JPS6322352B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is utilized for automatically designing a connection pattern for a printed circuit board on which a plurality of integrated circuits are mounted. In particular, it is used as a printed circuit board design device that can perform high-density wiring.

[Conventional technology]

It is equipped with a key input device, a CRT image display device, a photoprinter, and a drill control information output device, and a central processing unit that is connected to each of these devices and controls them, and a memory connected to this central processing unit. This central processing unit includes:
The connection pattern on the printed circuit board is calculated according to the connection information on the printed circuit board given from the key input device, and the figure of the calculation result is displayed on the above CRT image display device and as a photomask on the above photo plotter. An automatic printed circuit board design device is known that is configured to output hole positions on the printed circuit board to a drill control information output device as control information for an NC drill device. With this device, connection patterns of complex circuit wiring mounted with a large number of integrated circuits can be designed at high speed and efficiently.

In such a device, when the coordinate positions of two pins to be connected on a printed circuit board are given as connection information from a key input device, a possible and rational wiring route between them is automatically searched for. Hitherto, the following methods have been known to automatically search for this wiring route: 1. Line segment search method 2. Pattern method 3. Maze method.

[Problem that the invention seeks to solve]

The line segment search method is the simplest method. When two points to be connected are given, line segments are searched alternately horizontally or vertically on the coordinates from one point to the other. This will be extended.
Although this method requires a short search time, the resulting connection patterns are limited to simple ones, and high-density wiring cannot be performed.

In the pattern method, several connection patterns are prepared in advance and this pattern is selected and applied between two pin coordinates. Even if this could be done, it is not appropriate to design the whole thing this way. That is, to design the entire design using only this method, it is necessary to prepare and store an extremely large number of patterns, and the processing time for selection becomes long, making it impractical.

The maze method involves a large number of trials and errors to find a maze between two given points. Although this method allows for high-density wiring, it generally requires an extremely large number of trials and errors. This has the disadvantage of increasing the number of searches, which increases the amount of time it takes to search.

The present invention was made against this background, and enables high-density and rational wiring design.
Moreover, it is an object of the present invention to provide an efficient printed circuit board design device with a short processing time for necessary searches.

[Means for solving problems]

The present invention provides means for defining a mesh divided into vertical and horizontal grids on the front and back surfaces of the printed circuit board at minimum wiring intervals according to information regarding the shape of the designed printed circuit board so that the meshes on the front and back surfaces match;
A horizontally long connection pattern provided along the mesh on one surface of this printed circuit board, a vertically long connection pattern provided along the mesh on the other surface of this printed circuit board, and a longitudinally long connection pattern provided along the mesh on the other surface of this printed circuit board. A conductor inserted through a hole penetrating the front and back of the printed circuit board at the intersection of the long connection pattern and the horizontally long connection pattern connects two points according to the connection information given from the input device. means for calculating a pattern to be formed, and the calculating means scans tracks along the mesh in the horizontal or vertical direction within a range in which a connection pattern can be provided, and calculates the number of existing holes on each track. a means for counting n, and according to the counting result of this means, tracks with the smallest number n are selected in order, and a hole through which the conductor is inserted is set on the track, and a connection pattern corresponding to this hole is set. The method is characterized in that it includes means for trying increasing the number n until it is successful.

〔Example〕

Next, examples will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an example of an embodiment of the present invention. This device is equipped with a CRT image display device 1, a keyboard device 2, and an input tablet device 3 at the operating position, and these are connected to an input/output interface 4. Furthermore, this device includes a central processing unit 5, a storage device 6 connected to the central processing unit 5, a photoplotter 7, and a drill control information output device 8.

The central processing unit 5 has a built-in microprocessor and controls each device connected to the input/output interface 4. The photoplotter 7 is connected to the central processing unit 5 via the input/output interface 4, and outputs the calculation results of the central processing unit 5 as photographic graphic information for photomask. The drill control information output device 8 is connected to the central processing unit 5 via the input/output interface 4, and outputs the calculation results of the central processing unit 5 to the NC drill device (the drilling position is automatically controlled according to the given control information). This information is output as control information for the drilling equipment used.

