Flip-Flop

To prevent any possibility of a "race" condition occurring when both the S and R inputs are at logic 1 when the CLK input falls from logic 1 to logic 0, we must somehow prevent one of those inputs from having an effect on the master latch in the circuit. At the same time, we still want the flip-flop to be able to change state on each falling edge of the CLK input, if the input logic signals call for this. Therefore, the S or R input to be disabled depends on the current state of the slave latch outputs.

If the Q output is a logic 1 (the flip-flop is in the "Set" state), the S input can't make it any more set than it already is. Therefore, we can disable the S input without disabling the flip-flop under these conditions. In the same way, if the Q output is logic 0 (the flip-flop is Reset), the R input can be disabled without causing any harm. If we can accomplish this without too much trouble, we will have solved the problem of the "race" condition.

The circuit below shows the solution. To the RS flip-flop we have added two new connections from the Q and Q' outputs back to the original input gates. Remember that a NAND gate may have any number of inputs, so this causes no trouble. To show that we have done this, we change the designations of the logic inputs and of the flip-flop itself. The inputs are now designated J (instead of S) and K (instead of R). The entire circuit is known as a JK flip-flop.

In most ways, the JK flip-flop behaves just like the RS flip-flop. The Q and Q' outputs will only change state on the falling edge of the CLK signal, and the J and K inputs will control the future output state pretty much as before. However, there are some important differences.

Since one of the two logic inputs is always disabled according to the output state of the overall flip-flop, the master latch cannot change state back and forth while the CLK input is at logic 1. Instead, the enabled input can change the state of the master latch once, after which this latch will not change again. This was not true of the RS flip-flop.

If both the J and K inputs are held at logic 1 and the CLK signal continues to change, the Q and Q' outputs will simply change state with each falling edge of the CLK signal. (The master latch circuit will change state with each rising edge of CLK.) We can use this characteristic to advantage in a number of ways. A flip-flop built specifically to operate this way is typically designated as a T (for Toggle) flip-flop. The lone T input is in fact the CLK input for other types of flip-flops.
The JK flip-flop must be edge triggered in this manner. Any level-triggered JK latch circuit will oscillate rapidly if all three inputs are held at logic 1. This is not very useful. For the same reason, the T flip-flop must also be edge triggered. For both types, this is the only way to ensure that the flip-flop will change state only once on any given clock pulse.

Because the behavior of the JK flip-flop is completely predictable under all conditions, this is the preferred type of flip-flop for most logic circuit designs. The RS flip-flop is only used in applications where it can be guaranteed that both R and S cannot be logic 1 at the same time.

At the same time, there are some additional useful configurations of both latches and flip-flops. In the next pages, we will look first at the major configurations and note their properties. Then we will see how multiple flip-flops or latches can be combined to perform useful functions and operations

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INTEGRATED CIRCUIT SYSTEM

ICS9FG107
7-Output PCI-Express, 3 PCI 33MHz Clock Generator from 14.318MHz or 25MHz XTAL
Features

•Generates common CPU/PCI Express frequencies from 14.318 MHz or 25 MHz
•Crystal or reference input
•7 - 0.7V current-mode differential output pairs
•3 - 33MHz PCI outputs
•1 - REFOUT
•Supports Serial-ATA at 100 MHz
•Two spread spectrum modes: 0 to -0.5 downspread and +/-0.25% centerspread
•Unused inputs may be disabled in either driven or Hi-Z state for power management.

Description

ICS9FG107 is a Frequency Timing Generator that provides 7 differential output pairs that are compliant to the Intel CK409/ CK410 specification. It provides support for PCI-Express, next generation I/O, and SATA. The part synthesizes several output frequencies from either a 14.31818 Mhz crystal or a 25 MHz crystal. The device can also be driven by a reference input clock instead of a crystal. It provides outputs with cycle-to-cycle jitter of less than 85 ps and output-to-output skew of less than 85 ps. ICS9FG107 also provides a copy of the reference clock and 3 33 MHz PCI output clocks. Frequency selection can be accomplished via strap pins or SMBus control.

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Texas Instruments' First Integrated Circuits

1958: Invention of the Integrated Circuit
As with many inventions, two people had the idea for an integrated circuit at almost the same time. Transistors had become commonplace in everything from radios to phones to computers, and now manufacturers wanted something even better. Sure, transistors were smaller than vacuum tubes, but for some of the newest electronics, they weren't small enough.

