How Can a D-Type Flip Flop Handle Simultaneous High Inputs?

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A D-type flip flop can encounter issues when both SET and RESET inputs are high, leading to ambiguous outputs. In this scenario, the RS NAND latch can produce two possible states: Q = 0 with Q(not) = 1 or Q = 1 with Q(not) = 0. The actual output depends on the previous states of the inputs, creating uncertainty in the output behavior. This ambiguity arises from the conflicting inputs to the NAND gates, where one input is known and the other is influenced by the output of another gate. Understanding the timing and previous input states is crucial for resolving these simultaneous high input conditions.
transgalactic
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http://img329.imageshack.us/my.php?image=39501432oa1.jpg

if one of them was 0 then no problem because the other wire value doesn't matter
but here we have both 1
if i look on one of the NANDs gates we have one input of 1
and the other input value is unknown because it comes from the resolt of the other gate
which has the same problem

how to solve it??
 
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When SET = RESET = 1, there are two likely outputs of our RS NAND latch. We can have Q = 0 and Q(not) = 1. In this case, the input to the lower NAND gate is 0 and 1, which gives Q(not) = 1. The inputs to the first NAND are both 1 which makes Q = 0.

The second possibility is to have Q = 1 and Q(not) = 0. The same analysis used above can be applied for this situation.

So which situation occurs first? This depends on what has occurred previously at the inputs.
 
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