Day 2 (7-5-18) - Clock latency, source latency, network latency, insertion delay
4:18:00 PMSource Delay or Source Latency
It is known as source latency also. It is defined as "the delay from the clock origin point to the clock definition point in the design".
Delay from clock source to beginning of clock tree (i.e. clock definition point).
The time a clock signal takes to propagate from its ideal waveform origin point to the clock definition point in the design.
Network Delay (latency) or Insertion Delay
It is also known as Insertion delay or Network latency. It is defined as "the delay from the clock definition point to the clock pin of the register".
The time clock signal (rise or fall) takes to propagate from the clock definition point to a register clock pin.
The figure below shows an example of latency for a design without PLL.
latency for a design without PLL
The latency definitions for designs with PLL are slightly different.
Figure below shows latency specifications of such kind of designs.
Latency from the PLL output to the clock input of generated clock circuitry becomes source latency. From this point onwards till generated clock divides to flops is now known as network latency. Here we can observe that part of the network latency is clock to q delay of the flip flop (of divide by 2 circuit in the given example) is known value.
latency for a design with PLL
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