Answers Database
CPLD : 9500: How to utilize the Wired-AND (WAND) in the UIM
Record #2579
Product Family: Software
Product Line: CPLD Implementation
Product Part: hitop
Problem Title:
CPLD : 9500: How to utilize the Wired-AND (WAND) in the UIM
Problem Description:
Urgency: standard
General Description: How can a user utilize the Wired-AND
capibilities in the UIM of the 9500.
Note that this capability does not exist for the 9500XL/XV.
Solution 1:
XACT:
By default, the 9500 fitter software will attempt to
automatically utilize this feature if it is possible.
However, if a designer wants to force this to occur,
this can be done by attaching the following attribute
on the desired AND gate:
OPT=UIM
Note: the wired-AND feature is implemented in the UIM.
Thus, the inputs to the desired AND gate must come
from feedback loops. Thus, if any of the AND gate inputs
are from inputs pins, the UIM wired-AND can not be used
to implement the AND gate.
Also, a wired-AND function can be implemented in the UIM only
for a single level of logic.
For example, if your equation looks like y = a*b*c, it can be
implemented as a wired-AND. However, if your function looks
like z = c*d + e*f, then you can implement the function z as
one wired-AND gate. You will need two AND gates to implement
that.
Solution 2:
1.X/2.1i
The same details are true for M1 except for the syntax placed
on the logic on the schematic.
WIREAND
is the attribute added to an AND gate to force HITOP to place
the gate in the UIM.
To place this attribute in a UCF file:
NET signal_name WIREAND;
where signal_name is the output signal of the AND gate.
End of Record #2579 - Last Modified: 12/17/99 13:43 |
