. 4 is added to the product of . For example, in FIG. 4, if the through holes placed at the four through hole positions 43 to 46 are unused through holes, there are eight wiring directions from each through hole, including diagonal directions. , Since there are seven wires in the horizontal direction and seven in the vertical direction, the total line capacitance mentioned above is obtained as 4x8+7+7=46, and the threshold value is about 37 (step a).

(2) Read the start point and end point of the unconnected signal (step b).

(3) Find a search area expanded vertically and horizontally by N basic grids from the start and end points of the unconnected signal. The number of basic lattices N to be expanded is generally set to about 5 (step C
).

(4) An unused through hole in the search area, in this case,
Take out the through hole at position T (step d).

(5) The arrangement status of through holes at positions 43 to 46 arranged in the area shown in Fig. 4, which is an enlarged view of one basic lattice vertically and horizontally from the extracted through hole at unused position T, and the basic lattice. and the existing wiring status of the sub-lattice, calculate the cost indicating the wiring difficulty level when the through hole at position T is selected as a vacant through hole. For example, the cost is
It is determined by the following formula.

TC=Kt XTn+L However, TC is the cost indicating the wiring difficulty level of the unused through hole, Kt is the coefficient that causes interference with other wiring due to the through hole placement, and Tn is the through hole position 43 in Fig. 4.
The number of through holes arranged at 46 and L is the number of already wired paths in the area shown in FIG. 4 (step e).

(6) The cost is compared with the threshold value obtained in steps a and e, and it is determined whether or not the hole can be adopted as a vacant through hole (step f).

(7) In step f, if the cost is less than the threshold value, the unused through hole is selected as a vacant through hole (step g).

(8) Check whether all unused through holes in the search area have been searched, and if not, repeat the process from step d and end (steps h, i)
.

The starting point of the unconnected signal is selected from all the unused through-holes in the predetermined area by the above-mentioned processing procedure.

Empty through hole 8 that can be used to connect end points
is obtained, and by displaying this, the arrangement of empty through holes 8 shown in FIG. 1 can be obtained.

Next, the creation of a directed graph by arcing using the vacant through-holes obtained as described above as nodes, and the method for determining the trunk route will be described.

Note that a node is composed of a starting point terminal and an ending point terminal of an unconnected signal, and an empty through hole, and arcing means connecting nodes with a branch having a direction.

Fig. 6 is a directed graph in which the start point terminal S, end point terminal E, and empty through holes t□ to t4 of unconnected signals are set as nodes, and arcs are formed between them by inter-node edges e1 to e14, and the thick line indicates the main route. This is what is shown.

FIG. 7 is a diagram for explaining the method of attaching arcs between nodes.Hereinafter, the attaching of arcs between nodes will be explained using flowchart 1-, which shows the processing procedure for creating a directed graph shown in FIG.

(1) In FIG. 7, the vacant through hole of interest with an arc is taken out, and this is set as the node of the vacant through hole of interest T with an arc (step A).

(2) Other nodes on the horizontal and vertical basic grids that pass through the through hole T, in the case of the example in FIG. 7, the through hole h5.
h6. Attach hl and h7 hair arcs (step B).

(3) Determine the presence or absence of arc occurrence (step C
).

(4) If an arc is generated in step C.

Since this arc exists parallel to the basic lattice 41,
The cost addition point V is set to 0 (step D).

(5) If arc cannot be generated in step C,
Other nodes on the upper and lower, left and right basic grids that are one basic grid away from the through hole T, in the case of the example in FIG. 7, the through hole h3. h4. h8. Add hlo and hll hair arcs (Step F).

(6) Determine the presence or absence of arc occurrence (step G
).

(7) If an arc is generated in step G, this arc is oblique to the basic lattice 41, so the cost addition point V is set to 100 points (step H).

(8) If an arc cannot be generated between nodes within one basic grid, the cost addition point V is set to 1000 points (Step E).

(9) Using the cost addition point (■) obtained in steps D and H when an arc is generated, calculate the cost indicating the difficulty level of wiring for the arc. This cost can be calculated using the following equation.

EC = TC (D÷2 This is the cost addition point shown (Step J).

(10) By repeatedly performing the following steps.

