JPH03290762A - Detachable rewiring method - Google Patents

Abstract

PURPOSE:To enable high-density wiring while keeping the performance of a printed circuit board by detecting a detachable wired pattern from wired patterns and defining the wired pattern, which allowable length range of wiring bypass is largest, in these detected patterns as a detachable object block. CONSTITUTION:In an area including an unwired block, a processor 1 detects an existent detaching object wiring block so as to wire the unwired block. The allowable length of the wiring bypass is previously read from a wiring design support file 3 and the respective wiring bypass allowable lengths of the detected existent wiring blocks are compared and the existent wiring block equipped with the longest wiring bypass allowable length is detached. Then, the unwired block and the detaching object block are wired again. Thus, the high-density wiring is enabled while keeping the wiring performance.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a wiring method in the wiring design of a printed circuit board, and in particular, when wiring an unwired section of a printed circuit board, it is necessary to remove the already wired section and leave the unwired section. The present invention relates to a wiring method that takes into consideration the wiring detour length of a removed section in a method of wiring a wiring section and rewiring a removed existing wiring section.

[Prior art] As a conventional technology regarding the pull-in and rewiring method in printed circuit board wiring design, for example, IEICE technical research report VLD88-86-94 February 2, 1989
A technique described as "Efficiency improvement and evaluation of r-pulling and rewiring method" is known in pages 39 to 46 of this paper.

This conventional technology connects unwired sections by removing appropriate existing wiring using a certain evaluation function, connecting the unwired sections, and then reconnecting the removed wiring sections. This is what we do. but,
When this conventional technology is applied to high-speed printed circuit boards with severe circuit constraints to realize high-density wiring, using the evaluation function of this conventional technology requires a delay value for the routed section. However, there is a problem in that the minimum delay value is exceeded and the substrate performance deteriorates.

[Problems to be Solved by the Invention] In the prior art described above, when wiring an unwired section, an evaluation function is used to remove a suitable wiring pattern, and after wiring the unwired section, the removed section is routed. This made it possible to route unwired sections. However, the above-mentioned conventional technology has a problem that the delay value of the generated wiring may exceed the required minimum delay value because the evaluation function does not take into account the wiring detour length of each wiring section. are doing.

An object of the present invention is to solve the problems of the prior art described above, to realize high-density wiring while maintaining the performance of printed circuit boards with severe circuit constraints, and to take into account the permissible wiring detour length of each wiring section. The object of the present invention is to provide a removal and rewiring method that can perform wiring without exceeding a necessary delay value.

[Means for Solving the Problems] According to the present invention, the object is to read wiring detour tolerance range information from a wiring design support file when wiring a certain unwired section using the removal and rewiring method, Read section information from the wiring design file, detect removable existing wiring patterns from among the existing wiring patterns,
Remove the existing wiring pattern with the largest allowable wiring detour length as the section to be removed, reroute the unwired section and the section to be removed, select the section to be removed until both are less than the allowable wiring detour length, and perform rewiring. This is achieved by repeating the process of removing and rewiring so that each wiring section is equal to or less than the permissible wiring detour length.

1. When attempting to route a certain unwired section, detect a removable existing wiring pattern from among the existing wiring patterns,
By selecting the existing wiring pattern with the largest allowable wiring detour length range among these existing wiring patterns as the section to be removed, the delay value of each wiring section can be reduced to a small value, and the board performance can be maintained. can.

[Example 1] Hereinafter, an example of the removal and rewiring method according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a processing system that implements the removal and rewiring method according to the present invention;
The figure is a flowchart explaining the process of removing and wiring an existing wiring section when wiring an unwired section, and Figure 3 is a table that stores information necessary for rewiring the already wired section and unwired section. FIG. 4 is a diagram showing an example of a wiring pattern before removal and rewiring, and FIG. 5 is a diagram showing an example of a wiring pattern after removal and rewiring. In FIG. 1, 1 is a processing device, 2 is a wiring design file, 3 is a wiring design support file, 4 is a display device, 5 is a keyboard, and 6 is a printer device.

A system for carrying out the wiring method according to the present invention is configured as shown in FIG. 1, and each device making up the system has the following functions.

When wiring an unwired section, the processing device 1 executes a process of removing the existing wiring section having the largest allowable wiring detour range and rewiring.

The wiring design file 2 is a magnetic disk device, and stores the coordinate information of each bin in the already wired section on the printed circuit board. Further, the wiring design support file 3 is a magnetic disk, and stores information on permissible wiring detour ranges for each bin, which is necessary for determining removal of an existing wiring section.

The display device 4 displays the results of the processing performed by the processing device 1 on a screen such as a CRT so that the operator can visually see them. Further, the keyboard 5 is an input device used when inputting printed circuit board information or the like manually.

The printer device 6 is a device for printing out necessary information such as processing results in order to keep it at hand.

In one embodiment of the present invention, which is comprised of devices having the above-mentioned functions, each wiring section is removed and rewired within the permissible wiring detour range according to the flow shown in FIG.

