Biomedical Engineering Reference
In-Depth Information
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No. of Electrodes in Each Te st Group
Figure 5.7
Comparison of test completion time for the Euler-path-based functional test method.
each test group on the test frequency, five iterations of the Euler-path-based
functional test are carried out. Electrodes are tested in groups of 1-5, respec-
tively. The test completion times (assuming test-droplet-routing frequency of
10 Hz) are shown in Figure 5.7.
Figure 5.7 shows that a significant reduction in test completion time is
achieved by increasing the number of electrodes in each test group. For
example, by testing the electrodes in groups of five instead of testing one by
one, the test completion time drops sharply from 332.8 s to 98.2 s (i.e., a 71%
reduction). Note that as a trade-off, whenever an error is observed, we
can only determine a group of five candidate defective functional units.
Nevertheless, even such coarse-grained diagnostic information is useful in
practice for dynamic reconfiguration.
Next, we apply the test-aware design method to generate a pin assign-
ment for the chip layout in Figure 3.11. The test-droplet-routing sequences
derived from the Euler-path-based functional test are combined with the
bioassay schedule. The pin-assignment results are generated as shown in
Figure 5.8. We use the pin assignment generated using the test-oblivious
broadcast-addressing method for comparison, which was shown in Chap-
ter 3, Figure 3.35.
As shown in Figure 5.8, the pin assignment resulting from the test-aware
design method uses 26 control pins, that is, only one more control pin than
the test-oblivious pin assignment (Chapter 3, Figure 3.35). The test-aware
design achieves 100% functional testability, while the test-oblivious result
achieves functional testability of only 76%.
5.3.2 Polymerase Chain reaction (PCr)
For the second assay, we use the mixing stages of the PCR. These stages are
used for rapid enzymatic amplification of specific DNA strands. Its assay
