Altera Early SSN Estimator - Manual (Page 6)

1–2 Chapter 1: Early SSN Estimator
Setting up the Early SSN Estimator
Early SSN Estimator User Guide for Altera Programmable Devices © November 2009 Altera Corporation
■ Release Notes —contains information about the current version of the tool. It also
lists the changes from the previous versions of the tool.
■ Signal Integrity Center —provides a link to information dedicated exclusively to
signal integrity on Altera’s website ( www.altera.com ).
■ Reset —used to clear all the data that is entered into the Calculator tab.
In the Calculator tab, there are two kinds of parameters:
■ Global parameters
■ Parameters Specific to I/O Bank
Global Parameters
Figure 1–2 shows the global parameters (desired margin and result mode) listed
under the Options section in the Calculator tab. The ESE calculates the far-end noise,
assuming a worst-case placement of pins. Worst-case pin placement assumes that
aggressor pins are packed as closely as possible to the worst-case victim pin.
Desired Margin
The desired margin sets the amount of margin that you want to allocate for non-SSN
related items. This margin is applicable to all banks that are populated in the
Calculator
tab. By default, the ESE assumes that the entire noise margin is allocated to
SSN. You can enter this value in either volts or percentage of noise margin, depending
on the setting you chose in the Result Mode parameter.
Result Mode
The ESE can report results in two different formats: volts and percentage margin. The
default format is to report both noise and margin in volts. In percentage margin mode,
noise is reported as volts but the margin is expressed as a percentage of the total
zero-noise margin. When the victim net is driven low, the noise margin is calculated
using
Equation 1–1 . When driven high, Equation 1–2 is used.
Figure 1–1. Tabs in the ESE Tool
Figure 1–2. Defining Global Parameters