JPS6259349B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a CAD (Computer Aided Design) device, and more particularly to a printed circuit board design device that automatically arranges components on a printed circuit board, designs print patterns, etc.

Conventionally, automatic design equipment that designs printed circuit boards using CAD has been known.
Pattern creation is automatic, reducing the amount of effort and time required for printed circuit board design.

The center of gravity method is known as a method for automatically arranging printed circuit board parts using this automatic design device.

This center-of-gravity method applies virtual tension to the straight-line distance from the start point to the end point for each wire that interconnects components on the board, and calculates the resultant vector of the tension from all other components to a given component. A wiring method in which the total virtual wiring length of the wiring is shortened by finding the position where the value is zero (hereinafter referred to as the "center of gravity") and repeating the process of placing the component at that center of gravity for each component. It is.

The advantages of this wiring method include that it can be applied regardless of the shape and size of the component, and that the total wiring length on the board can be substantially shortened. On the other hand, the shortcoming is that the wiring density on the board is concentrated in a local area such as the center of the board, so the placement density in that local area increases, making it impossible to connect to that part during automatic wiring performed after component placement. There is a high risk of terminal damage.

Therefore, an arrangement method is required to disperse this wiring density. This method involves dividing the components into multiple groups based on their different connection strengths, then dividing the printed circuit board into the same number of areas as the number of groups, assigning each component group to an appropriate area, and then A method is known in which individual parts are placed within the However, with this method, parts placement within a certain area is performed by focusing only on the mutual positional relationship of the parts within that area, so it is not possible to appropriately reflect the mutual positional relationship with parts in other areas. . For this reason, it cannot be said that distribution of placement density and shortening of total wiring length are necessarily performed appropriately.

The present invention has been made to solve the above-mentioned drawbacks, and its purpose is to appropriately reflect the positional relationship between components even between different areas of a printed circuit board, thereby dispersing the placement density and improving overall It is an object of the present invention to provide a printed circuit board design device capable of designing to shorten wiring length.

The feature of the present invention is that the central processing unit arranges each unplaced component on the printed circuit board at the physical center position of the area where the unplaced component should be placed. The center of gravity of all unplaced parts is calculated hypothetically, and the unplaced parts in a certain area whose center of gravity is shifted toward the area adjacent to that area are moved closer to the adjacent area in order of the degree of shift. Place the above-mentioned placed position as the actual placement position of the part, calculate the center of gravity of the remaining unplaced parts again, and place the unplaced parts in other areas using the same procedure as above based on the calculated center of gravity again. The reason is that the system is configured so that all parts are arranged by repeating the process performed in .

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

This embodiment device is used for tablet 1 and keyboard 2.
key input device 3 such as, and CRT image display device 4
, a photoplotter 5, and a tape puncher 6, each of which is connected to a central processing unit 8 via an I/O port 7, and a storage device 9 is connected to this central processing unit 8. be done. This central processing unit 8 divides the printed circuit board into a plurality of blocks (areas) according to component information on the printed circuit board given from the key input device 3, and arranges the components so that the number of wiring connections between each block is minimized. The layout resultant figure is recorded in the storage device 9, further displayed on the CRT image display device 4, and outputted to the photoplotter 5 as a photomask.

Next, an embodiment of a design operation procedure for arranging components on a printed circuit board by the central processing unit 8 of this embodiment apparatus will be described.

First, perform the following operations as initial division.

As shown in FIG. 2, it is assumed that the printed circuit board 20 is placed in the first quadrant on the XY orthogonal coordinates,
This printed circuit board 20 is divided into four blocks 20 ₁ , 20 by vertical and horizontal lines passing through its center 20 a.
Divided into ₂ , 20 ₃ , and 20 ₄ . Components connected to the terminals of the connector 21 and the terminals of the fixed components in each divided block are assigned to each block. Then, among the parts assigned to each block, the parts that have the strongest connection request,
That is, each block sequentially imports the component having the largest number of connections with these component groups into its own block, and all components are equally divided into four blocks.

Next, the inter-block component movement of the components initially divided as described above will be explained.

For the parts that have undergone initial division, a table of the number of connections between blocks and parts as shown in FIG. 3 is created. This connection number table arranges each component in the horizontal direction and the block to which the component belongs in the vertical direction, and at the intersection of the vertical and horizontal directions, all the components in the corresponding block for the corresponding component are placed. Write the number of connections with the product. At this time, block ₂₀₁ and block 20
₃ , or blocks located diagonally opposite each other, such as block ₂₀₂ and block ₂₀₄ , are weighted by multiplying the number of connections by a coefficient.

The number of wires between blocks of components is checked using this connection number table, and a component whose number of wires between blocks will be reduced if it is moved from the block to which it currently belongs to another block is selected and moved to the other block. When moving parts, if the maximum allowable number of parts in the destination block is exceeded, find a part in that block that can reduce the number of connections by moving it to another block, and move that part to another block. Move to. By repeating this process and dividing the parts into blocks, the number of connections between each block can be minimized.

Next, the arrangement of parts within each block after the inter-block parts movement has been completed as described above will be explained.

