JP4676995B2 - Design support program, recording medium storing the program, design support apparatus, and design support method - Google Patents

Description

  The present invention relates to a design support program that supports the design of an LSI or a printed circuit board, a recording medium that records the program, a design support apparatus, and a design support method.

  In designing an analog circuit or printed circuit board wiring in LSI design, in order to satisfy the specified circuit characteristics (R, C), and to reduce the influence of characteristic fluctuations due to variations, wiring restrictions are given in units of microns. . For example, in a differential circuit, equal-length wiring restrictions are given to a plurality of wirings.

  In general, since it is difficult to automate wiring satisfying such wiring constraints, each wiring pattern is determined by repeating trial and error by hand. For this reason, the work load and work time for the wiring work increase, which causes a longer design period.

  Therefore, as a method for automating the wiring work, in Patent Document 1 below, a wiring route having the maximum wiring length is extracted from a plurality of existing wiring circuit data, and the wiring length of another wiring route different from the wiring route is described. A method is described in which equal-length wiring is performed by changing other wiring paths so as to achieve the maximum wiring length.

  Also, in Patent Document 2 below, a predetermined area is created based on all connection point positions of connection points for performing star-type designated length wiring, and via-point candidates are generated in the area under predetermined conditions. Then, for the generated via-point candidates, search for a via-point from among the via-point candidates that satisfy the wiring conditions when all the connection points perform star-type specified-length wiring, and specify the specified-length wiring from the via-point to the pin The method of performing is described.

JP-A 63-271661 Japanese Patent Laid-Open No. 08-36596

  However, the conventional techniques described in Patent Documents 1 and 2 described above have a problem that a complicated wiring prohibited area (area where an obstacle exists) cannot be handled. This is because if the number of obstacles (transistors, wiring, vias, etc.) on the wiring area increases and the design rules become complicated, it is determined whether or not a wiring satisfying the wiring constraints can be realized in the given wiring area. Because it becomes difficult.

  For this reason, when handling complicated wiring prohibited areas, the result of repeated trial and error by hand is that the work load and work time for the wiring work still increase, which in turn leads to a prolonged design period. There is.

  In order to eliminate the above-described problems caused by the prior art, the present invention reduces the work load and shortens the design period by automating a wiring having a wiring length that satisfies the specified circuit characteristics in a predetermined wiring area. An object of the present invention is to provide a design support program, a recording medium storing the program, a design support apparatus, and a design support method.

  In order to solve the above-described problems and achieve the object, the design support program, the recording medium storing the program, the design support apparatus, and the design support method are provided in a first and second arrangement arranged in a predetermined wiring area. The circuit searches for a wiring path connecting the terminals of the circuit and a circuit that is not connected to the wiring path in the predetermined wiring region, and combines the wiring path length of the searched wiring path with the wiring path length of the circuit. It is necessary to calculate the wiring path length, determine whether the calculated wiring path length is equal to or longer than the wiring path length satisfying the specified circuit characteristics, and output the determined determination result.

  According to the design support program, the recording medium on which the program is recorded, the design support apparatus, and the design support method, instead of the longest wiring path between terminals that are difficult to search, an arbitrary wiring path and circuit that connect the terminals Can be used to determine the feasibility of a wiring path length that satisfies the specified circuit characteristics in a predetermined wiring area.

  Further, in the design support program, the recording medium storing the program, the design support apparatus, and the design support method, when it is determined that the wiring path length exceeds the specified circuit characteristic, a part of the wiring path and the circulation The longest wiring path from the first terminal to the second terminal after passing through a part of the path may be searched, and the searched longest wiring path may be output.

  According to the design support program, the recording medium on which the program is recorded, the design support apparatus, and the design support method, the wiring path between the terminals and the cyclic circuit are connected at four connection points while maintaining the wiring path length to the maximum. By reconnecting, the longest wiring path between terminals can be searched.

  Further, in the design support program, the recording medium storing the program, the design support apparatus, and the design support method, the wiring path length of the searched longest wiring path is calculated, and the calculated wiring path length of the longest wiring path is It may be determined whether or not the wiring path length satisfies the circuit characteristics of the specification.

  According to the design support program, the recording medium on which the program is recorded, the design support apparatus, and the design support method, the specification in the predetermined wiring region is determined by re-determination using the wiring route length of the searched longest wiring route. Therefore, it is possible to more accurately determine the feasibility of the wiring path length that satisfies the circuit characteristics.

  Further, in the design support program, the recording medium storing the program, the design support apparatus, and the design support method, a difference between the wiring path length of the longest wiring path and the wiring path length satisfying the circuit characteristics of the specification is previously determined. It is determined whether or not it is within the set allowable range. If it is determined that it is out of the allowable range, the longest wiring path is changed to be the wiring path length within the allowable range, and the changed longest wiring after the change The route may be output.

  According to the design support program, the recording medium storing the program, the design support apparatus, and the design support method, it is possible to realize wiring having a wiring path length that satisfies the circuit characteristics of the specification in a predetermined wiring region.

  In the design support program, the recording medium storing the program, the design support apparatus, and the design support method, the predetermined wiring area includes a first wiring area that does not include an obstacle, and a second that includes an obstacle. It is good also as performing a search process, a calculation process, and a determination process for every divided | segmented 1st and 2nd wiring area | region.

