JPS6250860B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a logic simulator that simulates circuit operations etc. by computer processing, and particularly relates to a method for outputting a time chart of a simulation process for logic simulation.

(2) Prior Art and Problems In general, logic simulators output the input/output signals of each gate circuit in the process of simulating circuit operations etc. as time charts to reduce the work of making errors or changes in logic circuits, and to This contributes to making design and development easier.

Conventionally, this type of time chart output method involves sequentially outputting time charts for all hours.

A method of storing the entire time chart in a storage device and then outputting the necessary parts.

A method in which a simulation is performed to check the time at which the trigger signal is generated, then another simulation is performed, and the output of the time chart is started from a time before the same time to obtain the necessary portion.

However, it has the disadvantages that it contains a lot of unnecessary data, requires a large storage capacity, and requires repeating the simulation twice.

(3) Object of the Invention The object of the present invention is to provide a time chart output method that efficiently outputs time charts for the necessary times before and after the time when a desired trigger signal is generated, when outputting time charts in a logic simulator. Our goal is to provide the following.

(4) Structure of the Invention In order to achieve the above object, the present invention stores time chart information in a logic simulator in a storage device with a certain capacity, and stores information that exceeds the capacity of the storage device starting from the oldest one. the time chart information before a certain time from the current time is retained; when a trigger signal is generated, the detection device detects the trigger signal; the control device temporarily stops the operation of the logic simulator upon detection of the trigger signal; Sends the time chart information stored in the storage device to the output device, operates the logic simulator again when the output is completed, stores the time chart information in the storage device, and directly outputs the time chart information for a certain time to the device. This feature is characterized in that only the time charts for a certain period of time before and after the detection time of the trigger signal are output.

(5) Examples of the invention The present invention will be explained in detail below using examples.

FIG. 1 is a block diagram of the time chart output method of the present invention. In the figure, 1 is a logic simulator, 2 is a data distribution device, 3 is a storage device, 4 is a trigger detection device, and 5 is a control device. In a computer processing system, in order to satisfy these functions, the control device CPU and memory are used. It is possible to configure it using MEM. 6 is an output control device, 7 is a display device, and 8 is a printer. Under this configuration, the logic simulator 1 is connected to the data distribution device 2, and data is distributed to the storage device 3, trigger detection device 4, and output device 6. The output device 6 is also connected to the storage device 3. The trigger detection device 4 is connected to a control device 5, and the control device 5 controls the logic simulator 1, the data distribution device 2, and the storage device 3. Normally, the time charts that are output from the logic simulator 1 are sequentially stored in the storage device 3 by the data distribution device 2, and the storage device 3 deletes time charts that exceed a certain capacity from the oldest time charts, and always stores the latest time charts. Memorizes the time chart of the hour and minute. When a desired trigger signal is detected by the trigger detection device 4, the control device 5 temporarily stops the operation of the logic simulator 1 and outputs the time chart stored in the storage device 3 to the output device 6. When the output is completed, the control device 5 operates the logic simulator 1 again, stores the time chart in the storage device 3 through the data distribution device 2, and also sends the time chart for a certain time directly from the data distribution device 2 to the output device 6. Controls output.

According to the present invention, there is an effect of efficiently outputting time charts for a fixed time before and after the trigger signal detection time.

FIG. 2 shows, as an example, a logic circuit configuration to be subjected to logic simulation, and FIG. 3 shows its time chart output result.

The example in Figure 2 shows a shift register circuit, and the input signal terminal is a serial information input terminal.
SERIAL INPUT, data input terminal P-IN-A,
P-IN-B, P-IN-C, P-IN-D, clock signal terminal CLOCK, SERIAL INPUT input and P
-IN- Equipped with a selection terminal SEL to select A, B, C, and D inputs, and consists of an inverter I, an AND circuit A, a NOR circuit NO, a flip-flop circuit FF, etc., and output SERIAL OUT is obtained.

A simulation of a circuit with such a configuration is performed, and for example, when the signal of the output QD of the flip-flop FF changes from logic level "0" to "1" as a trigger, the past elapsed time a and the subsequent fixed time b are calculated.
Each input signal and each FF output QA, QB,
Figure 3 shows the QC and QD time charts printed out from the equipment shown in Figure 1.

In FIG. 3, when a trigger is detected (0→1), the control device 5 temporarily stops the logic simulator and sequentially outputs the past data in the storage device (a
period), when the latest data has been sent to the output device, the logic simulator is restarted, the progress is recorded in the storage device, and it is sent to the output control device to output the period b, and then the control device The simulation continues by stopping or outputting only to the storage device under the instruction of . Note that the output during period a is determined by the storage capacity of the storage device used for cycling.

In this example, the trigger is detected by detecting a change from "0" to "1", but it is of course possible to use detection of the opposite level as the trigger. Further, if it is desired to extract more detailed information on the time chart output, for example, the output signal portion of the AND circuit, this can be done by also sending the progress information of the logic simulator to the storage device and storing it.

Note that the output period of the time chart and the type of output signal in this embodiment etc. depend on the storage capacity of the storage device, and are not intended to limit the configuration of the present invention.

(6) Effects of the Invention According to the present invention, when outputting a time chart in a logic simulator, the time chart is stored in a storage device that always stores only the latest fixed time, and when a trigger signal is detected, the simulator operates. Since it also controls the output operation of the time chart in the storage device, it is possible to efficiently output the time chart at the time before and after the trigger signal generation, and the storage capacity is smaller than the conventional method, and the time chart required for one simulation can be output efficiently. It is possible to obtain output.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention, FIG. 2 is an example of a logic simulation target circuit, and FIG. 3 is a diagram showing an example of a time chart output. In the figure, 1 is a logic simulator, 2 is a data distribution device, 3 is a storage device, 4 is a trigger detection device, 5 is a control device, and 6 is an output device.

Claims (1)

[Claims] 1 The time chart information in the logic simulator is stored in a storage device with a certain capacity, and when the amount exceeds the storage capacity, it is deleted starting from the oldest, and the time chart information from the current time to a certain time is retained. , when a trigger signal is generated, the detection device detects the trigger signal, the control device temporarily stops the operation of the logic simulator upon detection of the trigger signal, and sends time chart information stored in the storage device to the output device; When the output is completed, the logic simulator is operated again, the time chart information is stored in the storage device, and the time chart information for a certain time is directly sent to the output device, so that the time chart information for a certain time before and after the detection time of the trigger signal is A time chart output method characterized by outputting only time charts.