In a device configured in this way, connection information between two points that need to be connected to each other among a large number of pins or terminals of integrated circuits and other components arranged on a printed circuit board is transmitted to the keyboard device 2 or Coordinate values are input from the input tablet device 3. The central processing unit 5 performs arithmetic processing on this, determines it as a connection pattern on the printed circuit board, and uses this result as a connection pattern.
It is displayed on the CRT image display device 1 and outputted to the photoplotter 7 as photographic graphic information for photomask. It also outputs NC drill control information regarding the hole position of the printed circuit board to the drill control information output device 8. Here, the drill control information output device 8 is a drilling tape output device. The drilling tape output from this device is supplied to the NC drilling device, and the NC drilling device automatically drills holes as designed in the printed circuit board according to the information on the drilling tape. Can be done.

To explain the characteristic operation of the present invention, first, information regarding the shape of the printed circuit board to be designed for which a connection pattern is to be designed is input, and a mesh is defined on the surface of the printed circuit board divided into vertical and horizontal grids with minimum wiring spacing. . This situation is shown in FIG. In this example, one grid of the mesh, which is a square whose four sides are formed by this minimum wiring spacing, is two squares of adjacent integrated circuits.
Two pins should be placed between the book pins. That is, this minimum wiring spacing is set to one third of the spacing between two pins of the integrated circuit. More specifically,
Since the standard integrated circuit pin spacing is 2.54 mm, the width of one mesh square is 0.847 mm. One wiring conductor is formed within this width so as not to come into contact with the adjacent wiring conductor. Also, any one of the squares of the mesh on this printed circuit board is the base point (X=
0, Y=0), each square is represented by XY coordinates.

This mesh is set so that it overlaps the front and back sides of the printed circuit board, and is represented by the same XY coordinates on both sides.

Information such as connection information from an input device can also be specified using these XY coordinates.

Here, it is possible to form arbitrary connection patterns on both the front and back sides of the printed circuit board to be designed, but the connection pattern on the front side is as shown by the diagonal line downward to the left in Figure 2. It is formed to be longer in the horizontal direction, and the connection pattern on the back is the second
As shown by the diagonal line slanting downward to the right in the figure, the principle is to make it longer in the vertical direction. By adopting this principle, it becomes easier to separate the intersections of the connection patterns into front and back sides, and the soldering process becomes advantageous in the printed circuit board manufacturing process.

Further, locations where a long connection pattern can be formed in the horizontal direction on the front surface of the printed circuit board and locations where a long connection pattern can be formed in the vertical direction on the back surface of the printed circuit board are defined as tracks. In FIG. 2, the area indicated by diagonal lines downward to the left is one track on the surface of the printed circuit board. In FIG. 2, the area indicated by diagonal lines downward to the right is one track on the back surface of the printed circuit board.

Now in Figure 2, from one pin position P ₁ to another 1
Considering the case of wiring to pin position P ₄ ,
First, a connection pattern is set on the vertical track on the back side, as shown by the broken line, starting from point _P1 , and reaches the first hole position _P2 . A hole is provided at this position _P2 as shown by the cross mark, and the wiring is exposed on the surface of the printed circuit board through a conductor that passes through this hole. From this hole position _P2 , a connection pattern is set in a horizontal track on the surface of the printed circuit board, as shown by the solid line in FIG. 2, and the next hole position _P3 is reached. A hole is made at this position P ₃ as shown by the cross mark, the wiring passes through this hole and migrates to the back side, and a connection pattern between positions P ₃ and P ₄ as shown by the broken line is created on the vertical track. Set. In this way, the wiring is extended, and pin positions _P1 and _P2 are connected by the wiring.

The positions indicated by circles in FIG. 2 are designated in advance as positions to which integrated circuits and other components are connected.

