JPH033347A - Wiring route searching method - Google Patents

Abstract

PURPOSE:To determine a wiring route wherein the crosstalk amount is restricted within an allowable value while unnecessary bend of wiring route is reduced to a minimum, by checking whether the crosstalk amount exceeds the allowable value every time when a new wiring route is searched, and trying again the search of wiring route by generating a segment limiter only in the case where the allowable value is exceeded. CONSTITUTION:A parallel wiring length calculating means 2 calculates, for every nets, the parallel wiring length between a searched wiring route and the other adjacent wiring route which has been wired. A crosstalk amount calculating means 3 obtains, for every nets, the amount of crosstalk based on the calculated parallel wiring length, which crosstalk is generated on a net with regard to a formed wiring route by a net whose wiring route is newly searched. A crosstalk amount judging means 4 refers the calculated crosstalk amount and judges, about a net whose wiring route has been determined, whether the crosstalk amount exceeds an allowable value. When a net whose crosstalk amount is judged to exceed the allowable value exists, a segment limiter is temporarily generated on the adjacent lattice of the wiring route in touch with said net, and different wiring routes are searched for while the segment limiter is taken into consideration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wiring route search method used for wiring design of printed wiring boards, ceramic wiring board integrated circuits, etc.

[Conventional technology]

When determining wiring routes for wiring sections to be connected in wiring design for printed wiring boards, etc., if you search for wiring routes without limit, the amount of crosstalk received from nets on adjacent wiring routes will exceed the allowable value and crosstalk will occur. This has the disadvantage of requiring a wiring route that may cause malfunction of the circuit due to noise.

So, for example, rN, niuwahara, S, Asam
t+N, Takano+N, NomuraH” A R
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As seen in 11゜250-253 J, each time a new wiring route is determined, line length limiters are generated at regular intervals on the wiring grid adjacent to the new wiring route, and these line length limiters are taken into account. A method has been proposed in which a wiring route is searched for the next unprocessed wiring section.

[Problem to be solved by the invention]

According to the conventional wiring route search method described above, each time a wiring route is determined, line length limiters are generated at regular intervals on the wiring grid adjacent to the wiring route, and the line length limiters are taken into account. Since the wiring route for the next unprocessed wiring section is searched, a wiring route with an amount of crosstalk exceeding the allowable value is not determined (this makes it possible to prevent circuit malfunctions due to crosstalk noise). becomes.

However, in the conventional wiring route search method, each time a new wiring route is determined, a line length limiter is generated unconditionally on the wiring grid adjacent to that wiring route, so in reality, the wiring route is Even if the wires become parallel, their lengths are short and the amount of crosstalk does not exceed the allowable value. However, the wire length limiter bends the wiring route, and this unnecessary bending causes a reduction in wiring efficiency. Ta.

The present invention solves these conventional problems, and its purpose is to determine a wiring route that suppresses the amount of crosstalk within an allowable value while reducing unnecessary bending of the wiring route. The object of the present invention is to provide a wiring route search method that can perform the following tasks.

[Means to solve the problem]

In order to achieve the above object, the present invention uses a wiring route search method that determines the wiring route of the wiring section to be connected in the wiring design of printed wiring boards, ceramic wiring boards, integrated circuits, etc., when searching for a new wiring route. , a parallel wiring length calculation means for calculating the parallel wiring length between the searched wiring route and the already routed other wiring route adjacent thereto, and a parallel wiring length calculation means for calculating the parallel wiring length for each net, based on the parallel wiring length calculated by the parallel wiring length calculation means. Crosstalk amount calculation means for calculating the amount of crosstalk given by the net for which the newly searched wiring route is applied to the net connected to the already wired other wiring route for each net, and taking into account the amount of crosstalk calculated by the crosstalk amount calculation means. and crosstalk amount determining means for determining whether the amount of crosstalk for a net for which a wiring route has already been determined exceeds an allowable value each time a new wiring route is searched,
If there is a net that is determined to exceed the allowable value by this crosstalk amount determination means, a line length limiter is temporarily generated in the adjacent grid of the wiring route that spans the net,
The apparatus is configured to search for another wiring route to replace the newly searched wiring route in consideration of the generated line length limiter.

[Effect]

In the wiring route search method of the present invention, when a new wiring route is searched, the parallel wiring length calculation means calculates the parallel wiring length between the searched wiring route and the already routed other wiring routes adjacent to it for each net. At the same time, based on the calculated parallel wiring length, the crosstalk amount calculation means calculates, for each net, the amount of crosstalk that the net for which the wiring route has been newly searched gives to the net connected to the already routed other wiring route, Furthermore, the crosstalk amount determining means takes this calculated amount of crosstalk into account and determines whether or not the amount of crosstalk exceeds a permissible value for the net for which the wiring route has already been determined. If there is a net that is determined to exceed the allowable value by this crosstalk amount determination means, a line length limiter is temporarily generated in the adjacent grid of the wiring route that spans that net, and this occurs. Another wiring route is searched for in place of the newly searched wiring route, taking into consideration the line length limiter set.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the wiring route search method of the present invention. and,
Crosstalk amount calculation means 3, crosstalk amount determination means 4, line length limiter generation step 5, control means 6, output means 7, table update means 8, wiring information storage means 9, and network It is composed of a crosstalk amount table 10, a temporary net crosstalk amount table 11, and a wiring route information storage means 12. Each component has the following functions.

