Ucf Location Constraints; Discrete Leds; Locations And Labels - Xilinx Spartan-3E User Manual

R
direction! See the Rotary Encoder Interface reference design
example.
Rotating RIGHT
A
B
Figure 2-8: Outputs from Rotary Shaft Encoder May Include Mechanical Chatter

UCF Location Constraints

Figure 2-9
I/O pin assignment and the I/O standard used, and defines a pull-down resistor on each
input.

Discrete LEDs

Locations and Labels

The Spartan-3E Starter Kit board has eight individual surface-mount LEDs located above
the slide switches as shown in
LED7 is the left-most LED, LED0 the right-most LED.
Spartan-3E Starter Kit Board User Guide
UG230 (v1.0) March 9, 2006
Rising edge on 'A' when 'B' is Low indicates RIGHT (clockwise) rotation
provides the UCF constraints for the four push-button switches, including the
NET "ROT_A" LOC
NET "ROT_B" LOC
NET "ROT_CENTER" LOC
Figure 2-9: UCF Constraints for Rotary Push-Button Switch
Figure 2-10: Eight Discrete LEDs
www.xilinx.com
Switch closing chatter on 'B'
injects false "clicks" to the LEFT
('B' rising edge when 'A' is Low)
= "K18" | IOSTANDARD = LVTTL |
= "G18" | IOSTANDARD = LVTTL |
= "V16" | IOSTANDARD = LVTTL |
Figure 2-10. The LEDs are labeled LED7 through LED0.
UG230_c2_04_021206
Discrete LEDs
in"Related Resources" for an
Switch opening chatter on 'A'
injects false "clicks" to the RIGHT
UG230_c2_07_030606
PULLUP ;
PULLUP ;
PULLDOWN ;
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