Here, in the device of the invention, when selecting the track, i.e. the hole positions (e.g. P ₂ and P ₃ )
When selecting a hole, selectable tracks in the vicinity are checked, and the track with the least number of holes already drilled is selected in the area where the connection pattern is to be formed. Fewer holes means less wiring.

More specifically, when setting up a new connection pattern according to the given information, each track along the mesh is scanned horizontally or vertically within the possible range for setting the connection pattern. , the number n of existing holes on the track is counted, and attempts are made to determine the position of the hole and to set a connection pattern corresponding to the hole in order from the track with the smallest value of n. In this way, an appropriate connection pattern that is less likely to conflict with other existing wiring can be quickly discovered.

The above-mentioned "range in which connection patterns can be set" refers to the range in which connection patterns can be physically set, as well as the range in which connection patterns can be set within a certain range so that connection patterns do not become meaningless. This means that a frame can be set and the area outside the frame can be an invalid area. Furthermore, the above-mentioned possible range means that once a connection pattern is set, an area that is clearly useless due to the existence of an existing connection pattern is set as an invalid area. For example, in Fig. 3, when setting the connection pattern from the starting point S to the position marked with an x mark, when track Tu is selected to select the horizontal track, the track Tu is selected from the starting point S to the vertical track including the starting point S. If it is found that an existing connection pattern exists up to Tu, there is no need to scan any tracks above track Tu, such as track Tc.
The same applies to the track below the starting point S, and the area indicated by diagonal lines in FIG. 3 is preferably set as an invalid area.

In the case where the wiring connection pattern passes through two holes, the procedure for setting the connection pattern will be described with reference to FIG. 4. In FIG. 4, S represents the starting point of the wiring, and E also represents the ending point.

(a) Scan the track in the lateral direction within the range where it is possible to set the connection pattern, and find the number n of existing holes on the track (FIG. 4A).

(b) Determine the hole positions p ₁ and p ₂ on the track from the smallest value of this number n (FIG. 4B).

(c) Search for a route that can be set from the starting point S to the ending point E.

(d) If the search fails, return to (b) above.

(e) When all searches have been completed for the horizontal tracks, the same process is performed for the vertical tracks (FIG. 4C).

In the case where the wiring connection pattern passes through three holes, the procedure for setting the connection pattern will be explained with reference to FIG. 5.

(a) Scan the track in the vertical direction within the range in which the connection pattern can be set, and find the number n of existing holes on the track. (Figure 5A).

(b) Pick out tracks in the vertical direction in descending order of the value of this number n, and use these as longitudinal relay tracks.

(c) Scan the vertical track including the starting point and the above-mentioned vertical relay track as a possible range for setting a connection pattern, and find the number n of existing holes on the horizontal track. , determines the right to choose the horizontal track (fifth
Figure B).

(d) Take out the horizontal tracks in the selected order and find the positions of hole positions p ₁ , p ₂ and p ₃・ Hole position p ₁ is the intersection of the vertical track including the starting point S and the horizontal track taken out above. - Hole position _p2 is the intersection of this horizontal track and the above vertical relay track. - Hole position _p3 is determined to be the intersection of the horizontal track including the end point E and the vertical relay track. (Figure 5C).

(e) Take out the horizontal tracks in the above selection order and repeat the above (d) until the connection pattern can be set.

(f) If the setting in (e) above fails for all the horizontal tracks extracted in (d) above, the vertical track including the end point E and the vertical relay track extracted in (b) above are A horizontal track is retrieved by scanning the horizontal track, the number n of existing holes on the track is determined, and the same operations as in (d) and (e) above are performed.
The hole positions p ₁ and p ₂ determined at this time are as follows: - Hole position p ₁ is the intersection of the horizontal track including the starting point and the above-mentioned vertical relay track - Hole position p ₃ is the vertical track including the end point This is the intersection of the vertical relay track and the above-mentioned vertical relay track (Fig. 5D).

Furthermore, in the case where the wiring connection pattern passes through three holes on the way, the procedure for setting the connection pattern will be explained with reference to FIG. 5.