First, the operation of arranging components within block ₂₀₁ will be explained using FIG. The positions of center coordinates 20b to 20e of each block ₂₀₁ to ₂₀₄ are determined, and the centers of gravity of all components in block ₂₀₁ are determined assuming that the terminal coordinates of unplaced components of each block are located at these positions. Furthermore, the slots _{23a to 23a of the parts to be placed at the boundary with the blocks 202 and 204} adjacent to the block 201
23h will be provided. Next, from among all the parts in the block ₂₀₁ , parts whose center of gravity is biased towards the block ₂₀₄ , that is, parts with a large Y coordinate value of the obtained center of gravity, are placed in the slots 23a to 23e at the boundary with the block ₂₀₄ . Take out only a few. The extracted parts are arranged in order from the block ₂₀₂ side in order of the larger X coordinate value of the center of gravity, that is, the larger the degree of bias towards the block ₂₀₂ . In the same way, parts with large X coordinate values of the center of gravity are placed in block 20.
A number of slots 23f to 23h on the boundary with ₂ are taken out, and these parts are arranged from the block ₂₀₄ side in descending order of the Y coordinate value of the center of gravity.

Next, parts placement within block ₂₀₂ is performed by the same process as described above. However, in this case, block 2
To find the center of gravity of all parts in block ₂ ,
It is assumed that the components whose placement has been completed at ₀₁ are at their actual positions, and the terminal coordinates of the remaining unplaced components are calculated by moving them to the center coordinates 20f of the remaining portion of block ₂₀₁ . As a result, when arranging components in block ₂₀₂ , the state of component arrangement in block ₂₀₁ is reflected.

Thereafter, the same process is repeated for blocks ₂₀₃ and ₂₀₄ , and for parts that have already been placed, the center of gravity of each part is calculated using the placement position as the absolute position, and the specific placement of the parts in each block is calculated. conduct.

After completing the first intra-block component placement for blocks ₂₀₁ to ₂₀₄ as described above, each block 20 to 204 for which no component placement has been done yet
Exactly the same process is repeated for the slots on the outside of the slot ₂₀₄ (in the direction away from the center 20a), and by sequentially performing this process on the slots further outside, the arrangement of all the parts is completed.

In this way, by recalculating the center of gravity of unplaced parts every time the placement position of some parts is determined, it is possible to calculate the mutual positional relationship of individual parts, especially the positional relationship with parts of other blocks, when placing parts. This can be reflected more appropriately.

Although this embodiment describes the component arrangement when a block is divided into four areas, the present invention is not limited to this, and can generally be applied to cases where a printed circuit board is divided into a plurality of areas. be.

In this way, the device of the present invention arranges components on a printed circuit board in accordance with the following steps (a) to (n).
The interconnection rate of automatic wiring performed later is improved by appropriately reflecting the relationship between the placed components.

(a) Divide the components placed on the printed circuit board into multiple groups based on the difference in the number of wiring connections.

(b) Divide the printed circuit board into areas with the number of groups listed above.

(c) Allocate the components of the groups to the regions, and move the components between the regions so that the number of wiring connections between the regions is minimized.

(d) Find the physical center position of each of the above areas, and assume that all unplaced parts in that area are placed at this center position.

(e) Find the center of gravity of all unplaced parts in a certain area.

(F) For each of two or more adjacent areas adjacent to one area above, select the parts whose center of gravity is shifted toward the adjacent area from among all the unplaced parts in (E) above in order of the degree of shift. The number of objects to be placed along the border with the adjacent area is taken out.

(g) Place a component whose center of gravity is biased toward the adjacent area along the boundary with one of the adjacent areas,
In addition, the degree to which the center of gravity of these parts is biased toward another adjacent region is made smaller as the distance from the other adjacent region increases.

(h) The placed parts placed according to (g) above are assumed to have been placed at that position, and the remaining unplaced parts in that area are assumed to be placed at the center position of the unplaced part of that area. Virtualize.

(li) Perform steps (e) through (h) above sequentially for all remaining areas where parts have not been placed yet.

(J) For the remaining unplaced parts of each area, repeat the steps (e) to (li) above to place the remaining unplaced parts, and place all the parts.

As explained above, according to the present invention, it is possible to avoid local concentration of placement density by dividing components into a plurality of placement areas, and when placing parts within each placement area, Since the placement position state of the components is appropriately reflected, the wiring density can be further distributed and the total wiring length can be shortened, and furthermore, the automatic wiring performed after this component placement can be performed efficiently. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a printed circuit board block division method. FIG. 3 is a diagram illustrating a table of the number of connections between blocks and parts. FIG. 4 is a diagram illustrating the arrangement of components within each block of the printed circuit board. 3... Key input device, 4... CRT image display device, 5... Photo plotter, 8... Central processing unit, 9... Storage device, 20... Printed circuit board, 2
0 ₁ to 20 ₄ ...Block.

Claims (1)

[Scope of Claims] 1. A key input device, a CRT image display device, a photoplotter, and a central processing unit that is coupled to and controls the key input device, the CRT image display device, and the photoplotter, respectively. and a storage device connected to the central processing unit, and the central processing unit divides the printed circuit board into a plurality of regions according to component information on the printed circuit board given from the key input device, and stores data in each region. Components are placed so that the number of wiring connections between areas is minimized, and the resulting figure is recorded in the storage device, displayed on the CRT image display device, and output as a photomask to the photoplotter. In the printed circuit board design apparatus configured in The center of gravity of all unplaced parts is calculated by hypothetically placing them in the area. Place it closer to the adjacent area in order of size, calculate the center of gravity of the remaining unplaced parts again using the above placed position as the actual placement position of the part, and then calculate the center of gravity of the remaining unplaced parts based on this calculated center of gravity again. 1. A printed circuit board design apparatus characterized in that the process of arranging parts in the same manner as described above is repeated for the arrangement of all parts.