  According to the design support program, the recording medium on which the program is recorded, the design support apparatus, and the design support method, by dividing a predetermined wiring area and reducing the target wiring area, the actual longest wiring path It is possible to reduce an error between the wiring path length and the wiring path length obtained by combining the wiring path length of the wiring path between the terminals and the wiring path length of the circuit.

  In addition, in the design support program, the recording medium storing the program, the design support apparatus, and the design support method, a result of execution of search processing, calculation processing, and determination processing for each of the first and second wiring regions , Passing through a part of the first longest wiring path in the first wiring area and a part of the second longest wiring path in the second wiring area, from the first terminal to the second It is also possible to search for the longest wiring route until the terminal is reached.

  According to the design support program, the recording medium on which the program is recorded, the design support apparatus, and the design support method, the circuit characteristics of the specifications in a predetermined wiring region are satisfied by accurately searching for the longest wiring path between terminals. The feasibility of the wiring path length can be accurately determined.

  According to the design support program, the recording medium storing the program, the design support apparatus, and the design support method, by automating the wiring with the wiring length satisfying the circuit characteristics of the specification within the predetermined wiring area, There is an effect that reduction and shortening of the design period can be achieved.

  Exemplary embodiments of a design support program, a recording medium recording the program, a design support apparatus, and a design support method will be described below in detail with reference to the accompanying drawings.

(Hardware configuration of design support device)
First, the hardware configuration of the design support apparatus according to the present embodiment will be described. FIG. 1 is an explanatory diagram illustrating a hardware configuration of the design support apparatus according to the present embodiment.

  In FIG. 1, a design support apparatus 100 includes a computer main body 110, an input apparatus 120, and an output apparatus 130. The design support apparatus 100 is connected to a network 140 such as a LAN, WAN, or the Internet via a router or a modem (not shown). Connectable.

  The computer main body 110 has a CPU, a memory, and an interface. The CPU governs overall control of the design support apparatus 100. The memory is composed of ROM, RAM, HD, optical disk 111, and flash memory. The memory is used as a work area for the CPU.

  Various programs are stored in the memory, and loaded according to instructions from the CPU. Data read / write of the HD and the optical disk 111 is controlled by a disk drive. The optical disk 111 and the flash memory are detachable from the computer main body 110. The interface controls input from the input device 120, output to the output device 130, and transmission / reception with respect to the network 140.

  The input device 120 includes a keyboard 121, a mouse 122, a scanner 123, and the like. The keyboard 121 includes keys for inputting characters, numbers, various instructions, and the like, and inputs data. Further, it may be a touch panel type. The mouse 122 performs cursor movement, range selection, window movement, size change, and the like. The scanner 123 optically reads an image. The read image is captured as image data and stored in a memory in the computer main body 110. Note that the scanner 123 may have an OCR function.

  The output device 130 includes a display 131, a speaker 132, a printer 133, and the like. The display 131 displays data such as a document, an image, and function information as well as a cursor, an icon, or a tool box. The speaker 132 outputs sounds such as sound effects and reading sounds. The printer 133 prints image data and document data.

(Outline of this embodiment)
Next, an outline of the present embodiment will be described. In the present embodiment, in the layout processing of an LSI or a printed circuit board, wiring having a wiring length that satisfies the circuit characteristics of a specification within a predetermined wiring area is automated, thereby reducing the work load and shortening the design period. .

  In designing an analog circuit or printed circuit board wiring in LSI design, wiring constraints (specified length, equal length wiring, etc.) in units of microns are given in order to satisfy the specified circuit characteristics. However, the high integration of LSIs and printed circuit boards increases the number of obstacles (transistors, wiring, vias, etc.) on the wiring region and complicates the design rules.

  For this reason, it becomes difficult to search for the longest path between terminals in a wiring area allocated for wiring formation between terminals, and it is difficult to determine the feasibility of wiring satisfying the specified circuit characteristics in the wiring area. It has become. Therefore, a method for efficiently and effectively determining the feasibility of wiring satisfying the specified circuit characteristics in a predetermined wiring region is proposed.

  First, instead of the longest path between terminals that are difficult to search, a wiring path between terminals including a circuit is searched as a longest path candidate. When the wiring length of the longest path candidate is equal to or longer than the wiring length satisfying the specified circuit characteristics, it is determined that the wiring satisfying the specified circuit characteristics can be realized. This utilizes the characteristic that the wiring length of the wiring path between the terminals including the circuit is equal to or longer than the wiring length of the wiring path between the terminals not including the circuit.

  In other words, if the wiring length of the wiring path between the terminals including the circuit is less than the wiring length satisfying the specified circuit characteristics, it means that the wiring satisfying the wiring constraint cannot be realized. When it is determined that the wiring satisfying the circuit characteristics of the specification is not feasible, for example, correction is made such as returning to the upstream process and changing the arrangement position of each terminal.

  On the other hand, if it is determined that wiring that satisfies the specified circuit characteristics is feasible, the wiring path including the circuit is automatically corrected according to the wiring length that satisfies the specified circuit characteristics, and wiring restrictions are imposed. Realize wiring between terminals to satisfy. As a result, it is possible to handle a wiring area including a complicated wiring prohibition area (obstacle), and it is possible to automate a wiring having a wiring length that satisfies the specified circuit characteristics.

(Specific example of wiring area)
Here, a specific example of a wiring area allocated to form a wiring path between terminals will be described. FIG. 2 is an explanatory diagram showing a specific example of the wiring area. In FIG. 2, a wiring region 200 is a wiring region allocated to form a wiring path that connects a source S (first terminal) and a target T (second terminal).