O Wiring information storage means 9 A function to hold information regarding the wiring section of each net and configuration information of the printed circuit board, etc. to be wired.

In this embodiment, the information regarding the line length limiter temporarily generated by the line length limiter generating means 5 is temporarily stored in the wiring information storage means 9.

Oei! , 'Ia Route information storage means 12 Function to hold information related to the searched wiring route.

O-Net Crosstalk Amount Table 10 A function that holds the current amount of crosstalk for each net for which the wiring route has already been determined.

○Temporary net crosstalk amount table 11 A function to temporarily hold, for each net, the amount of crosstalk given by the net currently targeted for wiring search to other nets whose wiring routes have already been determined.

O Wiring route search means 1 A function of searching for a wiring route for unprocessed wiring sections stored in the wiring information storage means 9 and storing the results in the wiring route information storage means 12.

O Parallel wiring length calculation means 2 When a new wiring route is searched, a function of calculating the parallel wiring length between the searched wiring route and other already routed wiring routes adjacent to it for each net.

○Crosstalk amount calculation means 3 Based on the parallel wiring length calculated by the parallel wiring length calculation means 2, the amount of crosstalk given by the net whose wiring route is newly searched this time to the net connected to the already routed other wiring route is calculated for each net. Calculate the amount of temporary net crosstalk table 1
Note that an example of calculating the amount of crosstalk based on the parallel length is to multiply the parallel length by a numerical value called the crosstalk coefficient determined by experiment. be able to.

O Crosstalk amount determination means 4 Adds the current crosstalk amount of each net held in the temporary net crosstalk amount table 11 to the current crosstalk amount of each net held in the net crosstalk amount table 10. However, each time a new wiring route is searched, a function that determines whether the amount of crosstalk exceeds an allowable value for a net for which a wiring route has already been determined.

O-line length limiter generating means 5 A function of temporarily generating a line length limiter on the adjacent grid of the wiring route connected to the net determined by the crosstalk amount determining means 4 to exceed the allowable value.

O control means 6 A function that performs overall control such as starting each of the above-mentioned means.

FIG. 2 is an operation flowchart of the embodiment shown in FIG.
Reference numerals 81 to 319 indicate processing boxes.The operation of this embodiment will be described below with reference to each figure.

After the necessary wiring information is stored in the wiring information storage means 9,
When activated, the control means 6 sets the amount of crosstalk for all nets in the net crosstalk amount table IO to the initial value 0 (Sl), and activates the wiring route search means 1.

When the wiring route search means 1 is activated, it performs the processing in processing boxes 32 to S4 in FIG.
2) If it does not exist, end the process; if it does exist, take out one unprocessed wiring section S3) Search for a distribution wA route for this extracted wiring section (34);
The searched wiring route is stored in the wiring route information storage means 12.

When a new wiring route is searched by the wiring route searching means 1, the parallel wiring length calculating means 2 is activated by the control means 6, and the parallel wiring length calculating means 2 calculates the wiring route found this time by the wiring route searching means 1. , the wiring routes of other components existing in the wiring grid adjacent to the wiring route are checked from the information in the wiring route information storage means 12, and for each (7), the wiring route found this time and the wiring existing in the adjacent wiring grid are determined. The length parallel to the path is determined and this is calculated by the crosstalk amount calculation means 3.
(S5).

The crosstalk amount calculation means 3 calculates the amount of crosstalk for each net based on the parallel length of each net notified from the parallel wire length calculation means 2, and stores this calculated value in the temporary net crosstalk amount table 11. Store (36)
, After that, the crosstalk amount determining means 4 is activated.

When the crosstalk amount determining means 4 is activated, it performs the processing in processing boxes 87 to 310 in FIG. 1.

First, among the nets whose crosstalk amount values are stored in the temporary net crosstalk amount table 11, it is determined whether there are nets that have not yet been checked in the processing box S9, and it is determined whether there are any unprocessed nets. sometimes,
One of the unprocessed nets is extracted in processing box S8, and in the next processing box S9, temporary net crosstalk amount table 1 is created for this extracted net.
1 and the crosstalk amount stored in the net crosstalk amount table 10, and compare this with the allowable crosstalk amount set in advance from the outside. . Then, in processing box S10, the result of the comparison in processing box S9 is determined, and if the allowable crosstalk amount is larger than the sum crosstalk amount determined in processing box S9, no problem will occur, so processing in box S7 is performed. Go back and repeat the same process as described above for the remaining unprocessed nets, and if the sum of the crosstalk amounts found in process box S9 is larger, line length limiter generating means 5 is activated, and then process box S
Return to 7.

When the line length limiter generating means 5 is activated, the processing box S
Regarding the net extracted in step 8, that is, the net that exceeds the allowable crosstalk amount, other nets on the adjacent grids on both sides of the wiring route of that net (7) (excluding the nets searched in processing box 4 this time) are Line length limiters are temporarily generated at regular intervals preset from the outside in empty grids that are not used for wiring routes, etc. (S l 1).