But there was a limit on how small you could make each transistor, since after it was made it had to be connected to wires and other electronics. The transistors were already at the limit of what steady hands and tiny tweezers could handle. So, scientists wanted to make a whole circuit -- the transistors, the wires, everything else they needed -- in a single blow. If they could create a miniature circuit in just one step, all the parts could be made much smaller.

One day in late July, Jack Kilby was sitting alone at Texas Instruments. He had been hired only a couple of months earlier and so he wasn't able to take vacation time when practically everyone else did. The halls were deserted, and he had lots of time to think. It suddenly occurred to him that all parts of a circuit, not just the transistor, could be made out of silicon. At the time, nobody was making capacitors or resistors out of semiconductors. If it could be done then the entire circuit could be built out of a single crystal -- making it smaller and much easier to produce. Kilby's boss liked the idea, and told him to get to work. By September 12, Kilby had built a working model, and on February 6, Texas Instruments filed a patent. Their first "Solid Circuit" the size of a pencil point, was shown off for the first time in March.

But over in California, another man had similar ideas. In January of 1959, Robert Noyce was working at the small Fairchild Semiconductor startup company. He also realized a whole circuit could be made on a single chip. While Kilby had hammered out the details of making individual components, Noyce thought of a much better way to connect the parts. That spring, Fairchild began a push to build what they called "unitary circuits" and they also applied for a patent on the idea. Knowing that TI had already filed a patent on something similar, Fairchild wrote out a highly detailed application, hoping that it wouldn't infringe on TI 's similar device.

All that detail paid off. On April 25, 1961, the patent office awarded the first patent for an integrated circuit to Robert Noyce while Kilby's application was still being analyzed. Today, both men are acknowledged as having independently conceived of the idea.

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SECAPA AS SPECIAL EDUCATION CENTER OF THE POLICE OF REPUBLIC OF INDONESIA

To urban community and sub-province of Sukabumi have tolerated it, that from since era governance of first president of Soekarno-Hatta, town of Sukabumi this is recognized by there is its place / special school of educationor “penggodokan” all Police enlisted man cadre. Former with the title that police of output of PTIK Sukabumi Before altered to become Secapa ( era governance of belanda " Policie Shcooll").

Special it is of course to urban community citizen of sukabumi, feel proud Academic having / School education of State security government officer of R.I (state police). Popularity of town of sukabumi become " bogey" to metropoliss of diseantero Unity state of R.I this beloved. This matter of other State government officer goodness, and also and especially for all overall itself police government officer.

As real evidence from all police cadres, what have followed maximal and tight “penggodogan” and have passed better. Where they have many tired police government officer of efficacy top and success. They have acted loyal may of devotion to nation society and State of R.I (as according to doctrine of tribrata). Where police member have to ready to place forward service all kind of requirement of society specially security. Hence as according to motto and theme and also police mission and mission, is as “pengayom” of “mengayomi”, service and protector of society, according to also with applicable laws in Indonesia.

But on the otherhand all us realize also, still many all things of insuffiency, weakness both for felt by police institution and also to public society. It is of course this matter is meant by us as ordinary human being and no super human being, it is of course there is limitation of abilitys. Of insuffiency facet, weakness this is us of LSM formation of jawa west of will wishful and good submit suggestion, proposal and opinion which is positive it is of course. This such urge of summery in information ambit and direct aspiration of its source, that is urban community citizen of sukabumi this. After our party/ side of Formation LSM do/conduct monitoring and observation by “silaturahmi”, “anjang sono”, door to door and of man man to, good of society circle / citizen have level to under, middle and also especially chief of RT-RT, RW-RW, and chief of villages of se 7 district of town of sukabumi. Hence is clear is we have earned to accomodate all aspiration and informations. One of the example of of Yani society citizen have highlighted peculiarly to existence all cadres of secapa police, according to them there is no him felt and seen open in general. Especially from all police cadres of propagating / real action and become impressions felt direct by urban community citizen of sukabumi this.

From the mentioned, which/such of execution " Devote special police social from all that cadres ?", more over of is project of that by kontinue to importance of urban community citizen of sukabumi. For example devoting police social (that kader) is majored to be given decent to all orphan pass/through institution which managing in town of sukabumi. To people of jompo, continue age , lessening unemployment which there are in town of sukabumi where them still stand in need of helping. Hopefully with that way will happened a[n good relation/link between police secapa of sukabumi with urban community of sukabumi.

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