  The wiring area 200 is divided into nine grids divided into a grid pattern. Labels R1 to R9 for identifying each grid are assigned to the grid. In the wiring region 200, grids (hatched portions in FIG. 2) to which labels R8 and R9 are given indicate wiring prohibited regions in which obstacles such as transistors, wirings, and vias are arranged. The grid size (grid size) for dividing the wiring region 200 is determined by the wiring process.

(Data structure of wiring information)
Next, the data structure of the wiring information related to the wiring area shown in FIG. 2 will be described. FIG. 3 is an explanatory diagram showing the data structure of the wiring information. In FIG. 3, the wiring information 300 includes information regarding the number of grids, the source S, the target T, the wiring prohibited area, and the coordinate position of each grid.

  The number of grids represents the number of grids in the X direction and Y direction of the wiring region 200 (see FIG. 2). The source S represents the arrangement position of the start point terminal. Here, the start point terminal is arranged on the grid of the label R7. The target T represents the arrangement position of the end point terminal. Here, the end point terminals are arranged on the grid of the label R3.

  The wiring prohibition area represents a grid in which obstacles such as transistors, wirings, and vias are arranged and a new wiring cannot be formed. Here, the grids of the labels R8 and R9 are wiring prohibited areas. Further, the wiring information 300 includes coordinate data (for example, the coordinate table 400 shown in FIG. 4) for recognizing the coordinate position of each grid.

  FIG. 4 is an explanatory diagram showing the contents stored in the coordinate table. In FIG. 4, a coordinate table 400 stores information on label names and coordinate positions for each grid. By referring to the coordinate table 400, the coordinate position of each grid can be recognized. For example, the coordinate position of the grid of the label R1 is (X, Y) = (1, 1).

(Functional configuration of design support device)
Next, a functional configuration of the design support apparatus 100 will be described. FIG. 5 is a block diagram illustrating a functional configuration of the design support apparatus. In FIG. 5, the design support apparatus 100 includes a search unit 501, a calculation unit 502, a determination unit 503, an output unit 504, a change unit 505, and a division unit 506.

  Each of these functions 501 to 506 can be realized by causing the CPU to execute a program related to the functions 501 to 506 stored in the storage unit of the design support apparatus 100 or by using an input / output I / F. it can. Output data from each function 501 to 506 is held in the storage unit. Further, the connection destination function indicated by the arrow in FIG. 5 reads output data from the connection source function from the storage unit and causes the CPU to execute a program related to the function.

  First, the search unit 501 has a function of searching for a wiring path that connects the first and second terminals arranged in a predetermined wiring area and a circuit that is not connected to the wiring path in the predetermined wiring area. Have The predetermined wiring area is a wiring area assigned for every two terminals in the circuit to be designed. For example, a predetermined wiring area can be automatically allocated to the first and second terminals by executing a layout tool. The circuit is a loop-shaped wiring path. This forward circuit is formed in the remaining area of the predetermined wiring area except for the area where the wiring path connecting the first and second terminals is formed.

  Specifically, for example, the search unit 501 includes wiring area information regarding a predetermined wiring area, wiring prohibition information representing a wiring prohibition area within the wiring area, and connection terminal information regarding the first and second terminals. Based on this, a search is made for a wiring route and a circuit that connect the first and second terminals. For example, the wiring information 300 shown in FIG. 3 can be used as the wiring area information, the wiring prohibition information, and the connection terminal information. The wiring information 300 may be directly input to the design support apparatus 100, or may be acquired by acquisition from an external device (not shown) or extraction from a database or library (not shown).

  Here, a specific example of the first search process for searching for the wiring route and the circuit connecting the first and second terminals by the search unit 501 will be described. FIG. 6 is an explanatory diagram showing an overview of the first search process. Here, a search is made for a wiring path connecting the source S and the target T in the wiring area 600 and a circuit in the wiring area 600 that is not connected to the wiring path.

  First, a graph 610 is created in which each grid in the wiring region 600 is noded and variables x1 to x12 are assigned to each edge connecting the nodes. The arrangement position of each node in the graph 610 corresponds to the arrangement position of each grid in the wiring region 600. For example, the node e1 corresponds to the grid on which the source S is arranged.

  Hereinafter, using the graph 610, a wiring route and a route from the source S to the target T are searched. As a precondition, in the graph 610, it is not possible to turn back, and the search is terminated when the same grid is reached twice.

  Specifically, the longest path search problem including a cyclic route is modeled as a linear programming problem. More specifically, the longest path search problem including a circular circuit is modeled as an integer programming problem, and the integer programming problem is relaxed to a linear programming problem. First, when the integer programming problem is formulated, the objective function becomes the following expression (1), and the constraint expressions become the following expressions (2) to (5). Here, di is the distance of section i. Moreover, xi = 1 means that the section i is passed, and xi = 0 means that the section i is not passed.

    max. Σ {di · xi | i is a section} (1)

    Σ {ei | i is a terminal node} = 2 (2)

    bi∈ {0, 2} (where bi is an arbitrary branch node) (3)

    eiε {1} (where ei is two start and end nodes) (4)

    xi∈ {0, 1} (where xi is an arbitrary edge) (5)

  Next, this integer programming problem is relaxed to a linear programming problem. Specifically, the above constraint expression is expressed by a linear programming constraint. Here, taking the representative node (start point end point node, 3 branch node, 4 branch node) in the graph 610 as an example, a constraint expression in which the above expressions (3) and (5) are expressed by a linear programming constraint will be described.

