JP3177932B2 - Printed circuit board design equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer-aided printed circuit board design apparatus, and more particularly to an improvement in a route search method in automatic wiring.

[0002]

2. Description of the Related Art Conventionally, CAD (Computer Aided Des
ign) automatically or semi-automatically determines the layout of components, sets the print pattern, etc. to distribute the wiring density of the printed circuit board, shorten the total wiring length, etc. To save a lot of labor and time. When automatic wiring of a printed circuit board is performed by the printed circuit board designing apparatus, a search for a wiring path is performed. Conventional search methods include a line segment search and a rectangle search.

[0003]

By the way, although these line segment search and rectangle search are the basics of area search, since they are methods for searching all designated areas, there is a drawback that there are many useless searches. Was. In order to solve this drawback, for example, the search area is provided with directivity to reduce the useless search area, and at the same time, various search paths are stored, and it is confirmed that an optimum path exists in one of the search paths. A search method that guarantees (hereinafter referred to as an optimized path guarantee) can be considered. Note that when searching for a route from a specified area, the same area is searched many times to ensure the route, but this is necessary to ensure that the route is optimal when finding the route and must be avoided. It is an unsearchable search. However,
The same is guaranteed for a search area in a part unrelated to the route (that is, the same area is searched many times).
No need. The object of the present invention, in view of such a point,
It is not necessary to guarantee the search area in a portion irrelevant to the route in the same manner. Therefore, it is an object of the present invention to provide a printed circuit board design apparatus which can exclude the unnecessary area from the search.

[0004]

According to the present invention, there is provided an initialization processing unit having a function of designating a search start point and a search end point and registering the search start point and a search end point in a graphic database. Has a function of searching for an area in a form that gives priority to the direction of the target area from both the search end point and registering the trajectory in the graphic database, and ending the search when an intersection area searched from both is found An initial search processing unit and a reverse path search from the intersection area to the search start point and the search end point, respectively, and when a trajectory different from the current trajectory is found, the trajectory is registered as a different trajectory in the graphic database. A feedback area search unit having a function is provided.

[0005]

The first processing unit specifies a search start point (area) and a search end point (area). The initial search processing unit performs a route search from both the search start point and the search end point toward the other party. The search trajectory is registered in the figure database. If there is an area where both searches intersect (an area searched from both: an intersection area), it means that a route from the search start point to the search end point has been found, and the initial search ends. Next, the feedback area search unit performs a path search in the reverse direction each time from the intersection area. At this time, each time a new different trajectory is found, it is registered in the figure database each time. This search is repeated until the search start point and the search end point are reached. Through the above-described search, it is possible to optimize the route only in a necessary area.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
FIG. 1 is a configuration diagram showing one embodiment of a main part of a printed circuit board designing apparatus according to the present invention. The device of this embodiment includes a key input device 101, a CRT image display device 102, an output device 103, a processor 104, a storage device 105, and a bus 106 connecting these devices. The processor 104 reads various programs from the storage device 105 and executes them. For example, according to the connection information on the printed circuit board provided from the key input device 101, a connection pattern on the printed circuit board is obtained by arithmetic processing, the result obtained by the arithmetic processing is recorded on the recording device 105, and the CRT image display device 102 The display is controlled, and the output is further output to the output device 103 as necessary.

One of the arithmetic processing functions of the processor 104 is a route search (area search) for automatic wiring, and FIG. 2 shows a functional block of the route search. The processing mechanism having the area search function includes an initialization processing unit 201, an initial area search processing unit 2
02, comprising a feedback area search unit 203. The initialization processing unit 201 performs initialization processing, and registers a search start point (start and end). The initial area search processing unit 202 searches for an area from the start side and the end side, searches for an area that can be wired until the area becomes an “intersection area” that is also searched for from the other side, and stores the trajectory in a graphic database. Register with. The feedback search processing unit 203 searches in the reverse direction from the intersection area toward the start side and the end side, and in this case, if a new search trajectory is found, it stores it as another trajectory.

Next, the operation of such an area search mechanism will be described. In the present invention, it is assumed that the wiring area is divided into rectangular data. Obstacles (mounting areas for parts and the like) are formed in the shape of trapezoidal tiles, and other areas are tileable according to the dividing direction as wirable areas. The dividing direction is up / down or left / right. In the dividing direction of the routable area, there are obstacles or boundaries that are not routable.

(1) Initialization processing The initialization processing unit 201 specifies and registers the start and end of the search start area. This will be described by taking a graphic database as shown in FIG. 3 as an example. FIG. 3 shows an example in which the printed circuit board is divided into tiles.
The satin part S is the start tile specified as the search start area,
The other satin portion E is an end tile designated as a search end region. Numbers 1 to 23 are wiringable areas.

