DO-CPLD-DK-G Xilinx Inc, DO-CPLD-DK-G Datasheet - Page 105

• Manufacturer Part Number: DO-CPLD-DK-G
• Description: KIT DESIGN CPLD W/BATT HOLDER
• Manufacturer: Xilinx Inc
• Series: CoolRunner™- IIr
• Type: CPLDr

Specifications of DO-CPLD-DK-G

• Contents: Proto Board, Download Cable, Samples, Software
• For Use With/related Products: CoolRunner-ll, XC9500XL
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 122-1512

Programmable Logic Design
June 12, 2006
R
17. Click OK.
18. Save the Constraints Editor session (File
CoolRunner-II architecture supports the use of non 50:50 duty cycle clocks by
implementing input hysteresis. This can be selected on a pin-by-pin basis. For example, if
the clock used in this design is an RC oscillator, the input hysteresis can be used to clean up
the clock using the following constraint syntax:
The CoolRunner-II CPLD also supports different I/O standards. If the three light signals
had to go to a downstream device that required the signals to conform to a certain I/O
standard, you could use the following constraint syntax:
The permissible standards are LVTTL, LVCMOS15, LVCMOS18, LVCMOS25, LVCMOS33.
On larger devices (128 macrocell and larger), the permissible standards are HSTL_I,
SSTL2_I, and SSTL3_I. However, you can use only one I/O standard per bank, so take care
when assigning different I/O standards in a design.
The CoolRunner-II family has several features that are aimed at reducing power
consumption in the device. One of these features is known as CoolClock. The clock signal
on Global Clock Input 2 (GCK2) is divided by 2 as soon as it enters the device. All of the
registers clocked by this clock are then automatically configured as dual-edge triggered
flip-flops. The highest toggling net in the design will now be toggling at half the frequency,
which will reduce the power consumption of that net without compromising the
performance of the design. The CoolClock attribute can be applied by right-clicking on
GCK2 in PACE or by adding the following line in the UCF:
Notice that the Clock to Pad fields have been filled in automatically and that the UCF
generated has appeared in the UCF constraints tab at the bottom of the screen.
The UCF file should look similar to
Editor.
NET “clock” schmitt_trigger;
NET “red_light” IOSTANDARD=LVTTL;
NET “clock” COOL_CLK;
Figure 5-12: Complete Constraints List
www.xilinx.com
Figure
5-12.
→
Save) and exit the Constraints
Constraints Editor
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