JPH02292845A - Wiring path deciding device - Google Patents

Abstract

PURPOSE:To make it possible to average congestion of a wiring so as not to need the improvement of the passage of the wiring subsequently to the wiring while a wiring length is considered by a method wherein a means to find the evaluation values of candidate segments is provided with a means to find a number of expected passing wirings, a means to find an expected passing probability, a means to find an easy lead-out of the following segment and a means to find the wiring length. CONSTITUTION:When a schematic path, which consists of a plurality of terminals, of a signal is found within a wiring region, a wiring path deciding device is provided with a wiring capacitance control means, a candidate segment generating means, a means to find the evaluation values of candidate segments and a means to compare the evaluation values and the means 10 to find the evaluation values is provided with a means 1 to find a number of expected passing wirings, a means 2 to find an expected passing probability, a means 3 to find an easy lead-out of the following segment and a means 4 to find a wiring length. Thereby, the best segment among the candidate segments is selected, congestion of wiring in the whole region is averaged without lengthening the wiring length and an unwired wiring in the final result is eliminated. Moreover, for example, while a wiring lattice utilized at the time of wiring like the above is fractionized one after another, the schematic path is designed in detail to contrive to complete the whole wiring.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a semiconductor integrated device and a printed circuit board device.
In particular, it relates to those designed by automatic wiring equipment.

[Conventional technology]

Conventional equipment achieves a given wiring length while controlling detours (Japanese Patent Application Laid-Open No. 61-55780), or generates virtual lines to avoid overlapping routes and wires via them (Japanese Patent Application Laid-Open No. 61-55780). 61-68672) was used.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into consideration the problem of wiring congestion in the wiring area, and when the wiring becomes locally crowded, it is necessary to once route the wiring and then improve the route to eliminate unwired lines.

An object of the present invention is to obtain the expected number of lines passing through and the expected passage probability in advance, and to average wiring congestion so that route improvement is not necessary after wiring, while taking into account the wiring length.

[Means to solve the problem]

The above object is achieved by means for calculating four evaluation values and means for comparing them, which constitute the means for calculating evaluation values, for each candidate line segment generated by the candidate line segment generation means.

[Effect]

Each of the four means constituting the means for determining the evaluation value will be explained.

The method of calculating the expected number of passing signals is to give the number of signal wires that are expected to pass through a certain area or a certain boundary line, and while performing multiple signal wires, calculate how many signals have already passed and how many more are left. Detect whether there is a possibility of passing.

The means to calculate the expected passage probability is to give the probability that each route of each signal counted in the expected number of passages will pass through that area or boundary line, and use this together with the expected number of passages to calculate the expected value of how many more signals will pass. Detect. The method for determining the ease of generating the next line segment is to calculate how easily a line segment will occur in the direction perpendicular to the line segment that is currently being determined, if the line segment that is currently being determined does not complete the connection. To detect.

The means for determining the wiring length detects the sum of the line segments whose starting and ending points have already been determined in the wiring for one signal, and detects the difference from the wiring length that is considered to be the shortest.

The expected number of passages and the expected passage probability work so that it is difficult for a signal to pass through a location where it is thought that a large number of signals will pass during wiring. Furthermore, the ease with which the next line segment can be drawn is determined so that a large number of candidate line segments can be generated in the next step, and a line segment that does not interfere with other routes is selected. The wire length works to avoid extreme detours. By combining these four means for determining evaluation values, it is possible to average wiring congestion and eliminate unwired lines while taking the wiring length into consideration.

(Example〕 An embodiment of the present invention will be described with reference to FIGS. 1 to 6.

FIG. 2 shows the configuration of a device for determining a rough route.

This device includes a candidate line segment generating means, an evaluation value determining means,
It consists of means for comparing evaluation values and capacity management means. As shown in FIG. 6, the candidate line segment generating means 12 generates a line segment 57 that has already been determined in determining the route between the terminals indicated by 51 and 52.
When finding a line segment perpendicular to , a portion where the boundary line capacitance is zero is detected, and candidate line segments 53 to 56 between them are found. Line segments cannot pass through areas where the capacity is zero.

The means 10 for determining the evaluation value consists of four means as shown in FIG. Means 1 for calculating the expected number of passing trains is as shown in Figure 3 (
In a), create the minimum rectangle that includes the set of terminals 22 and 23 to be connected, and assume that the boundary line that the inside of the rectangle (including the outer frame of the rectangle) passes through is the path that connects the terminals. , add 1 to the border. Therefore 22 and 2
The overlapping portion of the rectangles created by the set of 3 terminals is 2 as shown in FIG. 3(b). There are still zero points where the rectangle does not pass. Means 2 for calculating the expected passage probability is similar to the means for calculating the expected number of passages, by creating a rectangle shown in FIG. is given as the passing probability. As shown in FIG. 3(c), since the rectangle of the terminal set 22 is 4 in width and 6 in height, 1/4 is given to the horizontal boundary line and 1/6 to the vertical boundary line. The portion that overlaps with the terminal set 23 becomes the sum of probabilities.

The means 3 for determining the ease of drawing the next line segment will be explained with reference to FIG. It is assumed that candidate line segments 34 to 36 orthogonal to the previous level line segment 33, which has already been determined to be adopted as part of the wiring between the terminals 31 and 32, have been found. Since the candidate line segments 34 to 36 have not yet reached the terminal 32, it is necessary to find further line segments perpendicular to 34 to 36.

