JP2957333B2 - Unused input line detection method in space switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting unused input lines in a space switch.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional unused input line detection system in a space switch includes N input selector circuits 31 to 3M that input data to input terminals 11 to 1N, and N input selector circuits 31 to 3M. Control circuits 41 to 4M for supplying control signals to
Decoder circuits 51 to 5M for decoding 4M output;
M input OR circuit 61 for taking a logical OR of outputs (O1 to ON) of decoder circuits 51 to 5M for each same terminal number
To 6N, an N-bit latch circuit 85 receiving the outputs of the M-input OR circuits 61 to 6N as data inputs, and a latch circuit 85
Control circuit 83 for providing a control signal to the input terminal, and an N-input selector circuit 82 for receiving the output of the latch circuit 85 as a data input.
And a control circuit 84 for providing a control signal to the N-input selector circuit 82, and an output terminal 73 for outputting an output signal of the N-input selector circuit 82.

Next, the operation of this configuration will be described.

The initial value 0 is written in the latch circuit 85 by the initialization control circuit 83. N input selector circuit 3
Reference numeral 1 denotes an arbitrary input terminal selected by the switching control circuit 41. As for the output of the decoder circuit 51, only one output terminal corresponding to the selected input terminal position outputs a logical value of 1 and the other output terminals output a logical value of 0. Similarly, the outputs O1 to ON of the decoder circuits 52 to 5M output the logical value 1 at the output terminal positions corresponding to the input terminals selected by the N input selector circuits 32 to 3M, respectively. The outputs of the M-input OR circuits 61 to 6N, which take the logical OR of the same terminal numbers of the outputs O1 to ON of the decoder circuits 51 to 5M, are latched by an N-bit latch circuit 85.

The bit position of the latch circuit 85 at which the logical value becomes 0 becomes an unused input line, and its information is output to an output terminal 73 through an N input selector circuit 82.

[0006]

In the conventional system for detecting unused input lines in a space switch, the number of input lines of the space switch is reduced by the scale per decoder circuit and the M input O.
Since the number of R circuits is proportional, and the scale per M input OR circuit and the number of decoder circuits are proportional to the number of output lines,
There is a problem that the circuit size increases as the switch size of the space switch increases.

An object of the present invention is to provide a method for detecting an unused input line in a space switch having a small circuit size even if the switch size becomes large.

[0008]

According to the present invention, there are provided M N-input selector circuits for selecting data from N input terminals and outputting data to M output terminals, respectively. M switching control circuits for providing a control signal to each of the N input selector circuits, an M input selector circuit for receiving data from the outputs of the M switching control circuits, and a control for providing a control signal to the M input selector circuit Circuit and
Unused input line detecting means for detecting an unused input line by using an output of the M input selector circuit as a data input.

Further, according to the present invention, the unused input line detecting means includes: a first two-input selector circuit that receives the output of the M-input selector circuit and the output of the counter circuit as data inputs; A second two-input selector circuit that inputs a fixed value of logical value 0 as a data input, an initialization control circuit that supplies a control signal to the first and second two-input selector circuits,
It is preferable to include a RAM that uses the output of the second two-input selector circuit as a data input and uses the output of the first two-input selector circuit as a write address, and a read control circuit that provides a read address to the RAM.

Further, according to the present invention, the unused input line detecting means includes a decoder circuit having an input of the output of the M input selector circuit as an input, and a set input having an output of the decoder circuit as an input. It is preferable to include an N-bit RSFF whose output is a reset input, an N-input selector circuit whose data input is the output of the RSFF, and a control circuit that supplies a control signal to the N-input selector circuit.

[0011]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing one embodiment of the present invention, and FIG. 2 is a circuit diagram showing one embodiment of the unused input line detecting means shown in FIG.

As shown in FIG. 1, the unused input line detection method in the space switch is composed of input terminals 11-1N and 11-1N.
N-input selector circuit 3 using N input terminals as data input
Switching control circuits 41 to 4M for providing control signals to N input selector circuits 31 to 3M, output terminals 21 to 2M to which data outputs of N input selector circuits 31 to 3M are connected, and switching control circuit 41 An M-input selector circuit 71 which receives data of up to 4M as a data input, and a control circuit 72 which supplies a control signal to the M-input selector circuit 71
And an unused input line detecting means for receiving the data output of the M input selector circuit 71 as an input, and an output terminal 73 for outputting an output signal of the unused input line detecting means.

Further, as shown in FIG. 2, the unused input line detecting means is connected to the output of the counter circuit 77 and the M in FIG.
A two-input selector circuit 74 that uses the output of the input selector circuit 71 as a data input, a two-input selector circuit 75 that uses a fixed value of a logical value 1 and a logical value 0 as a data input, and control signals to the two-input selector circuits 74 and 75 An initialization control circuit 78 that supplies the output of the two-input selector circuit 75 as a data input, a RAM 76 that uses the output of the two-input selector circuit 74 as a write address, a read control circuit 79 that supplies a read address to the RAM 76, An output terminal 73 for outputting a data output.

Next, a method of detecting an unused input line when the unused input line detecting means of FIG. 2 is used will be described.

