JPH0620005A - Computer aided design system - Google Patents

Abstract

PURPOSE:To make the best use of a wiring pattern set before the change of a design and to improve the design changing efficiency by restoring the saved wiring pattern to the pin of the changed parts and to the parts pin of a net list. CONSTITUTION:The wiring pattern to be deleted based on the results of comparison obtained between the old and new parts information and between the old and new connection information is saved into a memory 33 for patterns to be deleted. Then the wiring pattern saved in the memory 33 is restored to the pin of a changed parts or to the parts pin of a changed net list. In this case, a check means 49 applies the design rule check DRC to the wiring pattern and at the same time a restoring means 50 restores successively the wiring patterns. These restoring operations are carried on until the DRC is cleared. Thus the design can be effectively changed for the substrate pattern diagram corresponding to a circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CAD system for supporting the design of printed circuit boards. More specifically, the present invention relates to a CAD system capable of efficiently changing the design of a board pattern diagram corresponding to a circuit diagram when the design is changed in the circuit diagram of the substrate.

[0002]

2. Description of the Related Art Recently, a CAD system for designing a printed circuit board with the help of a computer has become popular. In a CAD system of this type, when designing a printed circuit board based on circuit diagram data, a pattern diagram of the printed circuit board is created based on a netlist generated from the circuit diagram. Here, a net is a collection of component pins connected to the same wiring line (hereinafter referred to as a net), and a net list is a list of such nets. The netlist consists of component information and connection information. The part information defines what kind of part is used when creating a printed circuit board. The connection information defines the connection state between the terminals of the parts used. If a design change occurs in the circuit diagram after designing the pattern of the printed circuit board using such a CAD system, the board pattern diagram must be modified accordingly.

FIG. 6 is a flow chart showing a procedure of design change in a conventional CAD system. In the process according to this flowchart, when there is a design change, the old and new netlists are compared to add and delete components and delete wiring patterns. Specific processing will be described according to a flowchart. First, the old and new parts information is compared. As a result of the comparison, the changed old component and the deleted old component are deleted from the graphic data of the board pattern diagram. Next, the wiring pattern connected to the component pin of the deleted component is deleted from the graphic data of the board pattern diagram. Further, based on the new component information, the changed new component and the added new component are added to the graphic data of the board pattern diagram. Here, the old and new connection information is compared. As a result of the comparison, in the changed netlist, the wiring pattern connected to the deleted component pin is deleted from the graphic data of the board pattern diagram.

In such a procedure, the processes A1 and A2
Although the wiring pattern is deleted by, the deletion is a process of deleting all the patterns related to the changed netlist. Therefore, there is a problem that the wiring pattern is deleted too much. Therefore, it takes a lot of man-hours to restore or correct the deleted pattern after processing the design change.

A specific example will be described. 7 and 8 are diagrams showing pattern examples in which a problem occurs when the design is changed in the procedure shown in FIG. In these figures, (a) is a board pattern diagram before design change, and (b) is a board pattern diagram after design change.

FIG. 7 shows a case in which part net pins of a part of a long wiring pattern are changed. In this case, the netlists before and after design change are as follows. [Netlist before design change] Connection information NET001: IC1-6, R1-2, D1-1, IC
5-8 [Netlist after design change] Connection information NET001: IC1-6, R1-2, D1-1, IC
5-7 In this netlist, before the design change, the contents of the net NET001 corresponding to the pattern P1 are the 6th pin of IC1, the 2nd pin of resistor R1, the 1st pin of diode D1, and the 8th pin of IC5. This means connecting to the same wiring line. Due to the design change, the 8th pin of IC5 was changed to the 7th pin. In this design change, in the process A2 of FIG. 6, the wiring pattern connected to the 8th pin of the IC5 is searched, and the pattern is deleted up to the branch point of the pattern P1 as shown in FIG. 7B. The broken line in FIG. 7B is the part where the pattern is deleted. Therefore, after the design change, the operator has to manually restore the originally usable pattern again.

