DS-FND-BSX-PC Xilinx Inc, DS-FND-BSX-PC Datasheet - Page 291

• Manufacturer Part Number: DS-FND-BSX-PC
• Description: FOUNDATION BASE SYS W/SYN EXPRES
• Manufacturer: Xilinx Inc
• Type: Foundation Systemr

Specifications of DS-FND-BSX-PC

• For Use With/related Products: Xilinx Programmable Logic Devices
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 122-1185

Foundation Series 2.1i User Guide
equals the clock period, all that you need are the three constraints
shown in the following example.
Note: When you use net name wild cards in OFFSETS, make sure
that the name is unique to valid nets; otherwise processing errors will
occur.
If you need to account for extra delay external to the FPGA, then you
could add the following.
The PERIOD constraint covers all pad-to-setup and clock-to-setup
timing paths. The OFFSET constraint covers the clock-to-pad timing
for each of the output nets beginning with OUT. Both the OFFSET
and PERIOD constraints account for the delay of the Clock Buffer/
Net in the I/O timing calculations.
The following PCF fragment illustrates the differences in syntax
between the UCF and PCF languages. In addition to the syntactical
changes, remember that net and instance names may change. As an
example, one of the net matches resulting from the UCF “NET OUT*”
constraint is now applied to “COMP OUT1_PAD”. The name
OUT1_PAD is the name assigned to the pad instance. In addition to
name changes, another difference is the verbosity of the PCF. In the
PCF there is additional syntax for “MAXDELAY,” “TIMEGRP,” and
“PRIORITY.” These are all optional qualifications of the Timespec
within the UCF, but written explicitly to the PCF file illustrating the
full flexibility of the language.
# Global UCF example
# Global PCF example
SCHEMATIC START;
. . .
NET PERIOD “CLK_IN” = 40 nS HIGH 50.00% ;
COMP “OUT1_PAD” OFFSET = OUT 40 ns AFTER COMP “CLK”;
COMP “OUT2_PAD” OFFSET = OUT 40 ns AFTER COMP
“CLK”;COMP “INPUT1_PAD” OFFSET = IN 28 ns BEFORE COMP
“CLK”;
NET CLK1 PERIOD = 40 ;
NET OUT* OFFSET = OUT 13 AFTER CLK ;
TIMESPEC TS01 = FROM PADS TO PADS 40 ;
NET INPUT* OFFSET = IN 8 BEFORE CLK ;
Foundation Constraints
B-19