JPH0284763A - Integrated circuit - Google Patents

Abstract

PURPOSE:To reduce the signal lines and terminals required for inspection simultaneously enabling the circuit blocks arbitrarily selected from a plurality of circuit blocks successively connected to be inspected by a method wherein transfer circuits selecting the input signals or output signals to and from the first circuit blocks by control signals to be transmitted as the input signals to the circuit block in the next stage are provided. CONSTITUTION:The title integrated circuit is composed of a plurality of circuit blocks 1-3 successively connected as well as transfer circuits 10-12 selecting either the input signals to the first circuit blocks or the output signals from the first block to be transferred to the input signals to the second circuit blocks in the next stage. For example, firstly, the circuit block to be inspected is selected from the circuit blocks 1-3. Secondly, the transfer circuits 10-12 are controlled by control signals from transfer circuit control circuit 16 so that the transfer circuits 10-12 may output the output signals from said selected circuit blocks as well as the input signals to not-selected circuit blocks respectively as output signals. Thus, the input signals from an input signal terminal 17 are inputted to said selected circuit block to output the results to an output terminal 18.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an integrated circuit consisting of a plurality of circuit blocks connected in series.

2. Description of the Related Art Conventionally, in testing semiconductor integrated circuits consisting of a plurality of continuously connected circuit blocks, the output signals of the circuit blocks were directly taken out as test signals. required.

The configuration of a conventional semiconductor integrated circuit will be described below.

Figure 2 is a configuration diagram of a conventional semiconductor integrated circuit.
．． 3 is a circuit block, each of which is in a continuously connected relationship. 4 and 5 are signal lines connecting the circuit blocks; 6
7 is an input signal terminal, 7 is an output signal terminal, and 8.9 is a test signal terminal.

In this conventional example, the input signal 6 is used as the overall input signal, the circuit blocks are continuously connected to process the signal, and 7 is used as the output signal, and the output signal terminal 7 and the inspection terminals 8 and 9 The operation of the circuit blocks is tested by observing signals between the circuit blocks at signal terminals.

Problems to be Solved by the Invention However, the above configuration requires dedicated signal lines and terminals for the number of test signals, but since there is a limit to the number of usable terminals in semiconductor integrated circuits, the number of signals that can be observed is limited. There is a limit. Further, even if a selector is provided to reduce the number of terminals as in the other embodiment shown in FIG. 3, the wiring area required for inspection will increase because the signals between the circuit blocks are taken out respectively.

Further, even if it is intended to input an arbitrary input signal between the circuit blocks, signal lines and terminals that can directly input the input signal between the circuit blocks are required, which increases the area.

The present invention solves the above-mentioned conventional problems.It reduces the number of signal lines and terminals required for inspection, and also makes it possible to inspect a plurality of circuit blocks arbitrarily selected from a plurality of continuously connected circuit blocks. It is an object of the present invention to provide an integrated circuit in which it is possible to inspect an arbitrary plurality of circuit blocks by bypassing the entire circuit.

Means for Solving the Problems In order to achieve this object, the integrated circuit of the present invention is a semiconductor integrated circuit composed of a plurality of continuously connected circuit blocks, in which an input signal to the first circuit block, an input signal to the first circuit block, The output signal from the first circuit block and the control signal are input, and the input signal to the first circuit block or the output signal from the first circuit block is selected according to the control signal, and the next stage The switching circuit is configured such that the input signal of the first circuit block becomes the input signal of the second circuit block at the next stage during inspection.

Effect: With this configuration, it is possible to test any selected circuit block from the plurality of continuously connected circuit blocks by giving it any signal or by bypassing it, and it is also possible to inspect the switching circuit and the control signal. Just hold the line,
The area occupied by signal lines and terminals required for inspection can be reduced.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an integrated circuit in one embodiment of the invention. 1.2.3 are circuit blocks that are continuously connected. 4, 5.6 is an input signal line to the circuit block,
7, 8.9 are output signal lines from the circuit, 10, 11.
12 is a switching circuit, 13.14.15 is a control signal line, 16
17 is an input signal terminal, 18 is an output signal terminal, and 19 is a control signal input terminal.

Regarding the integrated circuit of this example configured as described above,
The operation will be explained below.

First, a circuit block to be inspected is selected from the circuit blocks in 1.2.3. Next, 16 switching circuit control circuits are configured so that the switching circuits 10.11 and 12 output the output signal from the selected circuit block and the input signal to the unselected circuit block as output signals, respectively. and 13
．． It is controlled by the control signal from the control signal line 14.15.

Then, the input signals from the 17 input signal terminals are input to the selected circuit block, and the results are output to the 18 output signal terminals.

Effects of the Invention As described above, according to the present invention, it is possible to test only a selected arbitrary circuit block from the plurality of continuously connected circuit blocks using an arbitrary signal, and it is possible to inspect the signal line for inspection and The area occupied by the terminals can also be reduced compared to conventional techniques, making it possible to realize integrated circuits with excellent inspection efficiency.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an integrated circuit composed of a plurality of continuously connected circuit blocks according to an embodiment of the present invention, and FIG.
FIG. 3 is a configuration diagram that takes into consideration the conventional inspection of the integrated circuit. 1.2.3...Circuit block, 10.11゜1
2... Switching circuit, 16... Control circuit for switching circuit, 19... Control signal input terminal.

Claims (1)

[Claims] It is composed of a plurality of continuously connected circuit blocks, and depending on the control signal, the input signal to the first circuit block or the same
1. An integrated circuit comprising a switching circuit which selects an output signal from the circuit block and inputs the signal to a second circuit block at the next stage.