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

Chapter 2: Switches, Buttons, and Rotary Knob
Rotating RIGHT
A
B
Figure 2-10: Outputs from Rotary Shaft Encoder Might Include Mechanical Chatter

UCF Location Constraints

Figure 2-11
including the I/O pin assignment and the I/O standard used, and defines a pull-up or
pull-down resistor for each FPGA input.

Discrete LEDs

Locations and Labels

The Spartan-3A/3AN Starter Kit board has eight individual surface-mount LEDs located
immediately above the slide switches as shown in
through LED0. LED7 is the left-most LED, LED0 the right-most LED.
30
Rising edge on 'A' when 'B' is Low indicates RIGHT (clockwise) rotation
provides the UCF constraints for the rotary encoder/push-button switch,
NET "ROT_A" LOC
NET "ROT_B" LOC
NET "ROT_CENTER" LOC
Figure 2-11: UCF Constraints for Rotary Push-Button Switch
Figure 2-12: Eight Discrete LEDs
www.xilinx.com
Switch closing chatter on 'B'
injects false "clicks" to the LEFT
('B' rising edge when 'A' is Low)
= "T13" | IOSTANDARD
= "R14" | IOSTANDARD
= "R13" | IOSTANDARD
Figure
Spartan-3A/3AN Starter Kit Board User Guide
Switch opening chatter on 'A'
injects false "clicks" to the RIGHT
UG230_c2_07_030606
= LVTTL | PULLUP ;
= LVTTL | PULLUP ;
= LVTTL | PULLDOWN ;
2-12. The LEDs are labeled LED7
UG334_c2_12_052407
UG334 (v1.0) May 28, 2007
R