Timing: Difference between revisions
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= | [[Dynamic discipline]] helps. Slowing the clock usually works. Sequencing overhead is tpcq + tsetup | ||
= Output timing = | |||
The amount of time passed before the output follows the input is the [[propagation delay]]. It is the maximum delay from input to output. During this time, the output is unpredictable. | The amount of time passed before the output follows the input is the [[propagation delay]]. It is the maximum delay from input to output. During this time, the output is unpredictable. | ||
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We generally do not measure the delays of an individual component, which involves calculating the timing of the [[critical path]]. They are usually given. | We generally do not measure the delays of an individual component, which involves calculating the timing of the [[critical path]]. They are usually given. | ||
The [[setup time]] is the minimum time between input stabilization and clock switching. The [[hold time]] is after. | = Input timing = | ||
The [[setup time]] is the minimum time between input stabilization and clock switching. The [[hold time]] is after. These two constitute the [[aperture time]] around the clock edge. The [[dynamic discipline]] states that input must be stable during [[aperture time]] | |||
= Flip Flop = | |||
Propagation delay and contamination delay of clock to Q is is denoted differently for flip-flops. <math>t_{ccq}</math> and <math>t_{pcq}</math> | |||
[[Category:Computer Architecture]] | [[Category:Computer Architecture]] | ||
Latest revision as of 21:56, 4 June 2024
Dynamic discipline helps. Slowing the clock usually works. Sequencing overhead is tpcq + tsetup
Output timing
The amount of time passed before the output follows the input is the propagation delay. It is the maximum delay from input to output. During this time, the output is unpredictable.
Since the output is unpredictable during the time after input and before propagation delay passed, it is possible to read an output during this time. This is the contamination delay: the minimum delay from input to output.
The reason for the unpredictability at contamination delay is due to physics.
We generally do not measure the delays of an individual component, which involves calculating the timing of the critical path. They are usually given.
Input timing
The setup time is the minimum time between input stabilization and clock switching. The hold time is after. These two constitute the aperture time around the clock edge. The dynamic discipline states that input must be stable during aperture time
Flip Flop
Propagation delay and contamination delay of clock to Q is is denoted differently for flip-flops. and
