Flip flop testing

Flip-flops and beach toys are normally also made of externally plasticized PVC in low-wage countries and show an analogous behavior. In 25 of the flip-flops tested by Oko-Test, 17 showed excessive DOP or similar phthalates the same was true of 14 out of 18 tested inflatable beach toys. 

One approach to improve the electron-nuclear polarization transfer rate in ONP experiments is to adapt time-tested Hartmann-Hahn-type approaches. Groups at Heidelberg and Leiden separately developed similar approaches (respectively dubbed Hartmann-Hahn ONP (HHONP) and nuclear orientation via electron spin locking (NOVEL) ) whereby a spin-lock mw pulse sequence is applied to the electrons such that their frequency in the rotating frame matches the Larmor frequency of the H nuclei in the lab frame. Thus, the formerly forbidden electron/nuclear flip-flop transitions effectively become thermodynamically allowed , improving the efficiency of the polarization transfer compared to MIONP experiments performed outside this Hartmann-Hahn condition. The polarization transfer typically occurs on the ps time scale, generally faster than both the electronic T and the triplet lifetime. ... 

A switching speed test was also performed by operating the loop as a flip-flop. Preliminary to the test, the input current was diverted entirely to one branch using a crossed-film cryotron. The inductance switch was then operated, and the current switching time was... 

Tests also show that the circuit of Fig. 6 can be operated as a bistable flip-flop. That is, pulsing an inductance switch shifts most of the current to the opposite branch, and the current thus shifted, remains there. This can be explained only if the flux associated with the small remaining current is trapped in the inductance switch hole. Analysis shows that each time the current is flipped, a smaller amount is shifted, until finally no shift is obtained, and the current is split evenly between the two branches. The entire process can be repeated by interrupting the loop current, pulsing both inductance switch controls, and then applying loop current again. 

Several circuits containing standard threshold switches were chosen to test the feasibility of operating amorphous semiconductor devices in a radiation environment (Ovshinsky et al (1968) Shanks et al (1970a)). Among these circuits were a relaxation oscillator, an astable multivibrator, an AND/OR gate with complementary outputs and a J-K flip-flop. All circuits... 

A muxed scan flip-flop, as the name indicates, consists of a mux and a flip-flop. The output of the mux drives the data input of the flip-flop and the select input is controlled by the test mode pin the inputs to the mux are the data input and the test input as shown in the Figure 1.7. Sequential cells are replaced by scan equivalents to achieve the primary requirement of testability, namely, observability and controllability. A scan cell has two modes of operation, the normal mode and the test... 

Separate negative and positive edge flip-flops into separate hierarchical blocks. In other words, avoid having both kinds of flops in the same hierarchical module. This makes the debug process and timing analysis during synthesis much simpler. Moreover, this can help simplify test insertion. 

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. 

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... 

Check if the Synopsys variable atpgLtest asynchronous pins has been set to false. When true (the default value), both stuck-at-0 and stuck-at-1 faults on asynchronous pins are considered for test generation. When set to false, it allows the user to force asynchronous input pins to all flip-flops to inactive states during the parallel measure and capture phases of a scan test. This implies that no tests will be g erated for stuck-at-inactive-value faults on the asynchronous pins and those faults will be reported as untestable. 

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