First, the input on the logical value 0 side of the two-input selector circuit 75 is selected by the initialization control circuit 78, and the two-input selector circuit 74 selects the output of the counter circuit 77.
The logical value 0 is written to all the words of the AM 76 and the RAM 76 is written.
Is initialized. After initialization, the two-input selector circuit 7
5 selects an input on the logical value 1 side, and a 2-input selector circuit 7
4 selects the output of the M input selector 71 in FIG. Next, the M input selector circuit 71 uses the control circuit 72 to sequentially select the outputs of the switching control circuits 41 to 4M. The output values of the selected switching control circuits 41 to 4M become the addresses where the logical value 1 is written in the RAM 76. Therefore, after the M-input selector circuit 71 has selected all of the switching control circuits 41 to 4M, the address where the logical value 1 has not been written, that is,
An address having a logical value of 0 corresponds to an unused input line. RA
The data of M76 is output to the output terminal 73 by the read control circuit 79.

FIG. 3 is a circuit diagram showing another embodiment of the unused input line detecting means shown in FIG.

In FIG. 3, the unused input line detecting means includes a decoder circuit 80 to which the output of the M-input selector circuit 71 is input, an output O1 to ON of the decoder circuit to be set inputs, and an output of the initialization control circuit 83. , A N-bit RSFF 81 having a reset input as an input, an N-input selector circuit 82 having an output of the RSFF 81 as a data input, a control circuit 84 for supplying a control signal to the N-input selector circuit 82,
An output terminal 73 for outputting the output of the input selector circuit 82 is provided.

Next, a method of detecting an unused input line when the unused input line detecting means of FIG. 3 is used will be described.

First, RSF is performed by the initialization control circuit 83.
All the N bits of the output of F81 are reset to the logical value 0, and then the M input selector circuit 71 selects the outputs of the switching control circuits 41 to 4M in order. The decoder circuit 80 decodes the output of the switching control circuit,
Only one output terminal corresponding to the selected input terminal position outputs a logical value of 1 and the other output terminals output a logical value of 0. The outputs O1 to ON of the decoder circuit 80 are N bits R
Since the set input of the SFF 81 is made, after the M-input selector circuit 71 finishes selecting all the switching control circuits 41 to 4M, the bit position where the logical value of the N-bit RSFF 81 is 0 corresponds to an unused input line. The data of the RSFF 81 is output to the output terminal 73 by the N-input selector circuit 82 and the control circuit 84.

[0021]

As described above, according to the present invention, each control signal of a group of selectors for switching input lines in a space switch is used as an address input for a storage circuit having a word length of the number of input lines of the space switch. The data is written to the storage circuit, the address is switched by one address decoder by using a selector, and the address to which the data is not finally written is used for the determination of the unused input line. Even if the size increases, there is an effect that an unused input line in the space switch can be detected with a small circuit configuration.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 is a circuit diagram showing one embodiment of an unused input line detecting means in the present invention.

FIG. 3 is a circuit diagram showing another embodiment of the unused input line detecting means in the present invention.

FIG. 4 is a circuit diagram showing a conventional example.

[Explanation of symbols]

 11 to 1N input terminals 21 to 2M, 73 output terminals 31 to 3M, 82 N input selector circuits 41 to 4M switching control circuits 51 to 5M, 80 decoder circuits 61 to 6N M input OR circuits 71 M input selector circuits 72, 84 Control Circuits 74, 75 Two-input selector circuit 76 RAM 77 Counter circuit 78, 83 Initialization control circuit 79 Read control circuit 81 RSFF 85 Latch circuit

Continuation of front page (72) Inventor Akihiro Shiratori 3-20-4 Nishi-Shimbashi, Minato-ku, Tokyo Japan Electric Engineering Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) H04Q 3/52

Claims (3)

(57) [Claims] 1. An M-input selector circuit for selecting data from N input terminals and outputting data to M output terminals, and controlling each of the M N-input selector circuits. M switching control circuits for providing signals, an M input selector circuit for receiving data from the outputs of the M switching control circuits, a control circuit for supplying a control signal to the M input selector circuit, and the M input selector circuit An unused input line detecting means for detecting an unused input line by using the output of the data input as a data input. 2. An unused input line detecting means, comprising: a first two-input selector circuit that receives an output of the M-input selector circuit and an output of a counter circuit as data inputs; and a fixed value of a logical value 1 and a logical value 0. A two-input selector circuit for inputting data as a data input, an initialization control circuit for providing a control signal to the first and second two-input selector circuits, and an output of the second two-input selector circuit as a data input 2. The unused input line detection system in a space switch according to claim 1, further comprising: a RAM having an output of said first two-input selector circuit as a write address; and a read control circuit for giving a read address to said RAM. 3. The unused input line detecting means includes: a decoder circuit receiving an output of the M input selector circuit; a set input receiving an output of the decoder circuit; and a reset input receiving an output of the initialization control circuit. N-bit RSFF
2. The unused input line detection system in a space switch according to claim 1, further comprising: an N-input selector circuit that receives an output of the RSFF as a data input; and a control circuit that supplies a control signal to the N-input selector circuit.