  First, taking the node e1 (start node) in the graph 610 as an example, the constraint equation is “+ x1 + x7 = 1, 0 ≦ x1 ≦ 1, 0 ≦ x7 ≦ 1”. Next, taking the node e2 (end point node) as an example, the constraint equation is “+ x6 + x12 = 1, 0 ≦ x6 ≦ 1, 0 ≦ x12 ≦ 1”.

  Next, taking the node b3 (three branches) as an example, “−x3 + x7 + x8 ≧ 0, + x3−x7 + x8 ≧ 0, + x3 + x7−x8 ≧ 0, + x3 + x7 + x8 ≦ 2, 0 ≦ x3 ≦ 1, 0 ≦ x7 ≦ 1,0 ≦ x8 ≦ 1 ”.

  Next, taking the node b4 (four branches) as an example, “−x3 + x4 + x9 + x10 ≧ 0, + x3−x4 + x9 + x10 ≧ 0, + x3 + x4−x9 + x10 ≧ 0, + x3 + x4 + x9−x10 ≧ 0, + x3 + x4 + x9 + x10 ≦ 2, 0 ≦ x3 ≦ 1, 0. ≦ x4 ≦ 1, 0 ≦ x9 ≦ 1, 0 ≦ x10 ≦ 1 ”.

  Thereafter, the objective function shown in the above equation (1) and the constraint expression expressed by the linear programming constraint for each node in the graph 610 are input to the linear programming solver, thereby reaching the target T from the source S. It is possible to obtain the longest route including the route to the end. Note that each variable does not necessarily converge to 0 or 1 because it has been relaxed to a linear programming problem. For this reason, here, a variable having an intermediate value between 0 and 1 is corrected to 0 or 1 so as to be connected to a nearby wiring.

  Here, a specific example of the search result of the first search process will be described. FIG. 7 is an explanatory diagram illustrating a specific example of a search result of the first search process. In FIG. 7, the wiring region 600 shows a wiring path 710 and a circuit 720 that connect the source S and the target T, which are search results of the first search process.

  Returning to the description of FIG. 5, the calculation unit 502 has a function of calculating a wiring route length obtained by combining the wiring route length of the wiring route searched by the search unit 501 and the wiring route length of the circuit. Specifically, for example, the wiring path and the number of grids through which the circuit passes may be used as the wiring path length, and the value obtained using the above equation (1) may be used as the wiring path length. Good.

  The determination unit 503 has a function of determining whether or not the wiring path length calculated by the calculation unit 502 is equal to or longer than the wiring path length satisfying the specified circuit characteristics. The wiring path length satisfying the circuit characteristics of the specification is, for example, a wiring restriction defined as the specification of the circuit to be designed, and is a specific wiring path length. The wiring path length satisfying the specified circuit characteristics is stored in a storage unit such as a ROM or a RAM, for example.

  The output unit 504 has a function of outputting the determination result determined by the determination unit 503. For example, when it is determined that the wiring path length satisfying the specified circuit characteristics is less than the wiring path length that satisfies the specified circuit characteristics, an error message indicating that the wiring path length that satisfies the specified circuit characteristics cannot be satisfied is output. Also good. Note that the output format of the output unit 504 may be any of screen display on the display 131, print output on the printer 133, data output (save) to the memory, and transmission to an external computer device.

  By confirming this error message, the designer can recognize that the wiring satisfying the wiring constraint cannot be realized in the wiring area allocated to the first and second terminals. Thereby, it is possible to appropriately and quickly take measures such as returning to the upstream process and changing the arrangement positions of the first and second terminals.

  When the determination unit 503 determines that the length is equal to or longer than the wiring path length, the searching unit 501 passes through a part of the wiring path and a part of the circuit and reaches the second terminal from the first terminal. Has the function of searching for the longest wiring route. Specifically, a single longest wiring route that maintains the maximum wiring route length is searched by switching the wiring route and the circuit at four connection points.

  Here, a specific example of the second search process for searching for the longest wiring route by the search unit 501 will be described. Here, the search result shown in FIG. 7 will be described as an example. FIG. 8 is an explanatory diagram showing an outline of the second search process. When searching for the longest wiring route, a turnout switch graph (hereinafter referred to as “Ts graph”) 800 shown in FIG. 8 is created.

  The Ts graph 800 is a graph expressing connectable points when the wiring route 710 and the circuit 720 are switched. Specifically, first, a boundary line between the wiring path 710 and the circuit 720 is detected from the boundary lines that divide the wiring region 600. For example, for each grid from the source S of the wiring path 710 to the target T, a boundary line with the circuit 720 is detected. Each time a boundary line is detected, an edge ID is assigned to the boundary line.

  Here, taking a grid in which the source S is arranged as an example, a boundary line 810 with the circuit 720 is detected, and an edge a is assigned to the boundary line 810. Thus, whenever a boundary line is detected, an edge ID (edges a to d in FIG. 8) is assigned, whereby the boundary line between the wiring path 710 and the circuit 720 can be recognized.