(a) To the extent that it is possible to set the connection pattern between the starting point S and the ending point E, the number n of existing holes on the track in the longitudinal direction is determined, and the selection order is determined (Fig. 6). A).

(b) In this selection order, one vertical track is used as a vertical relay track.

(c) Scan between the vertical track including the starting point and the vertical relay track to determine the selection order of the first horizontal track (FIG. 6B).

(d) Scan between the vertical track including the end point E and the vertical relay track to determine the selection order of the second horizontal track (FIG. 6C).

(e) By the combination of the first lateral track and the second lateral track, the hole position p ₁ ~
_p4 - Hole position _p1 is the intersection of the vertical track including the starting point and the first horizontal track. Hole position _p2 is the intersection of the first horizontal track and the vertical relay track. - Hole position _p3 is the intersection of the second horizontal track and the vertical relay track. - Hole position _p4 is the intersection of the vertical track including the end point and the second horizontal track. (Figure 6D).

(f) Perform steps (a) to (e) above until it becomes possible to set a connection pattern between starting point S and ending point E according to the selection order above.
Repeat the operation.

(g) If the above (f) fails, use the horizontal track as a relay track and perform the same operations as in the above (a) to (f) (Fig. 6E).

FIG. 7 is a flowchart showing the operating procedure for progressing from two hole positions to three or four hole positions according to such operations.

In the above example, two tracks are placed between two pins of an integrated circuit, but when one track is placed between two pins, the width of one square of the mesh is is 1.27mm. In addition to this, the width of the mesh can be set arbitrarily.

〔Effect of the invention〕

In this way, the horizontal track and the vertical track are divided into the front and back, and the selection order of the tracks is determined from the one with the smallest number n of existing holes, and the position of the hole that penetrates the front and back is determined first, and then the connection is made. By trying to set the pattern, the number of trials and errors for setting the connection pattern is significantly reduced, and the designed connection pattern becomes efficient and rational, making it possible to realize high-density wiring. can.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing the mesh on the printed circuit board to be designed. FIG. 3 is a diagram illustrating a scanning range for track selection. FIG. 4 is a diagram for explaining the order of connection pattern setting when there are two holes. FIG. 5 is a diagram for explaining the order of connection pattern setting when there are three holes. FIG. 6 is a diagram for explaining the order of connection pattern setting when there are four holes. FIG. 7 is a flow chart showing the relationship between the case of two holes and the case of three or four holes.

Claims (1)

[Claims] 1. An input device, a CRT image display device, and a photo-image display device.
A printer, a drill control information output device, a central processing unit connected to each of the above devices to control each of the devices, and a storage device connected to this central processing device, and the central processing device includes the above input device. means for calculating the connection pattern and hole position of the printed circuit board according to the connection information for connecting two points on the printed circuit board given from the above; and means for recording the results calculated by this means in the storage device. ,
In the printed circuit board design apparatus, the printed circuit board design apparatus includes means for outputting the results to the CRT image display device and the photoplotter, and means for outputting the hole positions of the results to the drill control information output device. The apparatus includes a means for defining a mesh divided into vertical and horizontal grids at minimum wiring intervals on the front and back surfaces of the printed circuit board according to information on the printed circuit board to be designed such that the meshes on the front and back surfaces match; and one side of the printed circuit board. a horizontally long connection pattern provided along the mesh on the surface of the printed circuit board; a vertically long connection pattern provided along the mesh on the other surface of the printed circuit board; A pattern that connects two points according to the connection information given from the key input device is created by a conductor inserted into a hole penetrating the front and back of the printed circuit board at the intersection with the horizontally long connection pattern. and calculating means, the calculating means scans tracks along the mesh in the horizontal or vertical direction within a range in which a connection pattern can be set, and calculates the number n of existing holes on each track. a means for counting, and according to the counting results of this means, tracks with the smallest number n are selected in order, and holes through which the conductor is inserted are set on the tracks, and a connection pattern corresponding to the holes is set; the above number n until it succeeds
A printed circuit board design device characterized by comprising means for attempting to increase the number of printed circuit boards.