Test scan clock

Figured. Pre-test (left) and post-test (right) scans of the fracture in Berea sandstone. Dark tones are high density, and light are low density. Fracture runs one o clock to seven o clock. Note post-test closure of the fracture in the 5 cm diameter core. [Courtesy AB.. Polak].

For parallel scan-like test without a compactor, an N x N microfluidic array needs N clock cycles to route all test-outcome droplets consecutively to the sink node connected with the... 

For parallel scan-like test with a compactor, 3 X (log2N - 1) clock cycles are needed to compress the test-outcome droplets to one droplet. The detection of the droplet at the compactor output takes 30 s using the photodiode detector [10]. This duration is comparable to the compaction time therefore it must be taken into account when calculating the total time-cost for result evaluation. The comparison of the result-evaluation time for the two methods, assuming a typical clock frequency of 1 Hz, is shown in Fig. 18. 

PCB. A fault isolation test plan must be developed and implemented. The test plan must be able to isolate a fault to a single chip or chip-to-chip interconnection. It is best to base such a plan on the use of chips with boundary scan (Fig. 8.119). With boundary scan chips, test vectors can be scanned in serially into registers around each chip. The MCM can then be run for one clock cycle, and the results scanned out. The results are used to determine which chip or interconnection has failed. If boundary scan is not available, and repair is viewed as necessary, then an alternative means for sensitizing between-chip faults is needed. 

Figure 8.1 shows a multiplexed flip-flop scan cell. In this chapter, we discuss only the multiplexed flip-flop scan style. However, most of the test design rules discussed are also applicable to other scan styles. This scan style is supported by most ASIC vendors. For a multiplexed flip-flop scan style the scan ports required are the scan-iny scan-enabley and scan-out ports. The normal clock is used in the test mode in this scan style. 

TC uses the signaLtype attribute to identify scan ports. Functional ports can be identified as scan ports, by assigning this attribute using the set.signaLtype command. TC creates scan ports automatically if no functional ports are identified with the signaLtype attribute. In the muxed flip-flop scan style, where normal clock is used as test clock, one must not associate a signaLtype attribute, testjclock with the clock port. 

Specify the test methodology, scan style, number of scan chains, mixing of clock domains in the scan chain etc. using the set scan configuration command. 

The default test protocol inferred by TC has four phases Scan Shift, Parallel Measure, Parallel Capture, and Scan-Out Strobe. Each test pattern has all these phases. The length of the scan shift phase is equal to the length of the longest scan chain in the design. The remaining three phases are of one cycle with the test clock being pulsed in only during scan shift and the parallel capture cycle. Shown below are the values of the bi-directionals in the different phases ... 

By default, TC allocates all scan cells clocked by the same clock, to the same scan chain. Also, scan cells clocked by different edges of the clock are placed in different scan chains. Hence, if one has only one test clock in the testmode, because of multiplexing the functional clocks, TC will place all the scan cells in the same scan chain, by default. 

Set the timing attributes for scan testing of the design appropriately, to avoid simulation mismatches. Set test default bldlr delay to a value after the rising edge of the capture clock. This variable specifies the time when data is applied to the bi-directionals in the input mode. 

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 are running DRC (check test) on the top level after integrating your ASIC. Finding that TC is inferring the a nchronous reset line as a clock and all the scan cells with asynchronous reset pins being classified as constant-logic black-box cells. 

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