JPH02185131A - Counter device - Google Patents

Abstract

PURPOSE:To obtain a counter device which sets plural different initial values without using selector circuits and is operated by setting at least one input terminal of a counter circuit to a fixed value and using the output signal of an OR circuit as the load signal. CONSTITUTION:When an input terminal A is used for the least significant bit(LSB), the input terminal A is fixed to '1', and a frame pulse (high level) is applied to an OR circuit 2 and an input terminal C. When the frame pulse is first inputted, the input terminal C of a counter circuit 1 goes to '1', and initial value '0101' is loaded since the input terminal A is fixed to '1', and the counter circuit 1 starts the operation with this initial value. At the time of carry-out of the counter circuit 1, a carry-out pulse is only inputted to the OR circuit 2. Consequently, the counter circuit 1 after carry-out is set to '001' by only '1' inputted to the input terminal A, and the operation is started with this value.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial field of application Prior art (Figure 5) Means for solving the problems to be solved by the invention (Figure 1) Working examples (Figure 2) ~Figure 4) Effects of the Invention [Summary] The present invention relates to a counter device, and provides a counter device that operates by setting a first initial value and a second initial value different from the first initial value without using a selector circuit. In a counter device that operates with a first initial value and a second initial value different from the initial value, the counter circuit includes a plurality of input setting terminals;
A load signal output means for outputting a load signal using a pulse or a carry-out pulse is provided, at least one of the input setting terminals of the counter circuit is set to a fixed value, and a first
The configuration is such that a set value is added to an input setting terminal different from the input setting terminal by the pulse.

(Industrial Application Field) The present invention relates to a counter device, and particularly to a counter device that can operate with a first initial value and a second initial value different from the first initial value.

[Conventional technology]

For example, in a transmission path using a digital line, a frame counter is used to detect the beginning of a frame signal when obtaining data of a frame signal to be transmitted. In a counter device used in such a case, the initial value when a frame pulse is normally input does not match the initial value after carry-out of the counter device for indicating an intra-frame cycle.

Conventionally, in a counter device that operates with a first initial value and a second initial value different from the first initial value, a selector circuit is built into the counter device as shown in FIG. , a method was adopted in which each initial value was applied to the selector circuit to select the initial value to be input and set to the counter circuit.

An example of this is explained in FIG.

A conventional counter device includes a counter circuit 1 having a plurality of input terminals, an OR circuit 2 to which a frame pulse and a carry-out pulse are input, and an initial value a of the frame pulse and an initial value of the carry-out pulse having a value different from this. A selector circuit 4 whose value is applied in advance is connected as shown in the figure.

When a frame pulse is input to this counting device, it is also input to the control terminal a' of the selector circuit 4, which selects and outputs the first initial value a, and the counter circuit 1 sets this first initial value a. be done. When the carry-out pulse is input to the control terminal b' of the selector circuit 4, the second initial value is selected and output, and the counter circuit 1 is set to the second initial value.

[Problem to be solved by the invention]

However, as described above, the conventional counter device always requires the selector circuit 4, and this selector circuit 4 occupies a non-negligible hardware size in the counter device.

Therefore, it is an object of the present invention to
A counter device that performs such operations is provided.

[Means to solve the problem]

In order to achieve the above object, in the present invention, as shown in FIG. 1, at least one of the input terminals of the counter circuit 1, e.g., A, is set to a fixed value, e.g. The output signal of the OR circuit 2 is used as the output signal of the OR circuit 2. The OR circuit 2 receives a frame pulse or a carry-out pulse and operates as an output section that outputs a load signal.

In addition, the frame pulse is input to a specific input terminal of the counter circuit 1.
For example, it is input to C.

[Effect]

When a frame pulse is input, the counter circuit 1 is loaded with a first initial value determined by a specific terminal A to which the fixed value is input and a specific terminal C to which the frame pulse is input, and the counter circuit 1 is loaded with this initial value. Starts operation by.

When the counter circuit 1 carries out, the carry-out pulse is input to the OR circuit 2.

This time, the counter circuit 1 is loaded to the second initial value set only by the fixed value input to the specific terminal A,
The counter circuit 1 operates with this as the initial value.

