JPS6217831A - Asynchronous signal generating circuit - Google Patents

Abstract

PURPOSE:To transmit the change of an asynchronous signal to an asynchronous circuit at a rapid timing and to control the asynchronous circuit by using a part of the output of a state change recognizing circuit as an asynchronous signal changing signal. CONSTITUTION:The asynchronous circuit (unshown) is controlled by an asynchronous signal 102, i.e. a state value, which is an output from a decoder circuit 13. On the other hand, a partial circuit in the asynchronous circuit is also controlled by the state change of the asynchronous circuit, i.e. an asynchronous signal changing signal 101. A delay time is prepared during the period from the sending of a state changing signal from the state change recognizing circuit 11 to the output of an asynchronous signal from a decoder circuit 13. However, a part of the asynchronous circuit can be controlled at a rapid timing accelerated by the delay time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an asynchronous signal generating circuit that outputs an asynchronous signal for controlling an asynchronous circuit.

[Conventional technology]

Conventionally, this type of asynchronous signal generation circuit has a state flip-flop circuit that holds the state value of the asynchronous circuit, a decoder circuit that decodes the output of this state flip-flop circuit, and a state change recognition circuit that recognizes the state change of the asynchronous circuit. The decoder circuit output is used as an asynchronous signal to control the asynchronous circuit.

[Problem that the invention seeks to solve]

By the way, in the above-mentioned asynchronous signal generation circuit, the decoder circuit output is simply used as an asynchronous signal to control the asynchronous circuit.

In terms of performance, asynchronous circuits require the asynchronous signal to change at a faster timing, but there is a problem in that the change timing of the asynchronous signal cannot be made earlier, and the performance does not match the performance of the asynchronous circuit.

[Failure to solve the problem]

The present invention provides a state flip-flop circuit that defines the operating state of an asynchronous circuit and holds a state value, a decoder circuit that decodes the output of this state flip-flop circuit and generates an asynchronous signal, and an output of this decoder circuit. It has a state change recognition circuit that recognizes the state change of the asynchronous circuit based on the control information input from the control information pin and transmits it to the state flip-flop circuit. Alternatively, the asynchronous signal generating circuit is characterized in that it is used as an asynchronous signal change signal that conveys a falling edge.

〔Example〕

The present invention will be explained below with reference to Examples.

FIG. 1 is a block diagram of an asynchronous signal generation circuit according to the present invention.

Referring to FIG. 1, a state fritsoff circuit 12 that holds the current state value of an asynchronous circuit (not shown) is connected to a decoder circuit 13, and from this circuit 13 a digital signal is transmitted. O3102 is output, and this asynchronous signal 102 is input to the asynchronous circuit. On the other hand, the output of the decoder circuit 1, ie, the asynchronous signal 102, is inputted to the state change recognition circuit 11. Further, a control information input pin 14 for inputting control information is connected to this state change recognition circuit 11. The state change recognition circuit 11 is connected to a state flip-flop circuit 12, and a part of the output of the state change recognition circuit 11 is input to the asynchronous circuit as an asynchronous signal change signal to be described later.

The current state value of the asynchronous circuit held by the state flip-flop circuit 12 is input to the decoder circuit 3, and this state value is decoded here.

It is output as an asynchronous signal 102. This asynchronous signal 1
02 is input to the asynchronous circuit to control the asynchronous circuit. On the other hand, as described above, the asynchronous signal 102 is inputted to the state change recognition circuit 11. The state change recognition circuit 11 uses only the asynchronous signal 102.

Alternatively, a change in the state of the asynchronous circuit is recognized by the asynchronous signal 102 and control information (control signal) input from the control information input pin 14, and this recognized change in state (state change signal) is applied to the flip-flop of the IJ. The state is transmitted to a flip-flop circuit 12 consisting of a flip-flop circuit.

A state change signal from the state change recognition circuit 11 sets or resets the state flip-flop in the state flip-flop circuit 12 to hold the next state value, and this new state value is transferred to the decoder circuit. 13 and output as an asynchronous signal.

Incidentally, the asynchronous circuit is controlled by the asynchronous signal 102 that is the output of the decoder circuit 13, that is, by the state value, but some circuits within the asynchronous circuit can also be controlled by the state change of the asynchronous circuit, that is, the asynchronous signal change signal. It is.

Referring also to FIG. 2, there is a delay time shown in FIG. 2 from when the state change recognition circuit 11 sends out the state change signal until the decoder circuit 13 outputs the asynchronous signal. That is, a state change signal is sent at timing 1,
An asynchronous signal is sent out at timing 3 (timing 2 is the output timing of the state flip-flop circuit 12). Therefore, as mentioned above, if the asynchronous circuit requires the asynchronous signal to change at a faster timing in terms of performance, the output of the asynchronous signal will be delayed by the delay time indicated by -.

It is not compatible with the performance aspects of asynchronous circuits.

In the above embodiment, instead of being part of the asynchronous signal.

That is, the state change signal from the state change recognition circuit 1 is inputted to the asynchronous circuit as an asynchronous signal change signal 101 together with the asynchronous signal. In other words, the asynchronous circuit has timing 1.
The output of the state change recognition circuit 11 (asynchronous signal change signal)
is input, it is possible to control a part of the asynchronous circuit at a faster timing by the delay time.

As described above, when the asynchronous signal has a large influence on the performance of the asynchronous circuit and a control signal is required at a faster timing, it is effective to use an asynchronous signal change signal.

[Effects of the Invention] As explained above, in the asynchronous signal generation circuit according to the present invention, since a part of the output of the state change recognition circuit is used as the asynchronous signal change signal, the asynchronous signal changes at a faster timing. can be transmitted to the asynchronous circuit, and as a result, the asynchronous circuit can be controlled with quick timing, which has the effect of improving the performance of the asynchronous circuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an asynchronous signal generating circuit according to the present invention, and FIG. 2 is a time chart of the asynchronous signal generating circuit shown in FIG. DESCRIPTION OF SYMBOLS 11... State change recognition circuit, 12... State flip-flop circuit, 13... Decoder circuit, 14... Control information input pin, 101... Asynchronous signal change signal. 102...Asynchronous signal. Agent (7783) Patent attorney Noriyasu Ikeda

Claims (1)

[Claims] 1. In an asynchronous signal generation circuit that outputs an asynchronous signal for controlling an asynchronous circuit, a state flip-flop circuit that defines the operating state of the asynchronous circuit and holds a state value, and a state flip-flop circuit that decodes the output of the state flip-flop circuit. A decoder circuit that generates an asynchronous signal, and a state change recognition circuit that recognizes a state change of the asynchronous circuit based on the output of the decoder circuit and control information input from a control information pin and transmits it to the state flip-flop circuit. have,
An asynchronous signal generation circuit characterized in that a part of the output of the state change recognition circuit is used as an asynchronous signal change signal that conveys the rise or fall of the asynchronous signal.