Fast Answers & Questions about the Tw-CAD

Questions & UUT e-mail to:zvp@unitel.spb.ru ==> to Victor Zviaguine

1. What circuits can the Tw-CAD manupulate with?
2. Are there other CADs to design tests?
3. What is "TestWard" term?
4. What are minimal requirements for the circuits to be processed ?
5. Is it possible to generate test for arbitrary circuit with the Tw-CAD automatically
6. How can the customer justify additional cost ?
7. Are you planning to develop the Tw-CAD ?
8. When did you start working on the Tw-CAD project ?
9. Is the Tw-CAD compatible with other CADs ?
10. What advantages has the Tw-CAD over competitors in the class of the similar CADs ?
11. What are the Tw-CAD requirements to IBM-PC ?
12. Is it possible to unite the Tw-CAD with other CADs ?
13. What kind of testers may be used by designer ?
14. What happens with the Tw-CAD as the area of application of
the JTAG standard expends ?
15. Is it great overhead needed by the Tw-CAD modifications recommended ?
16. Is demo-version of the Tw-CAD exist?
17. Is the Tw-CAD portable ?
18. What features do confirm serious image of the Tw-CAD ?
19. Are there distinctions in the test design technology provided by the Tw-CAD and traditional CADs ?
20. What is the role of Designer in the test design technology provided by the Tw-CAD?
21. What are relationships of Designer and the Tw-CAD?
22. How does the Tw-CAD concern to testable architecture of JTAG?
23. Does application area of the Tw-CAD become narrow when the JTAG-style of design been used?
24. What kinds of tests can one generate with the Tw-CAD?
25. Are there facilities of project verification in the Tw-CAD ?

1. What circuits can the Tw-CAD manupulate with?
- Tw-CAD may deal with any digital circuits with gates, ICs, LSIs,
PLDs, gate arrays, slice microprocessors. Number of gates is
restricted to 10 000 (in DOS environment),
restricted to 100 000 (for WINDOWS-95/98 environment). on top

2. Are there other CADs to design tests ?
- Yes, there are. The Tw-CAD technology differs (see FAQ#19 too) from traditional one. Usually designer creates tests and testable modifications
manually. Following to the suggested technology user can generate
complete Test ware with the Tw-CAD automatically. on top

3. What is "TestWard" term ?
- TestWard is a new term abbrevated "Tw" and offered in the title of the system. Testward is all-round care about fault grade prognosis for source circuit and that of the circuit with testable modifications recommended by the Tw-CAD. Tw is ATPG and test adaptations for the testable circuit. Tw is software and hardware for testing. on top

4. What are minimal requirements for the circuits to be processed ?
- Initialization sequences are to exist. ROMs, RAMs, CPUs and pulse generators are to be isolated by means of mechanics or electronics.on top

5. Is it possible to generate test of arbitrary circuit with Tw-CAD
automatically ?
Not absolutely so, situation of arbitrary circuit becomes more certain:
- test is provided for the testable circuit,
- testable modifications are provided to transform untestable circuit to the testable one.
on top

6.How can the customer justify additional cost ?
1) you may order TestWare instead design it
2) if you get license you can use the low cost IBM-PC platform, may be the same computer you have;
3) designer may not worry about TestWare (the Tw-CAD makes this hard task). So designer can concentrate on circuit projects;
4) low cost tester may be used;
5) high quality of TestWare will be our common success. on top

7. Are you planning to develop the Tw-CAD ?
- Yes, of cause. There are 4 directions :
1) growth of circuit dimension enabled (100 000 gates under WINDOWS);
2) JTAG-style of the testable modifications will be provided;
3) the Tw-CAD and the Tw-tester will be integrated together to support JTAG style of designs;
4) the Tw-CAD will penetrate into CAD/CAE environment as workstation for TestWare.on top

8. When did you start working on a Tw-CAD project ?
- The Tw-CAD is based on original publications since 1977.
We began working on like system 360/370 oriented project in 1976, on DOS IBM-PC oriented project in 1988, on WINDOWS 3.1 oriented project in 1993 and on WINDOWS-95/98/NT oriented project in 1997. on top

9. Is the Tw-CAD compatible with other CADs ?
- The Tw-CAD is compatible :
at the input with: MAX Plus II, PCAD, RedBoard, OSE, (OrCAD, DixiCAD), so on..;
at the output with: MAX Plus II, PCAD, DixiCAD, LASAR, MR-CAD (OrCAD) and so on...
It is the MAX Plus II of Altera is today main system to cooperate. on top

