JPH0547130B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a multi-value logic circuit, and particularly to a four-value binary conversion circuit that converts a four-value logic signal into a binary logic signal. [Prior Art] In semiconductor logic integrated circuits, as the degree of integration increases, the area required for wiring increases as a percentage of the entire chip. Conventionally, multilayer wiring technology has been developed and put into practical use as a means of reducing this wiring area. [Problems to be Solved by the Invention] The conventional multilayer wiring technology described above still has the drawback that the number of wiring nets increases. Therefore, a method has been proposed in which the number of wiring lines itself is halved by transmitting signals within the chip using four values. An object of the present invention is to provide a 4-value to binary conversion circuit which is one of the circuits for realizing this intra-chip 4-value signal transmission system, and which converts a 4-value logic signal into a binary logic signal. . [Means for Solving the Problems] The four-value to binary conversion circuit of the present invention divides the power supply voltage range into four voltage ranges and assigns logical values 0, 1, and 2 to the divided voltage ranges from the low voltage side. , 3 is assigned as an input signal, a first determination circuit that determines a logical value 0 and a logical value 1, and a logical value 2 and a logical value 3, and outputs the result as a binary signal. , a logical value subtraction circuit that converts logical value 3 to logical value 2, logical value 2 to logical value 1, and logical value 0.
and a logic value addition circuit that converts the logic value 1 to a logic value 1 and the logic value 1 to a logic value 2, and the four-value input signal is input to the first determination circuit, the logic value subtraction circuit, and the logic value addition circuit. and sets the output result of the first determination circuit as a first output signal, and furthermore, when the determination result of the first determination circuit is (logical value 0 or logical value 1), the output signal of the logical value addition circuit. select the signal obtained by passing it through the second judgment circuit,
When the determination result is (logical value 2 or logical value 3), a signal obtained from the output signal of the logical value subtraction circuit through the second determination circuit is selected as the second output signal. [Example] Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. A four-value input signal is input to an input terminal 10, and the signal becomes an input signal to a determination circuit 11, a logic value addition circuit 12, and a logic value subtraction circuit 13. Judgment circuit 1
1 and 15 output the logical value 0 of binary logic signals 0 and 1 when the 4-value input signal is a logical value 0 or 1, and output the logical value 0 of the binary logic signal 0 and 1 when the 4-value input signal is a logical value 2 or 3. Outputs the value 1. Logical value addition circuit 1
2 outputs a 4-value logical value 1 when the 4-value input signal is a logical value 0, and outputs a 4-value logical value 1 when the 4-value input signal is a logical value 1.
Outputs the value logical value 2. The logic value subtraction circuit 13 is 4
When the value input signal is a logical value 3 and a logical value 2, a four-value logical value 2 and a four-value logical value 1 are output, respectively. The selection circuit 14 outputs a signal from the logical value addition circuit 12 when the output of the determination circuit 11 is a binary logical value 0, and outputs the signal from the logical value subtraction circuit 13 when the output of the determination circuit 11 is a binary logical value 1. This is a switch that outputs a signal. Next, the principle of operation will be explained in detail. (1) When the four-value input signal has a logical value of 0, the determination circuit 11 outputs a binary logical value of 0. The logic value addition circuit 12 outputs a four-value logic value 1. Therefore, the output of the selection circuit 14 becomes a four-value logic value 1, and the output of the determination circuit 15 becomes a two-value logic value 0. In other words,
Both binary output signals A and B appearing at output terminals 16 and 17 have a logic value of 0. (2) When the four-value input signal has a logical value of 1, the determination circuit 11 outputs a binary logical value of 0. The logic value addition circuit 12 outputs a four-value logic value 2. Therefore, the output of the selection circuit 14 becomes a four-value logical value 2, and the determination circuit 15 outputs a binary logical value 1. In other words,
The binary output signals A and B have a logic value of 1 and a logic value of 0, respectively. (3) When the four-value input signal has a logical value of 2, the determination circuit 11 outputs a binary logical value of 1. The logic value subtraction circuit 13 outputs a four-value logic value 1. Therefore, the output of the selection circuit 14 becomes a four-value logic value 1, and since the determination circuit 15 outputs a binary logic value 0, the binary output signals A and B become a logic value 0 and a logic value 1, respectively. (4) When the four-value input signal has a logical value of 3, the determination circuit 11 outputs a binary logical value of 1. The logic value subtraction circuit 13 outputs a four-value logic value 2. Therefore, the output of the selection circuit 14 is a four-value logical value 2, and the output of the determination circuit 15 is a binary logical value 1, so the binary output signals A and B both have a logical value 1. From (1) to (4) above, the truth table shown in Table 1 is obtained,
A four-value input signal is converted to a two-value output.

〔Effect of the invention〕

As explained above, the present invention can relatively easily provide a circuit that converts a four-valued logic signal into a two-valued logic signal, and can be applied within an integrated circuit to perform intra-chip signal transmission using the four-valued logic signal. By doing so, the number of wiring lines within the chip is reduced and the wiring area occupied by the entire chip is significantly reduced, which has the effect of reducing the chip area.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
Figure 2 shows the 4-value to binary conversion circuit in Figure 1.
FIG. 2 is a circuit diagram showing an example realized using a CMOS circuit. 10, 20...4-value signal input terminal, 11, 1
5, 21, 25... Judgment circuit, 12, 22... Logical value addition circuit, 13, 23... Logical value subtraction circuit,
14, 24...Selection circuit, 16, 17, 26, 2
7...Binary signal output terminal.

Claims (1)

[Claims] 1 Divide the power supply voltage range into four voltage ranges and set each divided voltage range with logic values 0, 0, and 0 from the low voltage side.
In a logic circuit whose input signal is a four-value logic signal that assigns 1, 2, and 3, a first logic circuit that determines logic value 0 and logic value 1, logic value 2 and logic value 3, and outputs it as a binary signal. A determination circuit, a logical value subtraction circuit that converts logical value 3 to logical value 2, logical value 2 to logical value 1, logical value 0 to logical value 1, and logical value 1 to logical value 2. a logical value addition circuit, the four-value input signal is input to the first determination circuit, the logical value subtraction circuit, and the logical value addition circuit, and the output result of the first determination circuit is input to the first output. selecting a signal obtained by passing the output signal of the logical value addition circuit through a second determination circuit when the determination result of the first determination circuit is (logical value 0 or logical value 1); When the determination result is (logical value 2 or logical value 3), the output signal of the logical value subtraction circuit is passed through the second determination circuit, and the obtained signal is selected and used as the second output signal. A four-value to two-value conversion circuit.