X Transition Power Analysis in PrimePower

• Average power analysis

  • Not consider the duration of the X when calculating toggle rates and static probabilities
  • X are not used in propagation to determine the switching activity of nets not present in the activity file
  • For nets in the X for the entire simulation, PrimePower assumes half high and half low, and toggle at lease once
    • May lead to unwanted switching activity during propagation, increase in power consumption
  • Toggle rate = [0.5 * (number of 0/1 to X transition) + 0.5 * (number of X to 1/0 transition)) / Total Duration
    • 0->x->1 : 1 toggle
    • 1->x->0 : 1 toggle
  • Glitch Toggle Rate : A transition from a known logic value to an X and back to a different known logic value
  • Static Probability = Time at Logic 1 / (Total simulation time – Time in X state)
  • SAIF Syntax
    • DURATION : Total Simulation Time
    • TIMESCALE Time units
    • T0: Duration at logic 0
    • T1: Duration at logic 1
    • TX: Duration at logic X
    • TC : Number of toggles between: known logic states
    • IG: Number of inertial glitch
  • VCD
    • Total Simulation Time = (Simulation end time – Start time)
      • If there is a value change on the net
        SP = Time at 1/(Total Simulation Time – time at X)
        TR = [0.5*(number of 0/1 to X transition)+0.5 *(number of X to 1/0 transition)}/ (Total Duration)
      • If the net remains in the X state:
        SP = 0.5
        TR = 0