10. What advantages does Tw-CAD have over competitors in the class of the similar CADs ? Compare please with other CADs..
- Traditional IBM-PC oriented CADs are supplied with simulation and verification, seldom with fault grade routines. They are not supplied with ATPG and DFT analysis usually. These features are seldom or are absent in the more serious CADs too. The Tw-CAD has all above features. As we know facility of automatic generation of testable modifications is unique too. Timing and delay information are not needed to handle with your circuit in the Tw-CAD. The Tw-CAD is oriented to automated design thereby batch mode is main approach to system organization. We do not concetrate on creation of schematic and waveform editors. on top

11.What are the Tw-CAD requirements to IBM-PC ?
- Usual configuration is available:
IBM-PC/AT 1mb for DOS 5.0 ,
IBM-PC/386 4mb for WINDOWS 3.1,
IBM-PC/Pentium 64mb for WINDOWS-95/98                on top

12. Is it possible to unite the Tw-CAD with other CADs ?
- Yes, it is. The NET_LIST at the output of any network editor is the only needed data to generate test automatically wiith the Tw-CAD. It is certainly advisable because this editor is already used by designer to draw his circuit usually. The Tw-CAD output is the test generated. Test is destined to other CADs or to any     tester directly                                                              on top

13. What kind of testers may be used by designer ?
- there is flexible programmable interface to connect the Tw-CAD with any user's tester or CAD immediately

- own Tw-tester may be used (the HW & SW of the sample tester were designed. We are interested in investors to organize production of testers);                  on top

14. What happens with the Tw-CAD as the area of application of the JTAG standard expends ?
- Application area of the Tw-CAD extends too due to the test points recommended by the Tw-CAD may be supplied with the JTAG-type ICs, LSIs, PLDs                    on top

15. Is it great overhead needed by the Tw-CAD modifications recommended ?
- No it is not. It is reduced by decimal degree opposite usual LSSD or other known approaches. Designer can realize modifications in JTAG-style based upon scan architecture on top

16. Does demo-version of Tw-CAD exist?
- Yes, It exists. It occupies 2 diskettes. It is restricted by 400 gates. It is supplied with "Primer of the Tw-CAD". This is DOS version.
Copying of the Tw-CAD demo-version is free                     on top

17. Is the Tw-CAD portable ?
- Yes, it is. The Tw-CAD codes (near 80,000 statements written in Fortran & C) have been transferred to IBM-PC from System 360/370-type mainframe. It has been transferred from DOS to WINDOWS 3.1 environment too, from WINDOWS to WINDOWS-95/98/NT environment too without almost changing needed.                                      on top

18. What features do confirm serious image of the Tw-CAD?
- original methods and technology,
- analysis of complex nodes permits to deal with any schematics (tri stable, resistors, buses, relays)
- 300 IC Library and the enabling to add new elements,
- 10 000 / 100 000 gates are dimensional limits of the circuits,
- 2 languages (Russian and English) to communicate with users,
- 200 pages Manual,
- 500 articles on error massages,
- 90 design's routes,
- 80 000 statements of FORTRAN-90 and C programs,
- 6 Mbytes of run-files in DOS format,
- 1,5 Mbytes of HELP-files
- since 1979 thousands of tests have been designed and used, especially for the space verchicle units. on top

19. Are there distinctions in the test design technology provided by the Tw-CAD and traditional CADs? - Distinctions are radical:
First figure offers traditional manual technology

Second and third figures offer for the present automatic double-pass DFT & TFD technology

on top

20. What is the role of Designer in the test design technology provided by the Tw-CAD?
He is the key figure in design process:
- he creates the circuit;
- he sets available level of additional hardware in DFT & he sets the threshold of reliable fault coverage;
- he creates the library of schematics to realize JTAG architecture                            on top

21.What is the relationship of Designer and the Tw-CAD?
These relationship is partnership: Designer fulfils intellectual work to create project of the circuit exact opposite the Tw-CAD helps him in hard thorough work on creation of TestWare         on top

22.How is the Tw-CAD concern to the testable architcture of the JTAG style?
- The Tw-CAD provides additional controlability and observability points which would be realized in JTAG architecture                                 on top

23. Would you think that application area of the Tw-CAD becoms narrow when the JTAG-style of design been used?
- Opposite having such kind devices it is easy to realize control and observation points recommended by the Tw-CAD                                       on top

24.What kinds of tests can one generate with the Tw-CAD?
- Tw-CAD yelds complete set of tests:
- for verification;
- DC tests to check HW;
- AC tests to check dynamics;
- tests for parametrics                   on top

25.Are there features of project verification in the Tw-CAD?
The Tw-CAD offers wide spectrum of verification tools:
- almost traditional simulation of user's verification test (without any timing information needed);
- ATPG for verification especially ;
- bus consistency analysis;
- cross simulation between project realized & prototype project;
- express verification by prototype without tests. on top