Therefore, the degree to which line segments orthogonal to 34 to 36 are easy to draw for each of 34 to 36 is evaluated. This will be explained by taking the candidate line segment 36 as an example. Inside the rectangle 38 created by the candidate line segment 36 and the y-coordinate of the terminal 32, a point 37 indicated by Δ is a point where the boundary line capacitance is zero. By evaluating how many points of Δ there are in the rectangle, it is determined how easy it is to generate the next orthogonal line segment from the candidate line segment 36.

Similar processing is performed for candidate line segments 34 and 35. The means 4 for determining the wiring length will be explained with reference to FIG. The wiring length between the terminals 41 and 42 is determined by the length Q1+Ω2 of the determined route 43.44, the previous level line segment 50 (the line segment that generated the candidate line segment), and the candidate line segments 45 to 49. The length QB is determined by the subsequent path search. Since Ω1 and ρ2 have already been determined, the candidate line segment 45~
49, the wiring length Q3 when the candidate line segment is selected is evaluated. This Q8 is similarly evaluated for the next level orthogonal line segment to control the overall wiring length.

An evaluation value is obtained by combining these four means and evaluated by the comparison means 13. The candidate line segment with the best evaluation value is set as the determined route, and the route information is sent to the easy management means 11. The capacity management means 11 subtracts 1 from the boundary line capacity determined in advance for the boundary through which the route has passed.

By repeating the four steps 10 to 13 for each signal, the rough wiring of all signals is completed.6 According to this embodiment, wiring is done while taking into consideration the congestion of the wiring area and the wiring length, so the route A rough route without local concentration of wiring congestion can be obtained without any improvement.

Next, an example will be described in which the above-mentioned means are replaced with other means.

First, we replace the means for calculating the expected passage probability with the actual degree of congestion. The actual degree of congestion is the ratio of how many wires have passed through the boundary line to the initial wiring capacity defined on the boundary line of the approximate wiring grid. By evaluating the actual congestion level, congestion can be dynamically avoided.

Furthermore, by calculating the difference between the expected passage probability and the actual degree of congestion, it is possible to predict how often the arrangement is likely to pass through that boundary line in the future.

The means for determining the wiring length dynamically calculates the wiring length, so that the wiring can be accurately determined. However, since calculation time is required, for signals where the wiring length constraints are not strict, the wiring length is managed by limiting the route search area and limiting the number of bends (see FIG. 7).

The route search area is a rectangle created by multiplying the rectangle created between the terminals by a certain standard magnification, and wiring is performed within the rectangle. The number of bends is determined by the permissible detour rate, but it is generally considered to be within 3 to 4. If this means is used, wiring can be done at high speed, and the amount of information to be stored for searching can be reduced.

When calculating the expected number of passages and the expected passage probability, if the number of terminals in one signal is three or more, it may be divided into terminal pairs and values may be calculated between each terminal pair.

At this time, the decomposition into terminal pairs is performed in order of shortest distance between the terminals.

Above, we have described an example for finding a rough route.
By subdividing the rough route search grid, it is possible to route the rough route until it becomes a detailed route. This will be explained using FIG. First, find a rough route, then create a mid-level rough grid (divide it into 4 parts. It doesn't have to be 4 parts, just have to divide it equally.), and then create a mid-level route. It is calculated using the same evaluation value as the rough route. The number of intermediate levels is not particularly defined, and is determined based on the area of the wiring region and the approximate size of the wiring grid at the highest level. Finally, use a detailed grid to find detailed routes.
According to this method, it is possible to conduct detailed wiring that can maintain the wiring length while monitoring the congestion of the entire wiring area.

〔Effect of the invention〕

According to the present invention, the wiring length between logic circuits can be controlled without locally congesting the wiring, so that wiring can be performed without unwired lines and with fewer detours.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a means for determining an evaluation value, which is the central part of the present invention, Fig. 2 is a schematic block diagram of the entire wiring, and Fig. 3 (a)
(b) (Q) is a diagram showing the means for determining the expected number of passing lines and the expected passing probability, Figure 4 is a diagram showing the means for determining the ease of drawing the next line segment, and Figure 5 is a method for determining the wiring length. FIG. 6 is a conceptual diagram of means for determining candidate line segments, and FIGS. 7 and 8 are diagrams showing other embodiments. 1... Means for obtaining the expected number of passing lines, 2... Means for obtaining the expected passage probability, 3... Means for obtaining the ease of drawing the next line segment, 4... Means for obtaining the wiring length, 10...・Means for determining evaluation values, 11...Capacity management means, 12...
Candidate line segment generation means, 13... comparison means. Zj No. 1/4z No. 6l Kayaguchi 6l

Claims (2)

[Claims] 1. When determining the approximate route of a signal consisting of a plurality of terminals in a wiring area, wiring capacity management means, candidate line segment generation means,
In a device having a means for determining the evaluation value of a candidate line segment and a means for comparing the evaluation values, the means for determining the evaluation value includes a means for determining the expected number of passages, a means for determining the expected passage probability, and a means for determining the ease of coming out of the next line segment. By having a method and a means for determining the wire length, it is possible to select the best line segment among the candidate line segments, average the wire congestion over the entire area without increasing the wire length, and reduce the final result of unwired lines. Eliminate wiring route determination device. 2. 2. A wiring route determining device as claimed in claim 1, which completes all wiring by subdividing a wiring grid used in wiring one after another to refine a rough route into details.