JPH08263321A - Logic circuit emulation device - Google Patents

Abstract

PURPOSE: To ensure an operation in a delay time equivalent to that of an actual LSI without carrying out the change, division or assembly, etc., of a circuit. CONSTITUTION: A logic circuit emulation device 10 is provided with a logical simulation part 12 which calculates the logical value of an output signal against the input waveform of a specific LSI and also calculates the propagation delay time of the preceding logical value, an output waveform memory part 14 which stores the logical value and its propagation delay time that are calculated at the part 12, a waveform output part 18 which outputs the logical value stored in the part 14 to a device 16 to be mounted on the LSI in the propagation delay time stored in the part 14, and a waveform sampling part 20 which outputs the input waveform outputted from the device 16 to the part 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for developing an LSI to be mounted on a specific device, checking the operation of the device,
The present invention relates to a logic circuit emulation device that realizes a pseudo LSI required for software development.

[0002]

2. Description of the Related Art Prior to obtaining the actual LSI, for example, at the stage of completing the design and manufacturing, the LSI
In order to enable operation verification, performance evaluation, and development of software used in the device equipped with
A device that realizes the pseudo operation of the LSI is called a "logic circuit emulation device".

The logic circuit emulation device of the first conventional example realizes a desired logic operation by combining a small-scale general-purpose logic IC.

The logic circuit emulation device of the second conventional example is configured by using an LSI, such as an FPGA (field programmable gate array), which allows a user to freely define a logic circuit. Current FPG
In A, the scale of each logic circuit is relatively small.
Therefore, generally, a plurality of FPGAs are prepared, the logic circuit is divided into a plurality of pieces, and each is mounted on each FPGA.

[0005]

However, in the first conventional example, since there is no versatility for the LSI to be realized,
There was a problem that the circuit had to be modified every time there was a change in the circuit, which required a modification man-hour and a modification period. Moreover,
There is also a problem in that it is necessary to modify the circuit of the logic circuit of the LSI to be realized according to the logic specifications of the general-purpose logic IC.

In the second conventional example, since it is necessary to realize an LSI logic circuit by a plurality of FPGAs, it is necessary to perform placement and wiring / writing work for each FPGA, resulting in a problem of enormous man-hours. is there.

Further, in common with the first and second conventional examples, an LSI to be realized when an asynchronous circuit is realized therein.
There was a problem that different operation occurred. For example,
Due to the difference between the signal propagation delay time in the LSI to be realized and the signal propagation delay time in the FPGA or the general-purpose logic IC, a whisker-like instantaneous logical value displacement (spike) may occur on an unexpected signal. is there.

[0008]

A logic circuit emulation apparatus according to the present invention calculates a logic value of an output signal for an input waveform in a specific LSI and its propagation delay time, and a logic simulation section. An output waveform memory unit for storing the logical value of the output signal and its propagation delay time, and the logical value stored in the output waveform memory unit for the propagation delay time stored in the output waveform memory unit. A waveform output section for outputting to the mounted device and a waveform sampling section for outputting the input waveform output from the mounted apparatus to the logic simulation section are provided.

[0009]

In the logic simulation section, the logic value of the output signal with respect to the input waveform in the specific LSI and its propagation delay time are calculated. The calculated logical value of the output signal and its propagation delay time are temporarily stored in the output waveform memory section. The waveform output unit outputs the logical value stored in the output waveform memory unit to the LSI mounted device at the propagation delay time stored in the output waveform memory unit. Then, there is some response from the mounted device, and the waveform sampling unit outputs this as an input waveform to the logic simulation unit.

[0010]

1 is a functional block diagram showing an embodiment of a logic circuit emulation device according to the present invention.

The logic circuit emulation device 10 includes a logic simulation section 12 for calculating a logic value of an output signal with respect to an input waveform in a specific LSI and its propagation delay time, and a logic value of the output signal calculated by the logic simulation section 12. An output waveform memory unit 14 that stores the propagation delay time, and a waveform that outputs the logical value stored in the output waveform memory unit 14 to the mounted device 16 of the LSI at the propagation delay time stored in the output waveform memory unit 14. The output unit 18 and the waveform sampling unit 20 that outputs the input waveform output from the mounted device 16 to the logic simulation unit 12 are provided.

The logic simulation unit 12 is a computer having a logic simulation function, and is an LSI.
Of the output signal with respect to the input signal and the propagation delay time using the netlist 121 storing the circuit connection information of the above, the simulation library 122 storing the logic specification / propagation delay information, and the information and the built-in computer program. Logic simulator 123 for calculating
It consists of and.

