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    race around condition in digital electronics

    hi all

    define RACE CONDITION in digital electronics?? On what basis it occurs? How to rectify it??

    thnx in advance for your favourable reply

    •   Alt20th March 2008, 10:20

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    race around condition in flip flops

    In JK flip flop whne the value of J and K =1 and at the same time vlaue of clock is 1 ,so according to the truth table of J=k=1 the value of output should be toggled so the value keep on changing till the change in the clock pulse.which is not acceptable .This problem can be removed by making it master slave.or making ff as edge triggered.


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    •   Alt20th March 2008, 11:02

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    Re: race around condition in flip flops

    Quote Originally Posted by gurpreet.singh View Post
    In JK flip flop whne the value of J and K =1 and at the same time vlaue of clock is 1 ,so according to the truth table of J=k=1 the value of output should be toggled so the value keep on changing till the change in the clock pulse.which is not acceptable .This problem can be removed by making it master slave.or making ff as edge triggered.
    consider 2 flops A ,B The clock is assumed to be reaching the both flops at the same time ideally.But practically it does not happen.There is a delay in the arrival of the clocks for A and B .Suppose the flop A is holding some data when the clock for A arrives the data in it goes out and the new data comes in.When the clock for B is delayed then the data from A has no where to go and the new data comes in to A .Because of this the data is corrupted .this is called race around condition.To eliminate this we have master and slave.


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    •   Alt30th November 2011, 17:51

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    Re: race around condition in flip flops

    The undefined condition in the SR-Flipflop is called as raceover condition it can be over come by using JK-Flipflop



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    Re: race around condition in flip flops

    Hi Bala,

    Race Around Condition is when the output keeps toggling again and again in one clock pulse and becomes indeterminate. There are three ways to rectify it:

    1. By making clock pulse less than propagation delay.
    2. By using Master Slave Flip Flop
    3. By using Edge Triggering.

    You may want to look at below link for further clarification:

    J-K Flip Flop In Digital Electronics | Vertical Horizons


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    Re: race around condition in digital electronics

    Race Condition and Race around condition are different.

    Race Condition only means that the input signals are in race to change the output. This may be due to the difference in propogation or routing delays in the signal paths. This results in glitches, but the circuit will be stable.

    Race around condition is different and is very undesirable. It usually occurs when the output triggers a change in output. This occurs in systems where output is fedback. A change in output may change the output again and again before it settles..... making the output indeterminate. This is Race Around condition. It makes the circuit unstable. This racing around (output is in race to change output) condition is called Race Around condition.



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