afs600 Actel Corporation, afs600 Datasheet - Page 244

• Manufacturer Part Number: afs600
• Description: Actel Fusion Programmable System Chips Mixed-signal Family With Optional Arm Support
• Manufacturer: Actel Corporation

Guidelines
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:
Enable Rate Definition
Output enable rate is the average percentage of time during which tristate outputs are enabled. When non-tristate
output buffers are used, the enable rate should be 100%.
Table 3-13 • Toggle Rate Guidelines Recommended for Power Calculation
Table 3-14 • Enable Rate Guidelines Recommended for Power Calculation
3 -2 0
Component
α
α
Component
β
β
β
β
Actel Fusion Programmable System Chips
1
2
3
4
1
2
• 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.
Toggle rate of VersaTile outputs
I/O buffer toggle rate
I/O output buffer enable rate
RAM enable rate for read operations
RAM enable rate for write operations
NVM enable rate for read operations
Definition
Definition
A d v a n c e d v 1 . 4
Guideline
Guideline
12.5%
12.5%
100%
10%
10%
0%