The output waveform memory unit 14, the waveform output unit 18, and the waveform sampling unit 20 constitute a main body 22 of the logic circuit emulation device 10. Body 2
2 is the mounted device 16 through the connectors 241 and 242.
Of the input terminal 261 and the output terminal 262. The connector 241 is connected to the waveform output unit 18 side, and the connector 242 is connected to the waveform sampling unit 20 side. The waveform output unit 18 reads the logical waveform information (logical value) and the output timing information (propagation delay time) stored in the output waveform memory unit 14, and the connector 24 according to the contents.
1 has the function of outputting a logic signal to the mounted device 16. The waveform sampling unit 20 has a function of sampling a logical value of an electric signal obtained from the mounted device 16 through the connector 242 and providing the logic simulator 123 with the information.

FIG. 2 is a table showing an example of data stored in the output waveform memory section 18.

The time stores the absolute time from the start of emulation. The signal name indicates which signal of the plurality of signals connected by the connector 241 is the waveform data. The logical value indicates the logical value given to the signal having the signal name shown therein at the time shown therein. According to the contents described in the output waveform memory unit 14, the waveform output unit 18 outputs the designated logical values to the designated signal at a designated time in order from the top at once.

Next, the logic circuit emulation device 10
The operation of will be described.

First, preparations to be made before starting the operation will be described. First, a signal waveform for initializing all the states of the mounted device 16 is defined in the output waveform memory unit 14. Second, the logic simulation unit 12 stores the netlist 121 of the LSI to be emulated so that the logic value and the propagation delay time of the output signal with respect to the input waveform can be calculated.

Next, the actual operation contents will be described.

(1) As described above, the output pattern memory section 14 stores the initialization pattern and the delay time of the mounted device 16 in advance.

(2) The waveform output unit 18 reads out the logical value and the output time stored in the output waveform memory unit 14 from the beginning, and the mounted device 1 has a corresponding logical value and output timing.
Give all to 6.

(3) At the end of outputting the pattern,
The waveform sampling section 20 monitors changes in the signal. When there is a signal change, the logical value and the elapsed time from the completion of the pattern output this time are fetched.

(4) The fetched information is passed to the logic simulator 123, and the logic simulation is performed by using the information as a change in the input waveform, and the corresponding change in the output signal and
The propagation delay time from the change of the input waveform to the change of the output signal is calculated.

(5) As a result of calculation, the time when the change occurs
The signal name / logical value is additionally stored in the output waveform memory unit 14.

By repeating steps (2) to (5) thereafter, it is possible to gradually lengthen the time during which the emulation is being executed.

In the logic simulation section 12, a plurality of simulation libraries 122 are stored, for example, those having the minimum delay time and the maximum delay time. Then select one when running emulation,
By applying it to the logic simulation, it is emulated as an LSI that operates with a desired delay time.

After proceeding with the emulation,
The function of saving the input waveform data given to the logic simulator 123 and the data stored in the output waveform memory unit 14 and the data stored in the logic simulator 1
23 and a function of calling to the output waveform memory unit 14. As a result, when re-emulating, it is not necessary to re-execute from the beginning, and emulation can be restarted from the middle.

[0027]

According to the logic circuit emulation device of the present invention, the logical value of the output signal with respect to the input waveform in the LSI and its propagation delay time are calculated, and the logical value is used as the propagation delay time to be mounted on the LSI. Since the data is output to the device, it is possible to obtain an operation with a delay time equivalent to that of an actual LSI. Therefore, it is possible to completely eliminate the work such as circuit change, circuit division, or circuit assembly, which has been conventionally required to use the FPGA or the general-purpose logic IC.

Also, by using a library referred to in the logic simulator with a maximum delay time or a minimum delay time, emulation can be performed under conditions that are difficult for an actual LSI.

Further, by making the data stored in the output waveform memory section usable in the emulations thereafter and thereafter, the logic circuit emulation can be efficiently performed.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an embodiment of a logic circuit emulation device according to the present invention.

FIG. 2 is a table showing an example of data stored in an output waveform memory unit in the logic circuit emulation device of FIG.

[Explanation of symbols]

 10 logic circuit emulation device 12 logic simulation unit 14 output waveform memory unit 16 LSI mounted device 18 waveform output unit 20 waveform sampling unit

Claims (3)

[Claims] 1. A logic simulation unit for calculating a logical value of an output signal and its propagation delay time with respect to an input waveform in a specific LSI, and a logical value of the output signal calculated by this logic simulation unit and its propagation delay time are stored. An output waveform memory section, a waveform output section for outputting the logical value stored in the output waveform memory section to the LSI mounted device with the propagation delay time stored in the output waveform memory section, and the mounted device A logic circuit emulation device including a waveform sampling unit that outputs the input waveform output from the logic simulation unit to the logic simulation unit. 2. The logic simulation unit has a plurality of delay time libraries, any of which can be selected.
The logic circuit emulation device according to claim 1. 3. The logic circuit emulation device according to claim 1, wherein the data stored in the output waveform memory section can be used in emulation from the next time onward.