FIG. 8 shows a case in which a component R1 having a component pin arranged at the center is changed in a net composed of three component pins. In this case, the netlists before and after design change are as follows. [Netlist before design change] Component information R1: RES0001, 50.0, 10.0, 9
0.0 Connection information NET0001: IC1-6, R1-2, IC2-8 [Netlist after design change] Parts information R1: RES0002, 50.0, 10.0, 9
0.0 Connection information NET0001: IC1-6, R1-2, IC2-8 Component information of the net list before design change, R1 is a component name, RES0001 is a symbol name, 50.0, 1
0.0 is the X and Y coordinates of the position of the component, and 90.0 is the placement angle of the component. Due to the design change, the component R1 has the symbol name R
Change from ES0001 to RES0002. In this design change, the entire wiring pattern P2 of FIG. 8 is deleted in the process A1 of FIG. The broken line in FIG. 8B is the part where the pattern is deleted. In the case of FIG. 8, only the parts are changed, and the wiring pattern P2 should be left as it is. However, since the wiring pattern P2 is entirely deleted, the operator has to manually restore the wiring pattern P2. As described above, in designing the board, the wiring pattern is often deleted more than necessary.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and when a design change was made from the circuit diagram side, it was present before the design change on the board pattern diagram side. It is an object of the present invention to provide a CAD system that maximizes patterns and realizes efficiency in design changes.

[0009]

SUMMARY OF THE INVENTION The present invention is a CAD system for designing a printed circuit board by creating a board pattern diagram based on circuit diagram data, and when the circuit diagram data is changed, Deleting means for deleting the wiring pattern connected to the component pin to be deleted from the graphic data of the board pattern diagram, a memory for saving the graphic data of the wiring pattern to be deleted by this deleting means, and a new component after the change An additional means for adding a pin to the graphic data of the board pattern diagram and a wiring pattern connected to the new component pin after the change are searched for, and the new pattern after the change is selected among the wiring patterns saved in the memory. Design rule check for the search pattern and wiring pattern to temporarily restore if there is something that can be connected to various component pins And a reviving means for sequentially reviving and growing the wiring pattern temporarily revitalized by the searching means while checking with the checking means, and reviving it as an actual pattern up to the range where the check is cleared. It is a CAD system characterized in that

[0010]

According to the present invention, when the circuit diagram data is changed, the wiring pattern deleted by the change is saved in the memory on the side of the board pattern diagram, and the new component pin after the change is saved. On the other hand, the saved wiring pattern is restored. When reviving, the wiring patterns are sequentially revitalized and grown while performing the design rule check, and are restored to the range where the check is cleared.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. Figure 1
FIG. 1 is a configuration diagram showing an embodiment of the present invention. In FIG. 1, 1 is an input device, 2 is an output device, 3 is a storage device, and 4 is a computer.

In the input device 1, 11 and 12 are a graphic input section and a keyboard for inputting information of a printed circuit board to be designed by graphic information and key input information, respectively. The input device 1 may be provided with a mouse or the like in addition to these input means. In the output device 2, 2
Reference numeral 1 is a display unit for displaying a printed circuit board to be designed. In the storage device 3, 31 is a circuit diagram memory in which circuit diagram data of a printed circuit board to be designed is stored. The circuit diagram memory 31 has a netlist before the design change (old netlist) and a netlist after the design change (new netlist).
Is stored. Reference numeral 32 is a board pattern diagram memory for storing a board pattern diagram of a printed circuit board to be designed by graphic data, and 33 is a delete pattern memory for saving graphic data of a pattern deleted in design change.

In the computer 4, 41 is a control unit for receiving an input from the input device 1 and writing / reading to / from the storage device 3, and 42 is a control unit 41.
It is a netlist creating means for creating a netlist from the input received in step 3 and storing it in the circuit diagram memory 31. Four
3 is a pattern creating means for creating a board pattern diagram based on the netlist stored in the circuit diagram memory 31 and storing it in the board pattern diagram memory 32; and 44 is a display control means for controlling the display of the display section 21. Is. Reference numeral 45 is a comparison means for comparing the new netlist and the old netlist when there is a design change, and 46 and 47 are deletion means and addition means. As a result of comparison by the comparison means 45, a pattern to be deleted and a pattern to be added. Are deleted and added to the graphic data of the board pattern diagram memory 32. Reference numeral 48 is a search means for searching a wiring pattern connectable to a component pin of a new component after design change, and 49 is a design rule check (hereinafter referred to as DRC) for the wiring pattern.
Checking means 50 for carrying out the above, and 50 is a restoring means for restoring the deleted wiring pattern within the range where the DRC is cleared.