  Thereafter, a Ts graph 800 in which the wiring path 710, the circuit 720, and the edges a to d are nodeized is created. Specifically, a Ts graph 800 is created in which a node N1 representing a wiring path 710 and a node N2 representing a circuit 720 are connected via nodes Na to Nd representing edges a to d.

  Next, the origin of the wiring path 710 and the circuit 720 is set. The position of the origin can be set arbitrarily. Here, the origin of the wiring path 710 is set to the source S (hereinafter referred to as “origin S”), and the origin of the circuit 720 is set to the point A (hereinafter referred to as “origin A”).

  Further, the distance from the origin S to the edges a to d is obtained by following the route of the wiring route 710 and set to each branch connecting the nodes. For example, since the distance from the origin S to the edge a is “0”, “0” is set to the branch connecting the node N1 and the node Na. Further, since the distance from the origin S to the edge d is “4”, “4” is set to the branch connecting the node N1 and the node Nd.

  Similarly, the distance from the origin A to the edges a to d is obtained by following the route of the circuit 720, and set to each branch connecting the nodes. At this time, the route of the circuit 720 is traced clockwise. For example, since the distance from the origin A to the edge a is “1”, “1” is set to the branch connecting the node N2 and the node Na. Further, since the distance from the origin A to the edge d is “3”, “3” is set to the branch connecting the node N2 and the node Nd.

  Here, the data structure of specific graph information representing the Ts graph 800 will be described. 9 and 10 are explanatory diagrams showing the data structure of the graph information. In FIG. 9, the graph information 900 includes information regarding the node name, flag, and node type for each of the nodes N1, N2, and Na to Nd. For example, the node N1 is a wiring route whose flag is set to ON. Detailed description regarding the flag will be described later.

  In FIG. 10, the graph information 1000 includes information regarding the distance from the nodes Na to Nd representing the boundary line for each of the nodes N1 and N2. By referring to the graph information 1000, the distance between nodes can be specified. The Ts graph 800 described above can be expressed by the graph information 900 and 1000 shown in FIGS. 9 and 10.

  Next, using the graph information 900 and 1000, the longest wiring path from the source S to the target T through a part of the wiring path 710 and a part of the circuit 720 is searched. First, the flags of all nodes in the graph information 900 are set to OFF. Next, the flag of the node N1 including the source S and the target T is set to ON.

  Thereafter, using the distance between the nodes included in the graph information 1000, when a transition is made from the node N1 to the node N2 to the node N1, a return route with the smallest detour is searched. Specifically, from among the nodes Na to Nd, two nodes Na to Nd serving as a connection point through which the transition from the node N1 to the node N2 and a connection point through which the transition from the node N2 to the node N1 are performed. Is selected, and the cost in the case of transition from node N1 → node N2 → node N1 is calculated.

  For example, assuming that the nodes Na and Nb are selected from the nodes Na to Nd, the cost for transitioning from the node N1 → the node Na → the node N2 → the node Nb → the node N1 is calculated. Specifically, from the value (1) obtained by adding the distance (0) between N1 and Na and the distance (1) between N2 and Na, the distance (2) between N2 and Nb and the distance between N1 and Nb. A value (−2) obtained by subtracting a value (3) obtained by adding (1) is defined as a cost.

  Specifically, the value (1) obtained by adding the distance (0) between N1 and Na and the distance (1) between N2 and Na increases when the wiring route 710 and the circuit 720 are switched. Wiring path length. Further, the value (3) obtained by adding the distance (2) between N2 and Nb and the distance (1) between N1 and Nb is a wiring path length that decreases when the wiring path 710 and the circuit 720 are switched. It is.

  This cost is obtained for all the combinations “Na-Nb, Na-Nc, Na-Nd, Nb-Nc, Nb-Nd, Nc-Nd” as connection points, and the cost is maximum (the decrease in wiring path length is minimum). ) Is determined as a combination of connection points. Here, the combination of “Na—Nb” is the maximum cost. As a result, according to the transition of the node N1, the node Na, the node N2, the node Nb, and the node N1, the wiring route that follows the grid in the wiring region 600 is determined as the longest wiring route.

  Here, a specific example of the search result of the second search process will be described. FIG. 11 is an explanatory diagram illustrating a specific example of a search result of the second search process. In FIG. 11, reference numeral 1100 denotes the longest wiring path (node N1 → node Na → node N2 described above) from the source S to the target T through a part of the wiring path 710 and a part of the circuit 720. → node Nb → node N1).

  When there is another tour circuit adjacent to the tour circuit 720, the longest wiring route 1100 is searched, and as a result, it passes through a part of the longest wiring route 1100 and a part of the other tour circuit. Thus, the longest wiring route from the source S to the target T is searched.

  FIG. 12 is an explanatory diagram illustrating an example of the longest wiring path that passes through a part of a plurality of circuits. In FIG. 12, (1) shows a wiring path H that connects the source S and the target T and the circular circuits J1 to Jn. In this case, the second search process by the search unit 501 is executed in order from the circuit J1 adjacent to the wiring path H to search for the longest wiring path from the source S to the target T.

  As a result, as shown in (2), the process from passing through part of the wiring path H and part of the circuits J1 to Jn (J'1 to J'n) until reaching the target T from the source S. The longest wiring route I is searched. At this time, by setting the flags of the tours J1 to Jn (corresponding to the flag of the graph information 900) for which the search has been completed to ON, the unsearched tours J1 to Jn can be recognized.

