2.2.4.2.1 Toggle Rate Definition

A toggle rate defines the frequency of a net or logic element relative to a clock. It is a percentage. If the toggle rate of a net is 100%, this means that the net switches at half the clock frequency. Below are some examples:

• The average toggle rate of a shift register is 100%, as all flip-flop outputs toggle at half of the clock frequency.
• The average toggle rate of an 8-bit counter is 25%:
  • Bit 0 (LSB) = 100%
  • Bit 1 = 50%
  • Bit 2 = 25%
  • …
  • Bit 7 (MSB) = 0.78125%
  • Average toggle rate = (100% + 50% + 25% + 12.5% + . . . 0.78125%) / 8.