Answers Database
How to specify a BUFGP vs. BUFGS using Viewsynthesis?
Record #973
Product Family: Software
Product Line: ViewLogic
Product Part: Viewsynthesis
Product Version: 5.0.2x
Problem Title:
How to specify a BUFGP vs. BUFGS using Viewsynthesis?
Problem Description:
Viewsynthesis by default infers a BUFG on the clock inputs and doesn't let you
specify whether it is going to be a BUFGP or a BUFGS.
This solution applies to Viewsynthesis 5.02x and Workview Office 7.3 and newer.
Solution 1:
Here is a way to work-around this problem:
1) copy xc4000.fpn into the local directory
2) delete (or comment out) the line:
clocksyms bufg bufg bufg bufg
3) create a Pad Symbol for bufgp and bufgs by adding the following
lines to the "Pad symbols" section of the xc4000.fpn file:
symbol clkbuf bufgp
pins in i
pins out o
symbol clkbuf bufgs
pins in i
pins out o
4) create a design.fpn file in the project directory with the following instructions:
clocksyms bufgp bufgp bufgs bufgs
| a comment
clock 1 rst
clock 2 clk
clock 3 inn[0]
clock 4 inn[1]
Note that the line:
clocksyms bufgp bufgp bufgs bufgs
causes the two first clocks to be driven by a BUFGP and the two following
ones by a BUFGP.
Note that the line:
clock 1 rst
causes Viewsyn to treat the input signal "RST" as a clock (with the
highest priority). It will then use a BUFGP for it.
End of Record #973 - Last Modified: 08/05/97 13:53 | 