  Returning to the description of FIG. 5, the output unit 504 has a function of outputting the longest wiring path searched by the search unit 501. Specifically, for example, a search result representing a connection relation of labels specifying a grid through which the longest wiring route passes may be output. Here, an output example output by the output unit 504 will be described.

  FIG. 13 is an explanatory diagram of an example of search result output. In FIG. 13, a search result 1300 representing the longest wiring path 1100 (see FIG. 11) is shown. The search result 1300 has label information that identifies a grid having a connection relationship.

  Thereby, the longest wiring path 1100 can be specified as a wiring path that passes through R7 → R8 → R9 → R6 → R5 → R4 → R1 → R2 → R3. Note that the coordinate positions of the labels R1 to R9 can be recognized by referring to a coordinate table included in the wiring information of the wiring area.

  The calculation unit 502 has a function of calculating the wiring route length of the longest wiring route searched by the search unit 501. The determination unit 503 has a function of determining whether or not the wiring path length of the longest wiring path calculated by the calculation unit 502 is equal to or longer than the wiring path length satisfying the specified circuit characteristics.

  That is, as a result of searching for a single longest wiring route by switching the wiring route and the circuit, it is determined whether or not a wiring route length satisfying the specified circuit characteristics can be realized. Here, when it is determined that the wiring path length is less than the specified circuit characteristic, for example, the error message described above may be output.

  The determination unit 503 may determine whether the difference between the wiring path length of the longest wiring path and the wiring path length satisfying the specified circuit characteristics is within a preset allowable range. Specifically, as the wiring constraint, an error that does not completely match the designated wiring path length but satisfies the circuit characteristics is set as an allowable range. For example, the allowable range can be arbitrarily set by the user operating the input device 120 such as the keyboard 121 and the mouse 122 shown in FIG.

  In addition, the changing unit 505 has a function of changing the longest wiring path so as to become the wiring path length within the allowable range when the determining unit 503 determines that it is outside the allowable range. Specifically, for example, the wiring path length of the longest wiring path I is adjusted by separating J′1 to J′n, which are a part of the longest wiring path I shown in FIG. It is good to do.

  Furthermore, for example, when the wiring path length of the longest wiring path I becomes shorter than the wiring path length satisfying the specified circuit characteristics as a result of cutting off the terminal J′n, a part of the longest wiring path I is The wiring path length may be adjusted by making a detour in an empty area within a predetermined wiring area. The output unit 504 has a function of outputting the changed longest wiring path changed by the changing unit 505.

  The dividing unit 506 has a function of dividing a predetermined wiring area into a first wiring area that does not include an obstacle and a second wiring area that includes an obstacle. This is performed in order to reduce an error between the wiring path length obtained by combining the wiring path length of the wiring path and the wiring path length of the circuit and the actual wiring path length of the longest wiring path. This is particularly effective when handling a large wiring area.

  Specifically, for example, the dividing unit 506 sets a cut line along a boundary line that divides a predetermined wiring area based on the wiring information 300, and thereby includes a first wiring area that does not include an obstacle, Dividing into a second wiring region including an obstacle. At this time, for example, the predetermined wiring area may be divided so that the area not including the obstacle (wiring prohibited area) is as large as possible.

  The cut line setting position may be set, for example, at a position one grid or more away from the wiring prohibited area. When the cut line must be set at a position in contact with the wiring prohibited area, it is possible to avoid a situation in which a routable area exists between the two wiring prohibited areas.

  Note that the cut line information indicating the set position of the cut line on the wiring area may be expressed by, for example, the coordinate position of the grid. The cut line information is stored in the storage unit as a result of being divided by the dividing unit 506. Then, the first and second wiring regions can be recognized by reading the cut line information from the storage unit.

  In addition, when the predetermined wiring area is divided into the first and second wiring areas by the dividing unit 506, the search unit 501, the calculation unit 502, and the determination unit 503, for each of the first and second wiring areas, Search processing, calculation processing, and determination processing will be executed. Here, a flow of a series of processes when the predetermined wiring area is divided into the first and second wiring areas will be described.

  FIG. 14 is an explanatory diagram showing a flow of a series of processes at the time of division. In FIG. 14, a wiring region 1400 is divided into a first wiring region 1410 and a second wiring region 1420 by a cut line C. In addition, the wiring path 1430 has been searched for in the first wiring area 1410 and the circuit 1440 has been searched for in the second wiring area 1420.

  Here, the wireable regions R15, R17 exist between the wire prohibited regions (labels R16, R17, R19) in contact with the cut line C. In this case, the wiring path 1430 and the circuit 1440 are connected by treating these routable areas R15 and R17 as virtual terminals V1 and V2. As a result, the wiring route 1450 and the circuit routes 1460 and 1470 are searched.

  Finally, the longest wiring path 1480 from the source S to the target T through the part of the wiring path 1450, the part of the circuit 1460, and the part of the circuit 1470 is searched. Note that as a result of searching for the longest wiring path 1480, the changing unit 505 may change the longest wiring path 1480 so as to have a wiring path length that satisfies the circuit characteristics of the specification.

(Design support procedure of design support device)
Next, a design support processing procedure of the design support apparatus 100 according to the present embodiment will be described. FIG. 15 is a flowchart illustrating an example of a design support processing procedure of the design support apparatus. In the flowchart of FIG. 15, it is first determined whether or not wiring information related to a predetermined wiring area has been input (step S1501).