When the crosstalk amount determining means 4 finishes processing all the nets in the temporary net crosstalk amount table 11 (YES in processing box S7), it notifies the control means 6 of the result and ends the operation.

In response to the notification from the crosstalk amount determining means 4, the control means 6 determines that the determination made in the determination box S10 for the current one wiring section taken out in the processing box S3 is based on the amount of crosstalk for the net determined in the processing box S9. The amount of allowable crosstalk is greater than that! ! (NO in processing box 312), the output means 7 is activated to output the wiring route determined in processing box S4 to the outside (317), and the table updating means 8 is activated to output the wiring route obtained in processing box S4. The value for each net in the temporary net crosstalk amount table 11 whose values were stored in S6 is
Net crosstalk amount table 1 that corresponds to that net
0 (S18), and the total crosstalk amount for all nets in the temporary net crosstalk amount table 11 is added to the net crosstalk amount table for the net in the wiring section extracted in processing box S3. It is added to the value of 10 (319), and the wiring route searching means 1 is activated again.

On the other hand, when it is recognized in the judgment box S12 that there is a net exceeding the allowable crosstalk amount from the notification from the crosstalk amount judgment means 4, the current wiring route determined in the processing box S4 is invalidated and the current wiring route determined in the processing box S4 is re-executed. The wiring route searching means 1 is caused to search for a wiring route for the wiring section taken out in the processing box S3 (313). At this time, since the line length limiter is set in the processing box Sll, the wiring route searching means 1 searches for a wiring route while recognizing the line length limiter. The wiring route found as a result of the search is stored in the wiring route information storage means 12 instead of the original wiring route.

When the search for a wiring section in consideration of this line length limiter is completed, the control means 6 deletes the line length limiter generated by the line length limiter generation means 5 (314), and the parallel line length calculation means 2. The crosstalk amount calculation means 3 are activated in that order. In response to this, the parallel wiring length calculating means 2 calculates the processing box S.
In the same manner as in step 5, the parallel length between the wiring route determined in processing box 313 and the wiring route of another net on the adjacent wiring grid is determined for each net (315).
, the crosstalk amount calculation means 3 calculates the crosstalk amount for each net based on the parallel length of each net notified from the parallel wire length calculation means 2 in the same way as in processing box S6, and temporarily uses this calculated value. It is stored in the net crosstalk amount table 11 (316), and then the control means 6
starts the output means 7 to output the wiring route determined by the processing box SL3 to the outside (317), then starts the table update means 8, and outputs the temporary net crosstalk amount whose value is stored in the processing box 316 (317). table 11
The value for each net is added to the value in the net crosstalk amount table 10 to which that net corresponds (318), and the total amount of crosstalk for all nets in the temporary net crosstalk amount table 11 is calculated as follows: It is added to the value in the net-node-crosstalk amount table 10 for the net in the wiring section extracted in processing box S3 (S19), and the wiring route search means 1 is activated again.

〔Effect of the invention〕

As explained above, in the wiring route search method of the present invention, each time a new wiring route is found, it is checked whether the amount of crosstalk exceeds the allowable value, and only if the amount exceeds the allowable value, the line length limiter is set. Since the wiring route is searched again by temporarily causing the crosstalk, it is possible to determine a wiring route that suppresses the amount of crosstalk within the allowable value, and each time a new wiring route is determined, This eliminates the occurrence of many unnecessary bends in the wiring route, which is the case with the conventional method in which a line length limiter is generated at the same time, and improves the wiring efficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is an operational flowchart of the embodiment of the present invention. In the figure, l...Wiring route searching means 2...Parallel wiring length calculating means 3...Crosstalk amount calculating means 4...Crosstalk amount determining means 5...Line length limiter generating means 6. ... Control means 7 ... Output means 8 ... Table updating means 9 ... Wiring information storage means IO ... Net crosstalk amount table 11 ... Temporary net crosstalk amount table 12 ... Wiring route Information storage means

Claims (1)

[Scope of Claims] In a wiring route search method for determining wiring routes for wiring sections to be connected in wiring design for printed wiring boards, ceramic wiring boards, integrated circuits, etc., when searching for a new wiring route, the searched wiring Parallel wiring length calculation means for calculating the parallel wiring length between the route and the existing wiring route adjacent thereto for each net, and searching for the new wiring route based on the parallel wiring length calculated by the parallel wiring length calculation means. a crosstalk amount calculation means that calculates the amount of crosstalk that the added net gives to nets connected to other existing wiring routes for each net, and a new wiring route that takes into account the amount of crosstalk calculated by the crosstalk amount calculation means. crosstalk amount determining means for determining whether the amount of crosstalk exceeds an allowable value for a net for which a wiring route has already been determined each time the wiring route is determined; If there is a net that is determined to be a wire length limiter, a line length limiter is temporarily generated in the adjacent grid of the wiring route related to the net, and the new search is performed in consideration of the generated line length limiter. A wiring route search method characterized in that a wiring route is searched for in place of a wiring route that has been selected.