JPH05151317A - Designated length wiring path searching system - Google Patents

Abstract

PURPOSE:To execute the designated length wiring with high accuracy, in the case a net which necessitates wiring with wire length designated in advance such as a clock net, etc., has plural terminals. CONSTITUTION:A net to which a designated length wiring is requested is extracted (step 101), and to an extracted net unit, a wiring length adjusting section and a wiring length unadjusted section are determined (step 105). The wiring length unadjusted section is subjected to path search by a conventional method (step 107), and by subtracting the sum total of wiring length of the wiring unadjusted section from designated length, its difference is derived (step 110), and by regarding the derived difference as theoretical length of the wiring length adjusting section, a search of a designated length wiring path of one wiring section is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a designated length wiring route searching system, and more particularly to a route searching system for wiring a multi-fanout wiring length designated net such as a printed circuit board.

[0002]

2. Description of the Related Art In a conventional specified length wiring method for a printed circuit board, a specified length is obtained for each section and specified length wiring is performed in each wiring section. Alternatively, the specified length wiring is performed by calculating the theoretical length of one certain wiring section so that the specified length is obtained before the net wiring.

[0003]

In the above-mentioned conventional specified length wiring system, since the individual specified length wiring is performed for the net which requires a large number of fan-outs and the specified length wiring, the wiring of each wiring section is performed. The error of length accumulates,
There is a drawback that the error from the specified wiring length becomes large when viewed as a net.

Further, even when the theoretical length is calculated in advance before wiring the net, there is a disadvantage that the wiring length of the other wiring section causes a large difference between the wiring length of the net and the designated wiring length.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a net for which a specified length is requested and a specified wire length are extracted from a net which is wired with a specified length to satisfy a wiring delay condition such as a clock net. Net / designated wiring length extraction means, adjustment section determination means for determining a section for adjusting the wiring length to satisfy the specified wiring length in the extracted net, and wiring sections other than the determined wiring length adjustment section And a difference length calculation means for calculating a difference between the specified wiring length of the net and the wiring length of the wiring, and a specified length wiring means for wiring a section for adjusting the wiring length based on the calculated difference. There is.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a flow chart showing the flow of processing in one embodiment of the present invention.

First, in the processing box 101, nets which are required to be wired with the designated wiring length L are extracted. In the judgment box 102, it is judged whether or not all the nets having the designated length wiring request extracted in the processing box 101 have been processed,
If there is an unprocessed net, proceed to the processing box 103,
In addition, when all are processed, the process ends. Processing box 10
At 3, one unprocessed designated length wiring request net is taken out.
Then, in the processing box 104, the designated wiring length L of the designated length wiring request net is extracted.

In the processing box 105, the processing box 1
For the designated length wiring request net extracted in 03, one wiring length adjustment section in which the designated length wiring is taken into consideration and a remaining wiring length unadjusted section in which the remaining designated wiring length is not taken into consideration are determined. Here, the theoretical lengths of the wiring length unadjusted sections are respectively set to l1, l2, l
, ..., In (n: number of sections of the net-1).
The method of determining the wiring section at this time is the same for any method such as one-stroke writing.

In the judgment box 106, the processing box 1
It is checked whether or not all the wiring length unadjusted sections determined in 05 are processed. If the processing of all the wiring length unadjusted sections is completed, the process proceeds to the processing box 110, and if not, the processing box 107 proceeds. In the processing box 107, one wiring length unadjusted section is taken out and the wiring route search is performed by the conventional method. Here, the wiring length r of the i-th (i ≧ 1) section
i is li + Δli (Δli is the difference between the wiring length and the theoretical length)
Becomes

In the judgment box 108, it is judged whether or not the route of the wiring length unadjusted section for which the wiring route search is tried can be found. When the wiring route can be found, the judgment box 10
If the wiring route cannot be found, the process goes to the processing box 109. In the processing box 109, the wiring length unadjusted section in which the route search has failed in the processing box 107 is replaced with the wiring length adjustment section determined in the processing box 105 or the wiring length adjustment section previously replaced in the present processing box 109. Here, when the wiring length adjustment section is a section in which the wiring route search has already been tried, it is considered that the specified length wiring of the net is impossible, and the process proceeds to the determination box 102.