  Here, after waiting for the input of the wiring information (step S1501: No), if it is input (step S1501: Yes), the search unit 501 causes the first and second lines arranged in the predetermined wiring area. A first search process is performed to search for a wiring path that connects the terminals and a circuit that is in a predetermined wiring area and is not connected to the wiring path (step S1502).

  After that, the calculation unit 502 calculates a wiring path length that is the sum of the wiring path length of the wiring path searched in step S1502 and the wiring path length of the circuit (step S1503). Then, the determination unit 503 determines whether or not the wiring path length calculated in step S1503 is equal to or longer than the wiring path length satisfying the specified circuit characteristics (step S1504).

  Here, when the length is equal to or longer than the wiring path length satisfying the circuit characteristics of the specification (step S1504: Yes), the search unit 501 passes a part of the wiring path and a part of the circuit and starts from the first terminal. A second search process for searching for the longest wiring route to reach the second terminal is executed (step S1505).

  Thereafter, the calculation unit 502 calculates the wiring path length of the longest wiring path searched in step S1505 (step S1506). Then, the determination unit 503 determines whether or not the wiring path length calculated in step S1506 is equal to or longer than the wiring path length satisfying the specified circuit characteristics (step S1507).

  If the length is equal to or longer than the wiring path length satisfying the specification circuit characteristics (step S1507: Yes), the determination unit 503 makes a difference between the wiring path length of the longest wiring path and the wiring path length satisfying the specification circuit characteristics. Is determined to be within a preset allowable range (step S1508).

  Here, when it is outside the allowable range (step S1508: No), the changing unit 505 changes the longest wiring path so as to become the wiring path length within the allowable range (step S1509), and returns to step S1508. On the other hand, if it is within the allowable range (step S1508: Yes), the output unit 504 outputs the longest wiring path (step S1510), and the series of processes according to this flowchart ends.

  If the wiring path length is shorter than the wiring path length in step S1504 (step S1504: No), or if the wiring path length is shorter than the wiring path length in step S1507 (step S1507: No), the output circuit 504 changes the circuit characteristics of the specification. An error message indicating that the wiring path length to be satisfied cannot be satisfied is output (step S1511), and the series of processing according to this flowchart is terminated.

  Next, a specific processing procedure of the first search process in step S1502 shown in FIG. 15 will be described. FIG. 16 is a flowchart illustrating an example of a specific processing procedure of the first search process. This is an example in which the longest path search problem including a cyclic route is modeled as a linear programming problem.

  In the flowchart of FIG. 16, first, a graph is created in which each grid in a predetermined wiring region is noded and variables are assigned to the edges connecting the nodes (step S1601). Thereafter, the objective function and the constraint equation are obtained by modeling the longest path search problem including the traveling circuit into a linear programming problem (step S1602).

  Then, by inputting the objective function and the constraint equation obtained in step S1602 to the linear programming solver (step S1603), a wiring path connecting the first and second terminals arranged in the predetermined wiring area, and a predetermined Is determined in step S1604, and the process goes to step S1503 shown in FIG.

  Next, a specific processing procedure of the second search process in step S1505 shown in FIG. 15 will be described. FIG. 17 is a flowchart illustrating an example of a specific processing procedure of the second search process. This is an example of searching for the longest wiring route using a Ts graph (for example, Ts graph 800).

  In the flowchart of FIG. 17, first, a Ts graph is created in which connectable points are expressed when the wiring path connecting the first and second terminals and the circuit are switched (step S1701). After that, using the Ts graph created in step S1701, the cost for each combination of connection points through which transition is made between the node representing the wiring path and the node representing the circuit is calculated (step S1702). ).

  Then, based on the cost for each combination calculated in step S1702, the longest wiring path from the first terminal to the second terminal through a part of the wiring path and a part of the circuit Is determined (step S1703), and the process proceeds to step S1506 shown in FIG.

  When a plurality of tours are searched in the predetermined wiring area in step S1502 shown in FIG. 15, the wiring route connecting the first and second terminals until there is no unsearched tour Steps S <b> 1701 to S <b> 1703 are repeatedly executed in order from the adjacent circuit.

  As described above, according to the present embodiment, instead of the longest wiring path between terminals that are difficult to search, the longest wiring path that combines an arbitrary wiring path between terminals that are relatively easy to search and a cyclic circuit. Candidates can be used to determine the feasibility of a wiring path length that satisfies the specified circuit characteristics in a predetermined wiring region.

  When the wiring path length satisfying the specified circuit characteristics can be realized, the longest wiring path between the terminals can be searched by using an arbitrary wiring path between the terminals and the circuit. Furthermore, by automatically correcting the longest wiring path according to the wiring path length satisfying the specified circuit characteristics, it is possible to realize wiring having a wiring path length satisfying the specified circuit characteristics in a predetermined wiring region.

  Further, by dividing a predetermined wiring area to reduce the target wiring area, an error between the actual wiring path length of the longest wiring path and the wiring path length of the longest wiring path candidate can be reduced. As a result, the longest wiring path between the terminals can be searched with high accuracy, and the feasibility of the wiring path length satisfying the specified circuit characteristics in the predetermined wiring region can be accurately determined.

  In this way, by performing appropriate wiring satisfying the circuit characteristics of the specification, it is possible to reduce useless wiring resources and reduce the size of the circuit to be designed. Furthermore, by automating wiring having a wiring length that satisfies the circuit characteristics of the specification in a predetermined wiring region, it is possible to reduce the work burden and shorten the design period.

