Altera PowerPlay Early Power Estimator for Altera CPLDs - Manual (Page 21)

Chapter 2: PowerPlay Early Power Estimator Worksheets 2–11
Power Estimation Using the PowerPlay Early Power Estimator
December 2010 Altera Corporation PowerPlay Early Power Estimator for Altera CPLDs User Guide
Each row in the I/O module represents a design module where the I/O pins have the
same frequency, toggle percentage, average capacitive load, I/O standard, and I/O
bank.
Figure 2–11 shows the I/O module of the PowerPlay EPE spreadsheet.
Table 2–10 lists the I/O module parameters in the I/O worksheet of the PowerPlay
EPE spreadsheet.
Figure 2–11. I/O Module Setting
Table 2–10. I/O Module Section Information (Part 1 of 2)
Column Heading Description
Module Specify a name for the module in this column. This is an optional value.
I/O Standard
Select the I/O standard for the input, output, or bidirectional pins in this module from the
pull-down list. The calculated I/O power varies based on the I/O standard.
Clock Freq (MHz)
Enter the clock frequency (in MHz). This value is limited by the maximum frequency
specification for the device families.
A 100 MHz input clock with a 12.5% toggle means that each I/O pin toggles 12.5 million times
per second (100 × 12.5%).
# Output Pins Enter the number of output pins in this module.
# Input Pins Enter the number of input pins in this module.
# Bidir Pins
Enter the number of bidirectional pins in this module.
An I/O pin configured as bidirectional but is used only as an output pin consumes more power
than an I/O configured as an output-only pin due to the toggling of the input buffer every time
the output buffer toggles as they share a common pin.
I/O Bank
Select the I/O bank for the module. If you do not know which I/O bank the pins will be assigned
to, leave the value as “?”. Assigning the I/O module to a bank ensures whether your I/O voltage
assignments are compatible or not, allowing per bank I
CCIO
reporting.
The PowerPlay EPE spreadsheet does not take any I/O placement constraints into
consideration except for the I/O standard and bank match and the I/O voltage.
Toggle %
Enter the average percentage of input, output, and bidirectional pins toggling on each clock
cycle. For input pins used as clocks, the toggle percentage ranges from 0 to 200% because
clocks toggle at twice the frequency.
Typically, the toggle percentage is 12.5%. To be more conservative, you can use a higher toggle
percentage.