Logic Racing Problems Or Measurements

[stanleystan]

When does a tech. test for Logic Racing?

What causes Logic Racing Problems?

 

[D.A.(Tony)Stewart]

When does a tech. test for Logic Racing?

What causes Logic Racing Problems?

Bad design and component variation with supplier and temperature.

When a flipflop or register has an edge sensitive clock with data changing just before that, it is a race to see which edge arrives first.

If however a series of flipflops are cascaded but all clocked by the same edge, then the data is forced to be change after the clock. If the clock is too fast for data to settle, then another race condition can happen, in which case, one can decide to force the race to win by several methods such as; using an opposite phase , or a staggered or a slower clock.

 

[stanleystan]

So a Logic Race is a time difference/duration between a Clock signal compared to data or what logic signals?

 

[D.A.(Tony)Stewart]

Yes it is always between 2 or more signals.

If two signals in an OR gate which are opposite and change at the same time, you can expect a glitch from this race between two simultaneous changing inputs each which drive the output.

 

[stanleystan]

But when would you want to measure a logic Race or how do you know there is a Logic Race problem?

 

[D.A.(Tony)Stewart]

when u get truthful answers in logic, unlikely there is a race.

If you seem to be getting illogical responses or a glitch, then you can suspect this unstable condition and research the design. Others are suspecting other forms of unstable conditions in these questions.