Digital waveform analyzer

• US 4,873,647 A
• Filed: 01/11/1988
• Issued: 10/10/1989
• Est. Priority Date: 01/11/1988
• Status: Expired due to Term

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: Minc Incorporated
• Inventors: Banki, Mehrdad, Bush, Kevin M., McDermith, William O.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): TESKA, KEVIN J
• Application Number:
  US07/142,652
• Time in Patent Office: 638 Days
• Field of Search: 364/200, 364/300, 364/900, 364/578, 364/487-491, 340/347 DD, 341/50, 341/78, 341/126, 341/144, 341/155, 324/77 R
• US Class Current: 716/102
• CPC Class Codes: G06F 30/30 Circuit design

Abstract

An automated waveform analyzer for designing, on a computer, a logic implementation of an interface circuit connected between a first digital device and one or more other digital devices. The analyzer identifies from the remaining input and output waveforms those waveforms that, when logically combined together, construct the waveform of a selected output waveform in order to provide the proper logic and timing compatibility between the devices.

Claims

1. An automated waveform analysis method for designing, on a computer, a logic implementation of an interface circuit connected between at least one first digital device and at least one second digital device from inputted data to said computer, said inputted data being an input and output waveforms from said first and second digital devices to said interface circuit so that said interface device permits logic and timing compatibility between said first and second devices, said computer having an input, a memory, and an output, said method comprising the steps of:

(a) inputting into said input of said computer the following waveform information;

(1) identity of each of said input and output waveforms, (2) whether each said waveform is an input or an output, (3) a time for each asserted and non-asserted pulse in each of said waveforms,

(b) storing in said memory of said computer said waveform information;

(c) selecting, via said computer from said memory an output waveform;

(d) identifying, via said computer, in said memory those waveforms or their compliments which alone or logically combined with other waveforms stored in said memory constructs a waveform corresponding to said selected output waveform so that said constructed waveform permits said logical and timing capability,

(e) storing in said memory of said computer design information necessary for said construction of said selected output, said design information including;

(1) identity of each of said waveforms necessary to construct said selected output for said compatibility, (2) a logical operation required such as compliment, AND, or OR for each aforesaid identified waveform, and (3) a time for each asserted and non-asserted pulse in said constructed waveform,

(f) repeating steps (c) through (e) for each remaining output waveform in said memory, and

(g) delivering to said output of said computer said design information signals when all output waveforms have been selected.

2. The method of claim 1 wherein the step of inputting further comprises the step of entering said waveform information into a symbol table in said memory in the form of:

space="preserve" listing-type="equation">XX 0/I V.sub.1 ;

t.sub.1 V.sub.2 ;

t.sub.2 V.sub.1 ;

t.sub.3 V.sub.2;

t.sub.4

where

XX=identity of said waveform;

O/I=whether the waveform is an output or an input;

V1=non-asserted state of the waveform;

V2=asserted state of the waveform; and

t=time unit of assertion or non-assertion.

3. The method of claim 1 in which the step of identifying further comprises the step of determining, via said computer, all waveforms in said memory which are periodic with the asserted pulses of said selected output, periodic waveforms being those waveforms that have the same pattern each time said selected output is asserted.

4. The method of claim 1 in which the step of identifying further comprises the step of finding, via said computer, all waveforms in said memory that have a previous edge one time unit prior to a first edge of said selected output.

5. The method of claim 1 in which the step of identifying further comprises the step of fining, via said computer, a best waveform of all waveforms wherein said best waveform is the waveform having an asserted pulse with the most overlap with the asserted pulse of said selected output.

6. The method of claim 1 in which the step of identifying further comprises the step of checking the uniqueness of each waveform, said step of checking uniqueness comprising each of the following steps:

(a) passing a condition of Unique Previous wherein the waveform has a unique edge one time unit previous to a first edge of said selected signal without a transition prior to said unique edge while said selected output is in the non-asserted state,

(b) passing a condition of Unique End wherein the waveform must end before said selected output ends, and

(c) passing a condition of Unique After wherein the waveform must remain in an unasserted state up to one time unit before said selected output again becomes asserted.

7. An automated waveform analysis method for designing, on a computer, a logic implementation of an interface circuit connected between at least one first digital device and at least one second digital device from inputted data to said computer, said inputted data being an input and output waveforms from said first and second digital devices to said interface circuit so that said interface device permits logic and timing compatibility between said first and second devices, said computer having an input, a memory, and an output, said method comprising the steps of:

(a) inputting into said input of said computer the following waveform information;

(1) identity of each of said input and output waveforms, (2) whether each said waveform is an input or an output, (3) a time for each asserted and non-asserted pulse in each of said waveforms,

(b) storing in said memory of said computer said waveform information,

(c) selecting, via said computer, from said memory an output waveform,

(d) identifying, via said computer, in said memory those waveforms or their compliments which alone or either ANDed or ORed with other waveforms stored in said memory constructs a waveform corresponding to said selected output waveform so that said constructed waveform permits said logical and timing compatibility,

(e) storing in said memory of said computer design information necessary for said construction of said selected output, said design information including;

(1) identity of each of said waveforms necessary to construct said selected output for said compatibility, (2) a logical operation required such as compliment, AND, or OR for each aforesaid identified waveform, and (3) a time for each asserted and non-asserted pulse in said constructed waveform,

(f) storing in said memory of said computer an error signal in the event said step of identifying is unable to construct a waveform corresponding to said selected output.

(g) repeating steps (c) through (f) for each remaining output waveform in said memory, and

(h) delivering to said output of said computer said design information and error signals when all output waveforms have been selected.