〔Example〕

Embodiments of the present invention will be described in detail with reference to FIGS. 2 to 4.

(1) First embodiment (Fig. 2) In a counter circuit l with a 4-bit configuration, the initial value of the frame pulse is set to the numerical value "5" as the first initial value, and the initial value after carry-out is set as the second initial value. A case where the value is set to the numerical value rlJ will be explained.

In FIG. 2, the same symbols as in FIG. 1 indicate the same parts.

In this case, if the lowest pitch (LSB) is input terminal A, input terminal A is fixed to "L" and the frame pulse (H
level) is applied to the OR circuit 2 and input terminal C.

First, when a frame pulse is input, the input terminal C of the counter circuit 1 becomes "1" and the input terminal A becomes "1".
Therefore, "0IO1" is loaded as the initial value, and the counter circuit l starts operating with this initial value.

Next, when the counter circuit 1 carries out, the carry-out pulse is only input to the OR circuit 2. Therefore, the counter circuit I after carry-out is set to "0001" only by "1" inputted to the input terminal A, and thereby starts operation.

(2) Second Embodiment (FIG. 3) A case will be described in which, in a 4-bit counter circuit 1, the initial value of the frame pulse is set to the numerical value "3", and the initial value after carry-out is set to the numerical value "2".

In FIG. 3, the same reference numerals as in FIG. 1 indicate the same parts.

In this case, if LSB is input terminal A, input terminal B is
1", and a frame pulse (1 level) is also applied to input terminal A.

First, when a frame pulse is input, the counter circuit 1
The input terminal A of is rl, and the initial value is roll
'' is loaded, and the counter circuit l starts operating with this initial value.

When there is a next carry-out, the carry-out pulse is only input to the OR circuit 2, so the initial value of the counter circuit 1 after the carry-out is determined by rl, which is input to the input terminal B, as "roolo". Set.

As a result, the counter circuit 1 starts operating.

(3) Third Embodiment (FIG. 4) A case will be described in which, in a 4-bit counter circuit 1, the initial value of the frame pulse is set to the numerical value "5" and the initial value after carry-out is set to the numerical value "2".

In FIG. 4, the same reference numerals as in FIG. 1 indicate the same parts, and 3 indicates an inverter.

In this case, input terminals A, C and input terminal B are always inverted. Therefore, the frame pulse (H level) is input to terminal A,
B and C, but it is applied to input terminal B via the inverter 3.

When a frame pulse is input, input terminals A and C of the counter circuit 1 become rlJ, and input terminal B becomes "0", so rololJ is loaded as an initial value. Therefore, the counter circuit 1 starts operating with this initial value.

In the next case of carry-out, the carry-out pulse is only input to the OR circuit 2, so the initial value of the counter circuit 1 is loaded with "0010", and the counter circuit 1 starts operating with this initial value.

In each of the above embodiments, a counter device having a 4-bit counter circuit has been described, but the present invention is not limited to this, and it goes without saying that counter circuits having other numbers of bits can also be applied.

〔Effect of the invention〕

According to the present invention, it is possible to provide a counter device that operates by setting a plurality of different initial values without using a selector circuit, and it is possible to reduce the hardware scale of the counter device, that is, to reduce the size of the device. can.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the principle of the present invention, Fig. 2 is a block diagram of the structure of the first embodiment of the invention, Fig. 3 is a block diagram of the structure of the second embodiment of the invention, and Fig. 4 is a block diagram of the structure of the second embodiment of the invention. FIG. 5 is a block diagram of the configuration of the third embodiment, and FIG. 5 is a block diagram of the configuration of the conventional example. 1--counter circuit, 2--OR circuit, 3-inverter, 4-selector circuit.

Claims (1)

[Claims] A counter device that operates with a first initial value and a second initial value different from the initial value, comprising: a counter circuit (1) having a plurality of input setting terminals; A load signal output means (2) is provided for outputting a load signal by a carry-out pulse, and at least one of the input setting terminals of the counter circuit is set to a fixed value, and an input setting terminal different from the input setting terminal by the first pulse is provided. A counter device characterized in that a set value is added to the counter device.