JPH05266137A - Arrangement design assisting device - Google Patents

Abstract

PURPOSE:To easily design component arrangement in consideration of wiring length by connecting signal lines whose wiring length is limited in the form of a color-classified display of logical connection information. CONSTITUTION:At a request to assist the arrangement of an unarranged component, components which are already arranged are displayed on the screen of a CRT 4 according to position information on the components, and the arranged component in connection relation with the unarranged component is found according to the logical connection information 1 and highlighted and displayed on the screen of the CRT 4. Then, the outward shape of the unarranged component and a land where the component is mounted are moved and displayed on the CRT 4 in synchronism with the motion of a mouse 5. Further, the shortest straight line connecting the land of the unarranged component and the land of the hightlighted arranged component on the screen of the CRT 4 is found, and a color which is predetermined according to the level of the wiring length is added by referring to wiring length limitation specification information 2 to display the straight line. The arrangement coordinates of the unarranged component whose arrangement position is determined is outputted from an external file input/output part 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the design of PWBs and ceramic substrates, and more particularly to a device for supporting the layout design of components.

[0002]

2. Description of the Related Art Recent electronic devices, especially electronic circuits such as computers, have been remarkably improved in performance. Not only is the data processing unit increased to 8 bits, 16 bits, and 32 bits to improve its performance, but the frequency of the electric signal is set to 16 MHZ, 25 MHZ, 3 in order to increase the processing amount per time.
It has been increased to 3 MHZ, and has come to exceed 50 MNZ in the past few years. When the frequency of the electric signal rises in the electronic circuit, the propagation time of the electric signal transmitted through the wiring on the printed circuit board, which was relatively small with respect to the delay time of the element, becomes non-negligible. It's getting tougher. For example, for the wiring of a certain signal line, it is desired that the line length be less than or equal to several centimeters, or that a plurality of signal lines be wired with the same line length. The largest factor that determines the wiring length is the component placement position, and it is required to place components in consideration of the wiring length in advance.

In the conventional layout design support device, the connection relationship between the parts is displayed as a straight line connecting the part pins called rat's nest, and the layout worker can see this display on the screen without seeing the logic circuit diagram. I was arranging the parts by grasping the connection status of the parts.

[0004]

In the conventional layout design support apparatus for PWB and ceramic board design, when arranging components,
The connection relationship is simply displayed as a straight line connecting the component pins obtained by the logical connection information called rat's nest, so it is possible to visually grasp the component layout that satisfies the wiring length required by the system designer as described above. It has the drawback of being difficult.

[0005]

According to the present invention, in a layout design support apparatus for supporting component layout work in PWB or ceramic board design, a mouse, a CRT, and logical connection information between components and position information of already placed components are previously stored. Wiring length limitation designation information for limiting the wiring length between the parts is provided, and in response to a placement support request for unplaced parts, the already placed parts are displayed and designated on the CRT based on the position information of the already placed parts. First means for highlighting the already-arranged component obtained on the basis of the logical connection information for the already-arranged component having a connection relationship with the unarranged component, and the specified unspecified component. Second means for moving and displaying on the CRT screen the outline of the placed parts and the land or pad on which the unplaced parts are mounted according to the movement of the mouse, and the CRT screen The shortest straight line connecting the land or pad of the unplaced component and the land or pad of the highlighted already-placed component is obtained, and is determined in advance according to the level of the wiring length by referring to the wiring length restriction designation information. A third means for displaying the straight line on the CRT screen by adding the specified color, and a fourth means for outputting the arrangement coordinate information of the unarranged component whose arrangement position has been determined to an external file provided in advance. It is characterized by having.

[0006]

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

FIG. 1 is a block diagram showing an embodiment of the present invention. The device according to the present invention includes an external file input / output unit 6
A layout design support processing unit 7, a CRT 4 for displaying layout components and a board layout region, a mouse 5 for moving components to determine layout coordinates, a layout information data map storage area 9, and a logical connection information storage area 10. Then, the logical connection information file 1, the wiring length limitation designation information file 2, and the component information library 3 including the positions and dimensions of the external shape of the component and the lands and pads on which the pins of the component are mounted are input, and the component placement information file 8 is input. Is output.

Next, FIGS. 2 and 3 show flowcharts of the layout design support processing unit in the present invention.

