JPH0221633A - Wiring system - Google Patents

Abstract

PURPOSE:To enable automatic wiring by determining leading-out direction so as to shorten the wiring length from a terminal on a circuit element, determining the position of a trunk line in the manner in which wirings led out from terminals in the same net can be connected by one trunk line, and connecting the wirings led out from the terminals and the trunk line to complete the whole wiring. CONSTITUTION:When the terminal leading-out direction is set in y-direction, the trunk line length becomes '2' from the spread of terminal (x) coordinate. When it is set in x-direction, said length becomes '6' from the spread of terminal (y) coordinate. As the result, the terminal is determined so as to be led out in y-direction. As to nets where the terminal leading-out direction is identical, the net of a terminal 6 and the net of a terminal 7 perform terminal leading-out in y-direction. In order that branch lines may not overlap each other, an upper- lower restriction graph to assign a trunk line 9 in the upper part of the trunk line 10 is produced. In order to satisfy the upper-lower restriction, an assignment position is so determined that the trunk line 9 situates on the upper position of the trunk line 10. As to a trunk line 11, the assignment position is determined in the manner in which the trunk line 11 does not overlap on the trunk lines 9, 10. By extending branch lines from the assigned position which has been already determined, to each terminal, wiring is completed. Thereby, oblique wiring and incomplete wiring can be avoided while enabling automatic wiring with short length wiring, so that the irregularity of signal delay time can be reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an automatic wiring method for diagonal wiring, and more particularly to an automatic wiring method suitable for various kinds of high-speed LSIs and printed circuit boards used in computers, etc. .

[Conventional technology]

Conventionally, regarding the diagonal wiring method, the Printed Circuit World Convention IV (1987) WC
IV-3 (PRINTED CIRCUITWORLDC
ONVENT-1ON IV WCIV-3) This article discusses automatic diagonal wiring for printed circuit boards, including delay specified wiring, line search methods, and high-speed wiring length specified wiring.

[Problem to be solved by the invention]

The above conventional technology has a problem in that the number of unwired wires (the number of wires that could not be wired by automatic wiring) is large. The reason for this is that since wiring is done on a first-come, first-served basis, nets that are wired first become obstacles and nets that are wired later cannot be allocated. That is, as shown in FIG. 2, the wires cannot be drawn out from the terminals 2 due to the previously allocated net 1.

An object of the present invention is to solve the above-mentioned wiring order problem, reduce unwired parts, and perform high-speed automatic wiring.

[Means to solve the problem]

The above object is achieved by a processing scheme as shown in FIG.

First, as shown in FIG. 3, for all the nets 1- to be wired, select (a) from FIGS. 3(a) and 3(b) so as to shorten the wiring length in the lead-out direction of the terminals 4 to 6.

(200) At this time, the wiring length is calculated using a coordinate system as shown in FIG.

Next, based on the predetermined terminal pull-out direction, the height wiring (
Considering connecting the branch lines (referred to as branch lines) with one wiring (referred to as the main line), the main line 9 should be connected to the main line 10 so that the main lines overlap and the branch lines of different nets do not overlap, as shown in Figure 4. A vertical constraint graph (FIG. 4(C)) representing the need for allocation above is created. (201) Next, based on the vertical constraint graph, the main line position is determined as shown in FIG. 4(b) so that the main lines do not overlap, and the branch line is extended to the terminal position, thereby completing the connection process. (202
, 203) For example, in FIG. 4(C), when the main line is allocated from the smaller of the two coordinates.

By allocating the trunk line 10 before allocating the trunk line 9, it is possible to prevent the trunk line 9 from becoming unwired.

[Effect]

By determining the terminal drawing direction first, the length of the main line does not change depending on the position of the main line, so that a vertical constraint graph is determined.

Furthermore, by creating a vertical constraint graph, branch lines do not overlap.

In addition, in wiring length calculation, by making each terminal in the same net lead out in the same direction, the trunk length can be uniquely determined. In other words, if the branch line direction is y, the spread of the X coordinate of the terminal is the main line length, and if the branch line direction is X according to the same method,
The extent of the X coordinates of the terminals is the main line length. Therefore, the trunk length can be calculated before the trunk position is determined. Here, a three-axis coordinate system as shown in FIG. 3 is used as the coordinate system.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 3 to 5. In Figure 3, the coordinates of terminal 3 are (4,1°O) and terminal 4
is (2,5,·3), and terminal 5 is (4°7.3).

The terminal pull-out direction is in the y direction.The main line length is terminal X.
It is 2' from the spread of the coordinates, and when taken in the X direction, it is 6' from the spread of the terminal X coordinates. Therefore, Figure 3(a)
We decide to pull out the terminal in the y direction as shown in the figure below. (200 in FIG. 1) In this way, in the case of FIG. 4(a).

Determine the terminal drawing direction as shown in FIG. 4(b).

Next, a vertical constraint graph is created for nets with the same terminal extraction direction. In FIG. 4(b), terminal 6's terminal 1~
The net of terminal 7 and terminal 7 are projecting in the y direction.

Here, since some terminals have the same X coordinate, a vertical constraint graph (FIG. 4(C)) is generated which means that the main line 9 is allocated above the main line 1o so that the branch lines do not overlap. (201 in Figure 1) This ensures that the branch line can be extended from the main line to the terminal.

Next, in order to satisfy the vertical constraints, the allocation position is determined so that the main line 9 is above the main line 10, and the main line 11 is placed above the other main line 9.
, 10 so as not to overlap. (1st
(202 in the figure) Furthermore, by extending the branch line from the already determined allocation position to each terminal (203 in Figure 1), the fourth (b)
The wiring shown in the figure is obtained.

FIG. 5 shows a case where the wiring grid is vertical, and wiring can be done using the same processing method. In this case, the trunk direction is the vertical direction.

As described above, according to the present embodiment, by using the coordinate system as a three-axis coordinate system, vertical constraints can be taken into consideration, and since It< does not exist in the wiring order, trunk line 9 is assigned to the bottom, and then
There are fewer unwired lines because there is no need to assign wires that depend on the wiring order. Furthermore, by selecting the direction in which the terminals are drawn out, wiring results with short wiring lengths can be obtained.

[Effects of the Invention] According to the present invention, it is possible to automatically route diagonal wiring with fewer unwired lines and shorter wiring lengths, thereby reducing variations in signal delay time and making it possible to produce integrated circuits of various types capable of high-speed operation in a short period of time. Manufacturable.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a processing method according to an embodiment of the present invention, FIG. 2 is a flowchart showing an example of the prior art, and FIG.
The figures are wiring diagrams for two types of terminal extraction directions, and Figures 4 and 5 are detailed explanatory diagrams of the present invention. ...Net, 2-8...Terminal, 9-11 ・Main line. Diagram and genus diagram (b) (C)

Claims (1)

[Claims] 1. In a method of wiring in which multiple circuit elements are arranged in a row and using diagonal wiring and wiring in the longitudinal direction of the element rows, the wiring is drawn out from the terminal on the circuit element so that the wiring length is shortened. Wiring is performed by determining the direction, determining the position of the main line, and connecting the wiring drawn from the terminal and the main line so that the wiring drawn from the terminals in the same net can be connected with one main line. Wiring method.