  The design support method described in the present embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. This program is recorded on a computer-readable recording medium such as a hard disk, a flexible disk, a CD-ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer. The program may be a transmission medium that can be distributed via a network such as the Internet.

  In addition, the design support apparatus 100 described in the present embodiment includes an application-specific IC (hereinafter simply referred to as “ASIC”) such as a standard cell or a structured ASIC (Application Specific Integrated Circuit), or a PLD (Programmable) such as an FPGA. It can also be realized by Logic Device). Specifically, for example, the design support apparatus 100 is manufactured by defining the functions 501 to 506 of the above-described design support apparatus 100 by HDL description, logically synthesizing the HDL description and giving it to the ASIC or PLD. Can do.

It is explanatory drawing which shows the hardware constitutions of the design support apparatus concerning this Embodiment. It is explanatory drawing which shows the specific example of a wiring area | region. It is explanatory drawing which shows the data structure of wiring information. It is explanatory drawing which shows the memory content of a coordinate table. It is a block diagram which shows the functional structure of a design support apparatus. It is explanatory drawing which shows the outline | summary of a 1st search process. It is explanatory drawing which shows the specific example of the search result of a 1st search process. It is explanatory drawing which shows the outline | summary of a 2nd search process. It is explanatory drawing (the 1) which shows the data structure of graph information. It is explanatory drawing (the 2) which shows the data structure of graph information. It is explanatory drawing which shows the specific example of the search result of a 2nd search process. It is explanatory drawing which shows an example of the longest wiring path | route which passes through a part of some cyclic circuit. It is explanatory drawing which shows the example of an output of a search result. It is explanatory drawing which shows the flow of a series of processes at the time of a division | segmentation. It is a flowchart which shows an example of the design support process sequence of a design support apparatus. It is a flowchart which shows an example of the specific process sequence of a 1st search process. It is a flowchart which shows an example of the specific process sequence of a 2nd search process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Design support apparatus 200,600 Wiring area 300 Wiring information 400 Coordinate table 501 Search part 502 Calculation part 503 Determination part 504 Output part 505 Change part 506 Dividing part

Claims (8)

Computer
Search means for searching for a wiring path connecting the first and second terminals arranged in the predetermined wiring area, and a circuit in the predetermined wiring area and not connected to the wiring path;
Calculating means for calculating a wiring path length that combines the wiring path length of the wiring path searched by the searching means and the wiring path length of the circuit;
Determining means for determining whether or not the wiring path length calculated by the calculating means is equal to or longer than a wiring path length satisfying a specified circuit characteristic;
Output means for outputting the determination result determined by the determination means;
Design support program characterized by functioning as The search means includes
When the determination means determines that the length is equal to or longer than the wiring path length, the longest wiring from the first terminal to the second terminal after passing through a part of the wiring path and a part of the circuit Explore the route,
The output means includes
2. The design support program according to claim 1, wherein the longest wiring route searched by the search means is output. The calculating means includes
Calculating the wiring path length of the longest wiring path searched by the search means;
The determination means includes
The design support program according to claim 2, wherein it is determined whether or not a wiring path length of the longest wiring path calculated by the calculating unit is equal to or longer than a wiring path length satisfying the circuit characteristics of the specification. The computer,
Function as a changing means for changing the longest wiring path,
The determination means includes
Determining whether the difference between the wiring path length of the longest wiring path and the wiring path length satisfying the circuit characteristics of the specification is within a preset allowable range;
The changing means is
When it is determined that the determination means is outside the allowable range, the longest wiring path is changed to be the wiring path length within the allowable range,
The output means includes
The design support program according to claim 3, wherein the longest wiring route after the change changed by the changing unit is output. The computer,
Functioning as a dividing means for dividing the predetermined wiring area into a first wiring area that does not include an obstacle and a second wiring area that includes an obstacle;
In the computer,
The process by the search means, the calculation means, and the determination means is executed for each of the first and second wiring areas divided by the division means. The described design support program. The search means includes
As a result of executing the processing by the search means, the calculation means, and the determination means for each of the first and second wiring areas, a part of the first longest wiring path in the first wiring area and the The longest wiring path from the first terminal to the second terminal through a part of the second longest wiring path in the second wiring region is searched for. 5. The design support program according to 5. Search means for searching for a wiring path connecting the first and second terminals arranged in the predetermined wiring area, and a circuit in the predetermined wiring area and not connected to the wiring path;
Calculating means for calculating a wiring path length combining the wiring path length of the wiring path searched by the searching means and the wiring path length of the circuit;
Determining means for determining whether or not the wiring path length calculated by the calculating means is equal to or longer than a wiring path length satisfying a specified circuit characteristic;
Output means for outputting the determination result determined by the determination means;
A design support apparatus comprising: A search step for searching for a wiring path that connects the first and second terminals arranged in a predetermined wiring area, and a circuit that is not connected to the wiring path in the predetermined wiring area;
A calculation step of calculating a wiring route length that combines the wiring route length of the wiring route searched by the searching step and the wiring route length of the circuit;
A determination step of determining whether or not the wiring path length calculated by the calculation step is equal to or longer than a wiring path length satisfying a specified circuit characteristic;
An output step for outputting the determination result determined by the determination step;
The design support method characterized by including.

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