Answers Database
2.1i : 9500 : Hprep6 : Inverted global tristates do not tristate properly
Record #8245
Product Family: Software
Product Line: CPLD Implementation
Product Part: hprep6
Product Version: 2.1is3
Problem Title:
2.1i : 9500 : Hprep6 : Inverted global tristates do not tristate properly
Problem Description:
Urgency: Standard
General Description:
I am using an inverted global tristate in my design, and although
the simulation is fine, it does not work in the hardware. The
tristate signal is never released, even though the control signal
states it should be.
Solution 1:
A problem has been found in the CPLD fitter and how it handles
inverted tristate controls. The conditions that cause this to occur
are:
- Must be using 9536/9572/95108
(XL not affected, the other 9500 devices not affected)
and
- Must use the positive AND negative form of the global tristate
for the entire design. If the global tristates are ALL in the
positive form OR all in the negative form, there is no problem.
The workaround is to UNCHECK under the Design Manager
Options:
Use Global Output Enable(s)
This will be fixed in service pack 5.
End of Record #8245 - Last Modified: 12/15/99 11:57 |