In the processing box 110, the total wiring length Σru (i = 1 to n) of the obtained wiring length unadjusted section is calculated, and the difference 10 with the designated wiring length L extracted in the processing box 104 is calculated.
Ask for.

L0 = L−Σrj = L− {l1 + Δl1) + (l2 + Δl2) + ... + (ln + Δln)} In the processing box 111, based on the length of the difference l0 with the designated wiring length obtained in the processing box 110. The specified length wiring route to be routed is searched.

FIGS. 2A and 2B are views showing the image of the designated length wiring for explaining the conventional method and the designated length wiring route search method of the present invention.

In FIG. 2A, reference numeral 21 designates terminals of a net for which a connection is requested, the theoretical lengths of the wiring length unadjusted sections are l1 and l2, and the wiring lengths of the wiring length unadjusted section are r1 and r2, respectively. And If the logical length of the wiring length adjustment section obtained from the difference between the designated wiring length L and the sum of the logical lengths of the wiring length unadjusted sections is l0 and the wiring length is r0, then l0 = L- (l1 + l2) r0 = l0 + Δl0 (Δl0 indicates an error from the actual wiring length r0 when the wiring is tried with the logical length l0) r1 = l1 + Δl1 r2 = l2 + Δl2, and the actual wiring length R is R = r0 + r1 + r2 = (l0 + Δl0) + (l1 + Δl1) + (L2 + Δl2) = L− (l1 + l2) + Δl0 + (l1 + Δl1) + (l2 + Δl2) = L + (Δl0 + Δl1 + Δl2), and Δl0 + Δl1 + Δl2 for the designated wiring length L.
Error occurs.

Next, in FIG. 2B, the wire lengths r1 and r2 in the wire length unadjusted section are set, and the wire length adjustment is obtained from the difference between the specified wire length L and the sum of the wire lengths in the wire length unadjusted section. If the logical length of the section is 10 'and the wiring length is r0', then 10 '= L- (r1 + r2), and the actual wiring length R'is R' = r0 '+ r1 + r2 = (10' +. DELTA.10 ') + r1 + r2 = L + 10. ′, An error of Δ10 ′ occurs with respect to the designated wiring length L.

Further, although it is possible to search the wiring length designated wiring route for the section of l1 and l2, there is a problem that the wiring property is deteriorated due to the processing time and the designated length wiring.

[0018]

As described above, according to the present invention, it is necessary to perform wiring with a specified length in order to satisfy wiring delay such as a clock net, and in the wiring of a net having many fan-outs,
To adjust the wire length in the last wire section of the net,
This has the effect of reducing the error with respect to the specified wiring length.

[Brief description of drawings]

FIG. 1 is a flowchart showing a processing flow of an embodiment of the present invention.

FIG. 2 is a diagram showing an image of designated length wiring for explaining a conventional method and a designated length wiring route search method of the present invention.

[Explanation of symbols]

21 Net terminal with connection request 22 Wiring length adjustment section 23 Wiring condition unadjusted section L Net specified wiring length R Net wiring length l0 Theoretical length of wiring length adjustment section (not Manhattan length) l1, l2 Wiring length unadjusted Theoretical length of the section (Manhattan length) r1, r2 The wiring length of the wiring length unadjusted section Δl0 The difference between the wiring length and the theoretical length in the wiring length adjusted section Δl1, Δl2 The difference between the wiring length and the theoretical length in the wiring length unadjusted section

Claims (1)

[Claims] 1. A request net / designated wiring length extraction means for extracting a net for which a designated length wiring is required and a designated wiring length for a net which is to be routed with a designated length to satisfy a wiring delay condition, and the extracted said Adjustment section determining means for determining a section for adjusting the wiring length to satisfy the specified wiring length in the net, and a section other than the determined wiring length adjustment section are wired and wired with the specified wiring length of the net. A designated length wiring route searching method, comprising: a difference calculation means for obtaining a difference from the wiring length; and a designated length wiring means for wiring a section for performing the wiring length adjustment based on the obtained difference.