JP2724052B2 - Programmable logic element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a programmable logic element having a plurality of logic elements and capable of arbitrarily connecting the logic elements. It relates to a logic element.

[0002]

2. Description of the Related Art A conventional programmable logic element is shown in FIG.
As shown in the figure, logic elements 51 arranged in an array,
A wiring group 53 arranged vertically and horizontally between these logic elements, and a crossing portion of the wiring group 53 arranged vertically and horizontally includes a switching element for programmably connecting upper, lower, left and right wirings. Programmable wiring switch 5
5 and an input / output switch 57, 59 provided for each wiring corresponding to the logic element and for connecting the input / output of the logic element to each wiring. In FIG. 5, the wiring group 53 is configured by three wirings.

For example, in order to connect all the wirings from above, below, left and right in a programmable manner, at least 54 programmable wiring switches (hereinafter referred to as "wiring switches") are used in the conventional example shown in FIG. Needs to be provided. That is, as shown in the wiring examples in FIG. 6 and the combinations of the wiring examples in FIG. 7, all the combinations can be connected by 54 switches. In the drawing, ○ indicates the switching element 61. As the switching element 61, for example, an NM is attached to a simplified SRAM cell 63 as shown in FIG.
For example, a switch with memory configured by connecting the gate electrode of the OS transistor 65 is used. All or some of the wirings can be intermittently connected via the switch with memory, so that an arbitrary wiring can be realized in a programmable manner.

In the programmable logic element having such a configuration, when connecting signals between adjacent logic elements, the number of switches in the wiring switch is reduced in order to enable the connection to the three-way wiring after passing through the wiring switch. There is a problem that it increases.

[0005]

SUMMARY OF THE INVENTION The present invention provides a programmable logic element capable of reducing the number of switches in a wiring switch when adjacent logic elements are programmably connected using a wiring group. The purpose is to:

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a programmable logic element having a plurality of logic elements which can be arbitrarily connected between the logic elements. A logic group arranged vertically and horizontally between the logic elements, and a crossing portion thereof is short-circuited, and a wiring group for programmably connecting the logic elements, and a crossing portion of the wiring group. Provided between, the wiring group is divided into cross-shaped wiring elements,
And a switching means for programmably connecting the wiring elements to each other.

[0007]

The present inventors have conducted research on a large number of design examples, and as a result, it has been found that most (60% or more) of wirings between logic elements connect adjacent logic elements.
The present invention has been made on the basis of such a research result, and when connecting adjacent wiring elements, the number of switching elements in the switching means for programmatically connecting the wirings is reduced to the conventional wiring structure. It is improved so that it is smaller on average.

In other words, according to the present invention, the wiring elements between the switching means are divided into cross-shaped wiring elements that are short-circuited at the intersections and are electrically connected continuously. The connection between the divided cross-shaped wiring elements is performed programmably via switching means. This programmable switching allows the wirings in the straight direction to be connected to each other in a programmable manner. Therefore, compared to the conventional case where the wirings in three directions from one direction are connected to each other in a programmable manner, the switching means in the switching means can be used. The number of switch elements can be reduced to about 1/3.

Therefore, the number of MOSFETs used as switch elements can be reduced, the occupied area is reduced, and high integration is achieved.

The switching means used in the present invention comprises:
This is a conventional switching means having a switching element with a memory, and the switching means already described in the section of the prior art at the beginning can be used.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a programmable logic element according to the present invention. In the programmable logic element, for example, three signal lines are arranged vertically and horizontally between the logic elements 11 arranged in a plurality of arrays and the logic elements 11 to form a wiring group 13. In the wiring group 13, corresponding lines in the vertical direction and the horizontal direction are short-circuited at the intersection, and a programmable wiring switch 15 is disposed in the middle of each of the vertical and horizontal intersections. You. On both sides of the wiring switch provided in the vertical wiring, input / output switches 17 and 19 for programmable connection to the input terminal of the logic element 11 or the output terminal of the logic element 11 are provided.