For example, it is assumed that four LSis are mounted on a printed circuit board as shown in Fig. 4, and that they are already interconnected by wiring as shown in ■ to ■. It is assumed that the unwired sections A1 and A2 are to be wired. In this case, it is necessary to remove one of the already wired sections (2) to (2) and perform rewiring.

According to the present invention, the unwired section A shown in FIG.
1 to A2 are removed and rewired, as shown in FIG. 5. Details of this removal and rewiring processing will be explained with reference to the table shown in FIG. 3 and the processing flow shown in FIG. 2. do.

(1) First, the processing device 1 detects an existing wiring section to be removed, in which the unwired section can be wired, in a region including the unwired section. For example, when wiring the unwired sections A1 to A in FIG. 4, the sections a, to a,
, section S, ~b,, section C1-c2, section d, ~d
When the unwired sections e1 to e2 are removed, the unwired sections A and -A2 can be wired, so these are detected (step 11).

In addition, in the detection of the wiring section to be removed, if there is a wiring such as a clock wiring that should not be removed, these are excluded from the wiring section to be removed.

(2) The processing device 1 reads in advance the allowable wiring detour lengths as shown in FIG. 3 from the wiring design support file 3, and compares each of the allowable wiring detour lengths of the existing wiring sections detected in step 11. Then, remove the existing wiring section with the largest allowable wiring detour length. For example, as shown in FIG. 3, the largest permissible wiring detour length is the existing wiring sections c, to C3, and a process is performed to remove these wiring sections C8 to c2 (step 12).

(3) Wire the wired sections and unwired sections that were removed in step 12 (step 13).

(4) Check whether each section wired in step 13 is less than or equal to the permissible wiring detour length (step 14).

(5) In step 14, if any of the wiring results exceeds the wiring detour allowable length, for example, unwired sections A, ~A2
If the wiring result exceeds the allowable length, it is determined whether all sections to be removed have been checked (step 15).

(6) As a result of the determination in step 15, if there is an unchecked section, in this example, since four sections other than the existing wiring sections 01 to C2 with the largest allowable wiring detour length are unchecked, the wiring section C construction ~C2 is returned to the state before being removed, that is, the original state as shown in FIG. 4 (step 16).

(7) Next, remove the existing wiring section having the next largest permissible wiring detour length from the remaining sections to be removed. For example, as shown in FIG. 3, the already wired section having the next largest wiring detour allowable length is the section b1 to c2.
b2, so this existing wiring section b1-b2 is removed (step 17).

(8) After that, the process from step 13 is repeated, and the sections removed in step 17 and the unwired sections are wired, and in step 14, each section wired in step 13 is determined to be less than the allowable wiring detour length. For example, when both sections are less than the allowable length, it is checked whether all unwired sections have been processed (step 18).
.

(9) If it is checked in step 18 that there are remaining unwired sections, return to step 11, repeat the above-mentioned process, and after completing the rewiring process for all unwired sections, finish the removal and rewiring process. do.

According to the embodiment of the present invention described above, the routed sections that can be removed are determined in consideration of the permissible length of the wiring detour, and the unrouted sections are routed and k) the removed already routed sections are rewired. As a result, each wiring section can be wired with a wiring detour allowable length or less, that is, with a necessary delay value.

[Effects of the Invention] As described above, according to the present invention, when removing an already routed section and wiring an unrouted section, the routed section is removed in consideration of the allowable range for wiring detour, and the rerouted section is replaced by a section. Since the wiring can be determined after confirming that it is within the allowable range for specific wiring detours, each wiring section can be routed within the allowable range for wiring detours, allowing high-density wiring while maintaining wiring performance. This makes it possible to shorten the period required for manual correction of printed wiring boards.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of a processing system that implements the removal and rewiring method according to the present invention;
The figure is a flowchart explaining the process of removing and wiring an existing wiring section when wiring an unwired section, and Figure 3 is a table that stores information necessary for rewiring the already wired section and unwired section. FIG. 4 is a diagram showing an example of a wiring pattern before removal and rewiring, and FIG. 5 is a diagram showing an example of a wiring pattern after removal and rewiring. 1...Processing device, 2...Wiring design file, 3...Wiring design support file, 4...
... Display device, 5 ... Keyboard, 6
・・・・・・Printer device. Figure 2

Claims (1)

[Claims] 1. In order to wire an unwired section, a removable already wired section is searched among a plurality of already wired sections, and the existing wired section is removed and the unwired section is wired. In the rewiring method, among the searched removable already routed sections, the routed section with the largest permissible wiring detour length is removed, and the unrouted section is routed and the removed already routed section is rerouted. A removal and rewiring method characterized by: 2. In the removal and rewiring method described in claim 1, the wiring detour length of the unwired section routed by the method and the rerouted routed section is calculated, and this wire detour length is determined in advance. If at least one wiring detour length exceeds the wiring tolerance length, remove the next longest existing wiring section,
The process of wiring unrouted sections and rewiring already routed sections,
A removal and rewiring method characterized in that the method is repeatedly executed until there are no more removable existing wiring sections.