The operation of the CAD system thus constructed will be described. FIG. 2 is a flowchart showing a procedure of design change in the CAD system of FIG. The processes B1, B2, and B3 of FIG. 2 are different parts from the flowchart of FIG. In the flowchart of FIG. 2, the processes B1 and B2
As shown in, the wiring pattern that is to be deleted as a result of the comparison of the old and new component information and the result of the comparison of the old and new connection information is saved in the deletion pattern memory 23.
Then, in the process B3, the wiring pattern saved in the deletion pattern memory 23 is restored for the changed component pin or the changed component pin of the netlist.

FIG. 3 is a flow chart showing a concrete procedure of the process B3 in FIG. The process shown in this flowchart is performed for all the component pins of the changed component and all the component pins of the changed netlist. The processing shown in the flowchart of FIG. 3 will be outlined. Parts information,
Starting from the component pin that has changed in the connection information,
The wiring pattern is grown according to the new connection information. When there is no wiring pattern to be grown in the new connection information, a connectable one is searched for from the wiring patterns saved in the deletion pattern memory and provisionally restored. DRC is performed on the temporarily restored wiring pattern. DRC
If the result is OK, the temporarily restored wiring pattern is restored as an actual pattern. In this way, the wiring pattern is sequentially grown until the counterpart component pin is reached or the DRC is cleared, and the wiring pattern saved in the deletion pattern memory is restored.

FIGS. 4 and 5 are pattern diagrams of the same wiring patterns as those in FIGS. 7 and 8 when the design is changed by using the CAD system according to the present invention. Figure 4
And in FIG. 5, (a) is a board pattern diagram before design change,
(B) is a board pattern diagram after a design change. In FIG. 4, the wiring pattern is restored from the point A to the point B, as shown in FIG. Since the DRC will not be cleared if the pattern is further grown, the growth is stopped at the point B. The part surrounded by the broken line is the part that has been revived. In FIG. 5, all wiring patterns are restored as shown in FIG. As shown in these drawings, it is not necessary to manually redraw the deleted wiring pattern later.

Note that what is restored is not limited to the wiring pattern, but may be a via, a jumper wire, or the like.

[0018]

According to the present invention, the following effects can be obtained. When there is a design change process from the circuit diagram side, the board pattern diagram side saves the wiring patterns deleted by the design change to the memory, and the component pins of the changed component and the changed net. Restore the saved wiring patterns for the component pins in the list. As a result, the wiring pattern before the design change can be utilized to the maximum extent, so that the efficiency of the design change can be realized. Since the wiring pattern is revived and grown from the changed component pins, it is not necessary to check in detail when deleting patterns in the pre-processing, the wiring pattern connected to the changed component pins. Can be deleted collectively. As a result, the time required for design change can be shortened. When the wiring pattern is restored and grown, the DRC is sequentially restored while performing the DRC.
A wiring pattern that clears C is obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation procedure of the CAD system of FIG.

3 is a flowchart showing an operation procedure of the CAD system of FIG.

FIG. 4 is a diagram showing an example of a wiring pattern whose design has been changed by the CAD system of FIG.

5 is a diagram showing an example of a wiring pattern whose design has been changed by the CAD system of FIG.

FIG. 6 is a flowchart showing a processing procedure of a conventional CAD system.

FIG. 7 is a diagram showing an example of a wiring pattern whose design has been changed by a conventional CAD system.

FIG. 8 is a diagram showing an example of a wiring pattern whose design has been changed by a conventional CAD system.

[Explanation of symbols]

 1 Input Device 2 Output Device 21 Display Unit 3 Storage Device 31 Circuit Diagram Memory 32 Board Pattern Diagram Memory 33 Delete Pattern Memory 4 Computer 46 Deletion Means 47 Addition Means 48 Search Means 49 Recovery Means 50 Check Means

Claims (1)

[Claims] 1. In a CAD system for creating a board pattern diagram based on circuit diagram data and designing a printed circuit board, when the circuit diagram data is changed, it is connected to a component pin to be changed or deleted. The deletion means for deleting the existing wiring pattern from the graphic data of the board pattern diagram, the memory for saving the graphic data of the wiring pattern deleted by this deletion means, and the new component pin after the change are displayed in the graphic of the board pattern diagram. An additional means to be added to the data and a wiring pattern connected to the new component pin after the change is searched, and among the wiring patterns saved in the memory, one that can be connected to the new component pin after the change If there is, a search means for temporarily resuming it, a check means for performing a design rule check on the wiring pattern, The wiring pattern temporarily restored by the searching means is sequentially restored and grown while being checked by the checking means, and is restored as an actual pattern up to the range where the check is cleared. C
AD system.