8. The method of claim 7 wherein the step of inputting further comprises the step of entering said waveform information into an Available List in a symbol table in said memory in the form of:

space="preserve" listing-type="equation">XX O/I V.sub.1 ;

t.sub.1 V.sub.2 ;

t.sub.2 V.sub.1 ;

t.sub.3 V.sub.2 ;

t.sub.4

where

XX=identity of said waveform;

O/I=whether the waveform is an output or an input;

V1=non-asserted state of the waveform;

V2=asserted state of the waveform; and

t=time unit of assertion or non-assertion.

9. The method of claim 7 in which the step of identifying further comprises the step of determining, via said computer, all waveforms in said memory which are periodic with the asserted pulses of said selected output, periodic waveforms being those waveforms that have the same pattern each time said selected output is asserted.

10. The method of claim 7 in which the step of identifying further comprises the step of finding, via said computer, all waveforms in said memory that have a previous edge as time unit prior to a first edge of said selected output.

11. The method of claim 7 in which the step of identifying further comprises the step of finding, via said computer, a best waveform of all waveforms wherein said best waveform is the waveform having an asserted pulse with the most overlap with the asserted pulse of the selected output.

12. The method of claim 7 in which the step of identifying further comprises the step of checking the uniqueness of each waveform, said step of checking uniqueness comprising each of the following steps:

(a) passing a condition of Unique Previous wherein said waveform has a unique edge one time unit previous to a first edge of said selected signal without a transition prior to said unique edge while said selected output is in the non-asserted state,

(b) passing a condition of Unique End wherein said waveform must end before said selected output ends, and

(c) passing a condition of Unique After wherein said waveform must remain in an unasserted state up to one time unit before said selected output becomes asserted.

13. An automated waveform analysis method for designing, on a computer, a logic implementation of an interface circuit connected between at least one first digital device and at least one second digital device from inputted data to said computer, said inputted data being an input and output waveforms from said first and second digital devices to said interface circuit so that said interface device permits logic and timing compatibility between said first and second devices, said computer having an input, a memory, and an output, said method comprising the steps of:

(a) inputting into said input of said computer the following waveform information;

(1) identity of each of said input and output waveforms, (2) whether each said waveform is an input or an output, (3) a time for each asserted and non-asserted pulse in each of said waveforms,

(b) storing in said memory of said computer said waveform information,

(c) selecting, via said computer, from said memory an output waveform,

(d) determining, via said computer, all waveforms in said memory which are periodic with the asserted pulses of said selected output, periodic waveforms being those waveforms that have the same pattern each time said selected output is asserted,

(e) finding, via said computer, all determined periodic waveforms in said memory that have a previous edge one time unit prior to a first edge of said selected output,

(f) finding, via said computer, a best waveform of all found previous edge waveforms wherein said best waveform is the waveform having an asserted pulse with the most overlap with the asserted pulse of said selected output,

(g) checking the uniqueness of each of said determined periodic waveform, said step of checking uniqueness comprising each of the following sub-steps;

(1) passing a condition of Unique Previous wherein said determined periodic waveform has a unique edge one time unit previous to the first edge of said selected signal without a transition prior to said unique edge while said selected output is in the non-asserted state,

(2) passing a condition of Unique End wherein said determined periodic waveform must end before said selected output ends,

(3) passing a condition of Unique After wherein said determined periodic waveform must remain in an unasserted state up to one time unit before said selected output again becomes asserted,

(h) identifying, via said computer, in said memory those waveforms or their compliments which alone or logically combined with other waveforms stored in said memory constructs a waveform passing steps (d) through (g) above corresponding to said selected output waveform so that said constructed waveform permits said logical and timing compatibility,

(i) storing in said memory of said computer design information necessary for said construction of said selected output, said design information including;

(1) identity of each of said waveforms necessary to construct said selected output for said compatibility, (2) a logical operation required such as compliment, AND, or OR for each aforesaid identified waveform, and (3) a time for each asserted and non-asserted pulse in said constructed waveform,

(j) repeating steps through (c) through (i) for each remaining output waveform in said memory, and

(k) delivering to said output of said computer said design information signals when all output waveforms have been selected.

14. The method of claim 13 wherein the step of inputting further comprises the step of entering said waveform information into a symbol table in said memory in the form of:

space="preserve" listing-type="equation">XX O/I V.sub.1 ;

t.sub.1 V.sub.2 ;

t.sub.2 V.sub.1 ;

t.sub.3 V.sub.2 ;

t.sub.4

where

XX=identity of said waveform;

0/I=whether the waveform is an output or an input;

V1=non-asserted state of the waveform;

V2=asserted state of the waveform; and

t=time unit of assertion or non-assertion.

15. An automated waveform analysis system for designing a logic implementation of an interface circuit connected between at least one first digital device and at least one second digital device so that said interface device permits logic and timing compatibility between said first and second devices, said system comprising:

a computer,

means for inputting into said computer the following waveform information;

(1) identity of each of said input and output waveforms, (2) whether each said waveform is an input or an output, and (3) a time for each asserted and non-asserted pulse in each of said waveforms for each input and output waveform from said first and second digital devices to said interface circuit,

means operative with said inputting means for storing in said computer said waveform information,

means operative with said storing means for selecting each output waveform,

means in said computer for identifying those waveforms or their compliments which alone or logically combined with other waveforms in said storing means constructs a waveform corresponding to each said selected output waveform so that said constructed waveform permits said logical and timing compatibility,

means operative with said identifying means for storing the design information necessary for said construction of each said selected output, said design information including;

(1) identity of each of said waveforms necessary to construct said selected output for said compatibility, (2) a logical operation required such as compliment, AND, or OR for each aforesaid identified waveform, and (3) a time for each asserted and non-asserted pulse in said constructed waveform, and

means operative with said design information storing means for delivering said design information signals from said computer when all output waveforms have been selected.