(2) Initial Search Processing As shown in the operation flow of FIG. 4, an initial search is performed in the following procedure. Starting from the specified area (Start S and End E)
The surrounding area (up, down, left, right) is searched. FIG. 5 shows a state of search (expansion) from the start tile S, and FIG. 6 shows a state of search (expansion) from the end tile E. The numbers in the figure are tile numbers, and the solid lines indicate that the tiles are connected. Check whether there is a routable area. If not, execute the NOP instruction and return to the above. NO
The P (no operation) instruction executes an instruction that does nothing, and is used here merely as a time limit.
If there is a routable area, the process proceeds to the next step. Checks if the specified area has already been searched by the other party. If the search is from the start S side, the search from the end E side is the partner side. If the other party has searched, the initial search process is terminated because the intersection area has been reached. If not, the process proceeds to the next step. Check whether the area has already been searched. If the area has already been searched not by the search of the other party but by the search of one's own side, the NOP instruction is executed and the processing shifts to the above processing. If the area has not been searched, the trajectory of the search is registered in the graphic database, and the process proceeds to the above processing.

Through such processing, a trace that can be wired is found. (3) Feedback search processing Searches in the reverse direction are respectively performed from the intersection area obtained in the initial search processing to the start side and the end side. The procedure will be described with reference to the operation flow of FIG. Check whether the given area is the search start tile (S or E). If the tile is the search start tile, the process ends. If not, proceed to the next process. Search the surrounding area from the specified area. Obtain a routable area. Checks if the current trajectory is the same as the previous trajectory. If the trajectories are the same, the process returns to the above process after executing the NOP command. If they are not the same, proceed to the next process. Checks whether the specified area is an unsearched area. In the case of the area being searched, the processing returns to the above processing after executing the NOP instruction. If the area is not searched, the process proceeds to the next processing. Check if the tile was found by the search on the other side.
If the other party has searched, the NOP instruction is executed, and then the process moves to the above. If not, the process proceeds to the next step. The current locus is newly registered as another locus. After registration, the process returns to the above process.

Through the above processing, if another trajectory is found, it is registered each time, and various kinds of paths are found as shown in FIGS. 8 and 9, and an optimized path is guaranteed. The trajectory and the graphic data are represented by the following structure in the C language expression, for example. The structure representing the trajectory of the area searched for in the search has the following format. typedef struct {Tile_Type * tile_ptr; figure database Search_tree * origin_ptr; trajectory before being searched Search_tree * next_ptr; another trajectory .....｝ Search_tree; You. typedef struct {Search_tree * search_start; start side track Search_tree * search_end; end side track .....｝ Tile_Type;

[0013] A path can be linked using such a structure. The depth of the link can be arbitrarily specified.

[0014]

As described above, according to the present invention, it is possible to optimize a route only in a necessary area without optimizing all the searched areas. This makes it possible to eliminate unnecessary optimization. In particular, it can cover the weakness of directivity due to route search,
Determining the linked direction ensures that the optimization path is linked. In addition, you can specify the depth to link the route data.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a main part of a printed circuit board design apparatus according to the present invention.

FIG. 2 is a diagram showing functional blocks related to a route search of a processor.

FIG. 3 is a diagram illustrating an example of a case where a printed circuit board is divided into tiles.

FIG. 4 is a diagram illustrating an operation flow of an initial search process.

FIG. 5 is a development view of a search area when a search is performed from a start S;

FIG. 6 is a development view of a search area when searching from the end E;

FIG. 7 is a diagram illustrating an operation flow of a feedback search process.

FIG. 8 is a development view of a search area from a start S after a feedback search.

FIG. 9 is a development view of a search area from an end E after a feedback search.

[Explanation of symbols]

 Reference Signs List 101 input device 102 CRT 103 output device 104 processor 105 memory 106 bus 201 initialization processing section 202 initial area search processing section 203 feedback area search section

Claims (1)

(57) [Claims] 1. A printed circuit board designing apparatus for performing automatic wiring using a rectangular search method with the aid of a computer, comprising: an initialization processing unit having a function of designating a search start point and a search end point and registering the search start point and a search end point in a graphic database; A region search is performed with priority given to the direction toward the target region from both the search start point and the search end point, and the trajectory is registered in the graphic database. When the intersection region searched from both is found, the search is performed. An initial search processing unit having a function of ending, a route search is performed in the reverse direction from the intersection area to the search start point and the search end point, and when a trajectory different from the current trajectory is found, the trajectory is different. A printed circuit board design apparatus comprising a feedback area search unit having a function of registering a graphic database.