Scan Insertion

Scan cells have two different modes of operation normal and scan. In normal mode, the scan celFs functionality is same as that of the sequential non-scan cell. In scan mode, the scan cells are linked in the form of a shift register. 

Scan insertion results in design overheads such as, the use of extra scan ports, an increase in silicon area due to use of scan flops, and greater timing delays due to the insertion of the scan cells for the sequential non-scan cells. It is possible to reduce the port overheads by sharing the scan ports with functional ports. 

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Figure 7.16 Modulus and damping for a carbon-fibre composite measured by the frequency multiplexing method during a single thermal scan. Insert shows the Arrhenius activation-energy plot from the loss peak position.

Scan technique is the most widely used Design For Testability(DFT) technique, and more importantly, is supported by most test synthesis tools. Iliis technique involves replacing the sequential non-scan cells by scan cells of the desired scan style. This transformation enables the sequential scan cells to be connected as a shift register in the scan mode. Further, for ATPG each of these scan cells behave as a pseudo primaiy input as well as a pseudo primaiy output. In this section, we discuss four basic issues related to Test Synthesis using TC, namely. Scan methodology. Scan Style, Scan Insertion and ASIC Vendor issues. 

This command infers a default test protocol and performs a DRC check by simulating the test protocol. One must execute the check test command before scan insertion as well as after scan insertion. check test is the main debugging command in TC and it s output must be thoroughly analyzed for its implications on the fault coverage. 

Another simpler alternative is to use the Test Smart Compile approach. In this approach the user must specify the scan style before compile. The Test Smart Compile is turned on by specifying the scan style (using set scan style command) before compile. Then, DC automatically ensures that only those sequential cells which have scannable equivalents in the specified scan style, are inferred during optimization. However, for partial scan designs, users may choose to use non-scan cells functionally in critical paths, and choose not to replace diem during scan insertion. 

Analyze the testability of the design prior to scan insertion using the check.test command. A default test protocol is inferred and simulated on executing the check test command. The default test protocol consists of the following initialization vectors, scan-in/scan-out, parallel measure, capture and scan out strobe. 

Perform Scan Insertion using the insert.scan command, insert scan... 

The next phase involves testability analysis after scan insertion. Analyze the testability of your desi using the check test command. 

Eveiy test pattern consists of the following phases scan-shift, parallel measure, parallel capture, and scan-out strobe. You can add initialization vectors at the start of the test program using the read init protocol command. Shown below is the default protocol inferred by TC for a design after scan-insertion. 

During functional mode timing analysis, there might be multi-cycle paths between the flip-flops. In the test-mode, all the flip-flops are clocked in the same cycle. Hence, perform timing analysis on the complete design after scan-insertion, without any path exceptions. Also, use the set clock skew command to account for all the delays on the different clock branches. If the clock tree is in place, use the set clock skew -propagated command. 

You have a design with scan inserted. The scan style used is multiplexed flip-flop and methodology, full scan. Running check test on the post scan design gives a clean report... 

A generator is used for all reporting. Since set up and result information is stored in a Resource File by name, the report generator can scan this file and insert the values wherever the name appears in the user s template... 

Figure 26. Constant current mode STM image of isolated (A), self-organized in close-packed hexagonal network (C) and in fee structure (E) of silver nanoclusters deposited on Au(l 11) substrate (scan size (A) 17.1 x 17.1 nm, f/t=—IV, /t=ltiA, (C) 136 X 136 nm, f/t = — 2.5 V, /t = 0.8 tiA, (E) 143 x 143 nm, = —2.2 V, /, = 0.72 nA). I U) curves and their derivatives in the inserts of isolated (B), self-organized in close-packed hexagonal network (D) and in fee structure (F) of silver nanoclusters deposited on Au(l 11) substrate. (Reprinted with permission from Ref. [58], 2000, Wiley-VCH.)...

Figure 6.10 Galvanostatic scans of a Pt(l 10) rotating disk electrode in a CO-satuiated 0.1 M HCIO4 solution at two different current scan rates (disk rotation rate 400rev/min). The insert shows the potential fluctuations observed at an apphed current density of 0.74 mA/cm (disk rotation rate 900 rev/min).

Figure 14.9 CO bulk electro-oxidation at bare Ru(OOOl) in flow cell dotted line, CO fi ee electrolyte solid lines flow of CO saturated electrolyte, with varied upper scan limits (see key on flgure). (See color insert.)...

Figure 16.8 Pt/TiO c-catalyzed oxygen reduction potential, where 0.01 mA cm is reached during the negative scan in a cyclic voltammetry experiment (scan rate 20 mV s ) in oxygen-saturated 0.5 M HCIO4 at 25 °C. (See color insert.)...

FIG. 5 Potential difference between two Ag/AgCl electrodes in the stem of a soybean plant after insertion of the electrodes. Distance between electrodes was 8 cm. Volume of soil was 0.5 L. The plants were given water every other day and kept at 24°C. Frequency of scanning was 1000 samples per second. 

Wide use of TLC-MS is hampered by the lack of commercially available interfaces. This also restricts automation and high throughput. Commercial direct insertion probes for scanning TLC-MS are available [811]. Compared with on-line LC-MS operation, TLC-MS hyphenation is much less highly developed. 

FIG. 3. Chromosome arms begin to separate in pro metaphase. Scanning electron micrographs of human chromosomes isolated from cells in prophase (A), prometaphase (B), metaphase (C) and early anaphase (insert in C). Size bar, 1 /tm. Reprinted with permission from Sumner (1991). 

Fig. 2.10. Potential step SNLFTIRS spectra from a polished polycrystalline Pt electrode, immersed in 10 2 M CHjOH/O.l M HC104 electrolyte. All spectra (90 scans each, 8 cm 1 resolution) were normalized to the base spectrum collected at 0 mV vs. RHE. Insert part of the curve at 450 mV in expanded scale.

The SEEPR technique allows the simultaneous recording of the CV and the CW EPR spectrum of the radicals produced during the electron transfer reactions (Khaled et al. 1991). The SEEPR technique consists of an IBM enhanced electrolytic cell inserted in a rotating cylindrical EPR cavity. The cell is no longer sold by IBM, but a description can be found (Khaled et al. 1990, 1991). The CVs were obtained using a commercial (BAS-100) electrochemical analyzer while simultaneously recording the EPR spectra during the scan. 

Hallet, B., Sherratt, D.J. and Hayes, F. (1997) Pentapeptide scanning mutagenesis random insertion of a variable five amino acid cassette in a target protein. Nucleic Acids Research, 25, 1866-1867. 

Why do we believe that a Cu monolayer is inserted between SAM and gold substrate The 2D-deposit grows and dissolves extremely slowly. Another indication is that the 2D deposit is very stable and shows no displacement by the scanning tip. Cu clusters on top of an alkanethiol-SAM would be only weakly bound and should be easily pushed away by the tip at higher tunnel currents, very much like metal clusters on a hydrogen-terminated Si(lll) surface, which for that very reason are difficult to image by STM (or AFM [122]). And finally, the cyclic voltammograms (Fig. 33) point to the formation of a buried monolayer . 

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