In the figure, four input lines are connected to the input of the logic element 11 from the input / output switch 17 and two input / output switches are connected to the input / output switch 19 from the output of the logic element 11. Output line is connected. Further, as shown in detail in FIG. 2, for example, three signal lines 13 in the vertical direction cross each other, and four input lines 21 having switches that can be connected in a programmable manner are connected to the logic element 11. Each is connected to an input terminal. The output terminal of the logic element 11 is connected to three signal lines 13 in the vertical direction via two output lines 23 in a programmable and switchable manner.

As shown in FIG. 3, the wiring switch 15 disposed in the middle between the intersections of the wiring groups is, as shown in FIG.
Three signal lines 13A to 13C; 13A 'to 13B, which are connected from both sides of the wiring switch 15 and are arranged in the horizontal direction.
13C 'are connected to each other via nine programmable switching elements indicated by a circle so that they can be connected to either of the two signal lines. This switching element may be the above-mentioned switch with memory.

The number of switching elements provided in the wiring switch 15 is 18 compared with the number of switching elements provided in the wiring switch provided at the intersection of the conventional wiring group, which is 18 and therefore, This means that the number of switching is reduced to about 1/3. When, for example, an NMOS transistor is used as a switch element, the number of switching elements used is reduced, so that the occupied area of the element can be reduced.

Further, as shown in FIG. 4, even in a model case in which a specific wiring element A and adjacent wiring elements are sequentially and programmably connected, the number of switches passed is 4.0 on average. The number of switches passing through the wiring switches in the signal path hardly changes, as compared with the case where the number of switches passing through the conventional wiring switches shown in FIG. 9 is 3.9 on average. In addition, an examination of a case where the element becomes large-scale and various logic elements are connected in a programmable manner has confirmed that the number of switch passages is almost the same between the conventional arrangement and the arrangement of the wiring switch according to the present invention.

As described above, according to the present invention, according to the present invention, a wiring group is divided into cross-shaped electrically connected wiring elements, and these wiring elements are programmably connected via wiring switches. By connecting, the number of wirings that the wiring switch connects to in a programmable manner is reduced, so the number of switching elements used in the wiring switch is reduced, wiring is easy, and switch use efficiency is increased,
The area occupied by the switching element is reduced, and the area is reduced.

The present invention is not limited to the examples shown in the embodiments, but various applications can be considered.

[0019]

According to the present invention, the wiring group is divided into cross-shaped electrically connected wiring elements, and these wiring elements are programmably connected via the wiring switches, whereby the wiring group is used for the wiring switches. Reduce the number of switching elements required, make wiring easier, increase switch use efficiency,
The area occupied by the switching element is reduced, and the area is reduced.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration of a programmable logic element according to the present invention.

FIG. 2 is a diagram showing an example of the input / output switch of FIG. 1;

FIG. 3 is a diagram showing an example of the wiring switch of FIG. 1;

FIG. 4 is an explanatory diagram showing an example of examining the number of switches passed when connected to an adjacent logical element in the wiring switch arrangement of the present invention.

FIG. 5 is a conceptual diagram showing a configuration of a conventional programmable logic element.

FIG. 6 is a diagram showing a wiring example of a conventional programmable wiring switch.

FIG. 7 is a diagram showing possible combinations of programmable wiring switches.

FIG. 8 is a diagram showing an example of a switching element with a memory.

FIG. 9 is an explanatory diagram showing an example of examining the number of switches passed when connected to an adjacent logical element in a conventional wiring switch arrangement.

[Explanation of symbols]

 11 logic element, 13 wiring group or wiring, 15 wiring switch, 17 input / output switch, 21 input line, 23 output line

Claims (1)

(57) [Claims] 1. A programmable logic element comprising a plurality of logic elements and arbitrarily connectable between the logic elements, wherein the logic elements arranged in an array and the logic elements are arranged vertically and horizontally. And a wiring group for connecting the logic elements programmably with their intersections being short-circuited, and the wiring group is provided between the intersections of the wiring groups, and the wiring group is divided into cross-shaped wiring elements. And
Switching means for programmably connecting the wiring elements to each other.