The cost calculations for all arcs are performed, and the arc attaching process ends when the cost calculations for all arcs are completed (step L).

The above-mentioned arc attachment has a cost addition of 10 points in the process.
In the case of 00 points, the directed graph becomes a disconnected graph as shown in FIG. 9 (b), and a portion where no arc is formed occurs. In this case, an arc shown by a dotted line is added between the subset graphs G1 and 02, and the graph is edited into a connected graph as shown in FIG. 9(a).

The directed graph obtained in this way is used to search for a route with the minimum cost 1, for example, by the well-known Dijkstra method, etc., and as a result, the trunk route 9 shown in FIG. 1 can be obtained. .

The above-described embodiment of the present invention has been described assuming that the wiring board has two layers, and extracting empty through holes and creating a trunk route. However, the present invention is also applicable to cases where the wiring board has multiple layers. In this case, empty through holes may be extracted in units of two layers.

The vacant through holes extracted as described above and the created trunk route are displayed on the image display device DPL under the control of the display input/output processing unit DPIO. At this time, the display input/output processing unit DPI○ displays only the extracted empty through hole, and also displays one or both of the trunk route and the straight line connecting the unconnected signal terminals on the display device DPL. Furthermore, existing wiring information may be displayed in an overlapping manner.

Based on the information displayed as described above, the operator can easily route wiring by reducing the number of man-hours required to create wiring routes for the start and end points of unconnected signal terminals that could not be wired using automatic wiring programs, etc. The route can be determined.

[Effects of the Invention] As explained above, according to the present invention, when determining a wiring route by displaying the wiring status of a printed wiring board, etc., empty through holes and a trunk route created based on the empty through holes are displayed. can be displayed superimposed on the existing wiring pattern, so by using such a display screen, it is possible to significantly reduce the number of man-hours required to determine a new wiring route for unconnected signals.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of a display in which empty through holes and trunk routes are superimposed on an existing wiring pattern based on the present invention;
The figure shows an example of an existing wiring pattern, Figure 3 is a diagram showing an outline of a device implementing the present invention, Figure 4 is a diagram showing the through hole position where through holes can be placed, and Figure 5 is a diagram showing an empty space. A flowchart explaining the processing procedure for extracting through holes, Figures 6, 7, and 9 are diagrams explaining the creation of a directed graph by adding arcs between nodes, and Figure 8 explains the processing procedure for determining the trunk route. This is a flowchart. 1...1st layer wiring route, 2...2nd layer wiring route, 3...Component terminal, 4...Through hole, 5, 6...・Unconnected signal terminal, 7...
・Unconnected signal section, 8...Empty through hole,
9... Main route, 41... Basic grid,
42...Sublattice, 43-50. T...
Possible through hole placement position, CADF...Storage device, LDPS...Wiring status display system, F
LI○...File input/output section, DPPS...
...Data processing unit, DPI○...Display input/output processing unit, DPL...Image display device, DPC...
...Terminal control unit, CRT...Cathode ray tube for display. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 8 Figure 9

Claims (1)

[Claims] 1. Existing wiring information and wiring prohibition information based on wiring terminal information and inter-terminal wiring information of a wiring board stored in a storage device;
The display includes an input/output processing section that reads design rule information, etc., a data processing section that processes input information and creates data to be displayed on a display device, and a display input/output section that controls the display of the data. In a wiring route determination method that determines a wiring route between unconnected terminals based on information displayed on a device, the data processing unit extracts unused through holes from the already wired information, wiring prohibition information, and design rule information. ,
Based on the wiring situation around the through-hole, an empty through-hole is extracted from the unused through-holes, a trunk path between unconnected signal terminals is created from the extracted empty through-hole, and the display input/output processing unit is a wiring route determination method characterized by displaying extracted empty through holes on a display device. 2. The wiring route determining method according to claim 1, wherein the data processing section extracts empty through holes in units of two layers when the wiring board is a multilayer wiring board. 3. The display input/output processing section displays one or both of the straight lines connecting the trunk route and the unconnected signal terminals on the display device in an overlapping manner in the vacant through-hole. The wiring route determination method described in item 1. 4. The wiring route determining method according to claim 3, wherein the display input/output processing section further displays the existing wiring information in an overlapping manner on a display device.