First, in step 1, the logical connection information file 1
Is input from the external file input / output unit 6 and stored in the logical connection information storage area 10. In step 2, the parts placement information file 8 is input and the placement coordinates of the already placed parts are read. Part pin information library 3 for already placed parts in step 3
Is input, the positions of lands and pads on which the component pins of the already-arranged components are mounted are calculated, and the arrangement coordinates of the components and the positions of the lands and pads are stored in the arrangement information data map storage area 9. In step 4, the external shape of existing parts, lands and pads are C
Display on RT4. In step 5, the signal line name and the limited length for which the wiring length is designated are input from the wiring length limitation designation information file 2, and the level is divided into the stages which have been determined in advance. For example, if the wiring length is within 10 cm, the level is A; if the wiring length is within 15 cm, the level is B; Then, the wiring length limitation level is stored in the logical connection information storage area 10 for the signal name for which the wiring length is designated. In step 6, it is checked whether all the parts in the logical connection information storage area 10 have already been arranged. If there are unplaced parts,
In step 7, one of the unplaced parts separately displayed on the CRT 4 is selected by the mouse 5. Let α be the selected component. In step 8, the connection destination part of the part α is searched from the logical connection information storage area 10 by tracing the connection signal line of the part α. In step 9, the component connected to the component α is highlighted on the CRT 4. Next step 10
Then, the component outline of the component α and the land or pad on which the component is mounted are displayed on the screen of the CRT 4 in accordance with the movement of the mouse 5 on the CRT 4. This screen display method will be referred to as a "dragging display" hereinafter. Next, in step 11, the land or pad of the part α and the land or pad of the connection destination part of the part α are searched, and the shortest straight line connecting them is CRT4.
Display heading. This straight line display is called ratsnest. When this rat's nest is displayed on the CRT 4, the wiring length limitation level given in step 5 is derived from the logical connection information storage area 10, and the color of the rat's nest of the corresponding signal line is changed according to the level. For example, the level A is "red", the level B is "yellow", the level C is "green", and so on. Next, in step 12, steps 10 to 11 are repeated until the placement position of the part α is determined by the mouse 5. When the arrangement coordinate of the part α is determined in step 12, the arrangement coordinate of the part α and the position of the land or pad are stored in the wiring information data map storage area 9 in step 13. Next, the process returns to step 7, and steps 7 to 1 are performed until there are no unplaced parts and the operator confirms the completion of the placement work in step 14 and both respond with "Yes".
Repeat 3. After confirming the completion of placement work, step 1
In step 5, the component placement coordinate information on the placement information data map is output to the component placement information file 8 from the external file input / output unit.

FIG. 4 shows an example of a screen display output by the device of the present invention.

[0011]

As described above, according to the present invention, the signal line connection having a limited wiring length is displayed in the form of a rat's nest color-coded display during the component placement work. Is easily performed, and there is an effect of preventing the design of the PWB that causes noise and delay problems.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart of a layout design support processing unit according to the present invention.

FIG. 3 is a flowchart of a layout design support processing unit according to the present invention.

FIG. 4 is a diagram showing a screen display example according to the present invention.

[Explanation of symbols]

 1 Logical Connection Information File 2 Wiring Length Restriction Specification Information File 3 Parts Information Library 4 CRT 5 Mouse 6 External File Input / Output Section 7 Layout Design Support Processing Section 8 Parts Layout Information File 9 Layout Information Data Map Storage Area 10 Logical Connection Information Storage Area

Claims (1)

[Claims] 1. A layout design support device for supporting component layout work in PWB or ceramic board design, comprising:
It is provided with a mouse, a CRT, and logical connection information between parts, position information of already-arranged parts, and wiring length restriction designation information for restricting the wiring length between the parts in advance. Based on the position information of the already-arranged parts, the already-arranged parts which are displayed on the CRT and have a connection relationship with the specified unarranged parts are obtained based on the logical connection information. First means for highlighting on the CRT screen, and the outline of the designated unplaced component and the land or pad on which the unplaced component is mounted are moved and displayed on the CRT screen in accordance with the movement of the mouse. The second means and the shortest straight line connecting the land or pad of the unplaced component on the CRT screen and the land or pad of the highlighted already placed component are obtained. Third means for displaying the straight line on the CRT screen by adding a predetermined color according to the level of the wiring length with reference to the length limit designation information, and the placement of the unplaced component whose placement position is determined A layout design support device, comprising: a fourth means for outputting coordinate information to an external file provided in advance.